1. A preparation method of umbilical cord mesenchymal stem cell supernatant is characterized by comprising the following steps: the preparation method comprises the following steps:

(1) collecting umbilical cord mesenchymal stem cell culture solution, adding citric acid fatty glyceride, and mixing uniformly, wherein the content of the citric acid fatty glyceride is 0.01-0.1%;

(2) adding parthenolide into the mixture obtained in the step (1), wherein the concentration of the parthenolide is 50-200 mu g/mL, and uniformly mixing;

(3) centrifuging the mixture of the step (2) and taking the supernatant.

2. The method of claim 1, wherein:

the content of the citric acid fatty glyceride in the step (1) is 0.01-0.05%;

the concentration of the parthenolide in the step (2) is 80-150 mu g/mL.

3. A culture medium of primary umbilical cord mesenchymal stem cells is characterized in that: the culture medium comprises umbilical cord mesenchymal stem cell supernatant prepared by the preparation method of any one of claims 1-2.

4. The culture medium of claim 3, wherein: the culture medium also comprises a mesenchymal stem cell serum-free culture medium and parthenolide.

5. The culture medium according to claim 4, wherein: the volume ratio of the umbilical cord mesenchymal stem cell supernatant to the mesenchymal stem cell serum-free culture medium is 1: 0.5-2.

6. The culture medium of claim 5, wherein: the volume ratio of the umbilical cord mesenchymal stem cell supernatant to the mesenchymal stem cell serum-free culture medium is 1: 1.

7. The culture medium of claim 6, wherein: the final concentration of the parthenolide is 5-15 mu mol/L.

8. The culture medium of claim 7, wherein: the final concentration of the parthenolide is 10 mu mol/L.

9. Use of umbilical cord mesenchymal stem cell supernatant prepared by the preparation method of any one of claims 1 to 2 or the culture medium of any one of claims 3 to 8 in the preparation of primary umbilical cord mesenchymal stem cells.

10. A preparation method of primary umbilical cord mesenchymal stem cells is characterized by comprising the following steps: the preparation method comprises the following steps:

(1) and (3) detection: detecting exogenous factors of the peripheral blood of the puerpera, wherein the exogenous factors comprise treponema pallidum, AIDS virus, hepatitis B virus, hepatitis C virus, human cytomegalovirus, human herpesvirus and T lymphocyte leukemia virus, and ensuring that the umbilical cord does not contain the exogenous factors;

(2) treating umbilical cord to obtain tissue block of Wharton's jelly, spreading in culture dish, adding serum-free culture medium of mesenchymal stem cells, and placing in CO₂Culturing in a culture box, and changing liquid every two days, wherein the liquid changing culture medium is the culture medium of the primary umbilical cord mesenchymal stem cells, and carrying out passage when the cell fusion degree reaches 50%;

(3) cell passage: washing cells with normal saline for 2 times, adding pancreatin for digestion, centrifuging, inoculating, and culturing for passage.

Background

Mesenchymal Stem Cells (MSCs) are a type of pluripotent stem cells derived from early-developing mesoderm, have the potential of self-renewal and multi-differentiation, have the characteristics of low immunogenicity, strong proliferation capacity and the like, and are widely present in tissues such as bone marrow, fat, umbilical cord, placenta, teeth, synovium and the like. The Umbilical Cord Mesenchymal Stem Cells (UCMSCs) are multipotent Stem Cells existing in Umbilical cord tissues of newborn, and compared with Mesenchymal Stem Cells from other tissues, the Umbilical cord Mesenchymal Stem Cells have the advantages of rich sources, convenient material taking, no ethical dispute, low immunogenicity and the like.

The umbilical cord mesenchymal stem cells have the ability to differentiate into adipocytes, chondrocytes and osteocytes under specific induction conditions in vivo or in vitro. Because of the potential of multidirectional differentiation, the medicine can be widely applied to the treatment of diseases such as nervous system diseases, cardiovascular system diseases, blood system diseases, immune system diseases, diabetes, muscle degeneration diseases, liver diseases, chronic pain and the like in clinic, and has very wide application prospect. The umbilical cord mesenchymal stem cells can also secrete exosomes, and the exosomes contain various molecular components including proteins, lipids, Messenger ribonucleic acid (mRNA) and micro ribonucleic acids (miRNAs) and have the functions of performing immune regulation, promoting cell regeneration, promoting angiogenesis and the like.

The industrialization development of stem cells comprises an upstream stem cell bank, a midstream stem cell amplification technology and a quality inspection technology, and a downstream stem cell product. Many organizations at home and abroad are developing the storage work of mesenchymal stem cells, and a method for separating the stem cells from the umbilical cord in a short time and high efficiency becomes extremely important. At present, the most widely applied method for preparing the primary mesenchymal stem cells at home and abroad is a tissue block adherence method. The development of the traditional tissue block adherence method can not keep pace with stem cell research, the tissue block adherence method has long culture time and low separation efficiency, and the long-time culture increases the probability of various bacteria pollution. Therefore, it becomes important to improve the conventional tissue mass adherence method and shorten the primary culture time to meet the requirements of clinical and scientific research.

In the primary stem cell preparation method, some patents improve the traditional tissue block adherence method by optimizing the culture medium, such as patents CN201480030461.1, CN201910155437.5, CN201910334392.8, etc., and by formulating the own culture medium for use in the primary preparation and passage process, although the isolation culture period is also improved, the own culture medium is not stabilized by the commercial culture medium. There are also patents and literature for recycling tissue pieces for reattachment during primary culture, such as patent CN201711365354.6 and "research on primary culture of myogenic stem cells of large adult mammals sheep by modified differential adherent method" (lefen et al, family planning and obstetrics in china, 2017, vol 9, No. 12, p 25-29).

Therefore, it is highly desirable to provide a culture medium and a culture method that significantly shortens the primary culture time of umbilical cord mesenchymal stem cells and has a high cell viability rate.

Disclosure of Invention

In order to solve the above problems in the prior art, the present application provides a culture medium of primary umbilical cord mesenchymal stem cells and applications thereof. Compared with the traditional tissue block wall pasting method, the culture medium provided by the invention has the advantages that the culture time is obviously shortened, and no obvious difference exists in phenotype, cell viability, osteogenesis induction capacity and proliferation growth curve.

In order to achieve the above object, the present invention provides the following technical solutions:

in one aspect, the invention provides a preparation method of umbilical cord mesenchymal stem cell supernatant, which comprises the following steps:

(1) collecting umbilical cord mesenchymal stem cell culture solution, adding citric acid fatty glyceride, and mixing uniformly, wherein the content of the citric acid fatty glyceride is 0.01-0.1%;

(2) adding parthenolide into the mixture obtained in the step (1), wherein the concentration of the parthenolide is 50-200 mu g/mL, and uniformly mixing;

(3) centrifuging the mixture of the step (2) and taking the supernatant.

Specifically, the content of the citric acid fatty acid glyceride in the step (1) is 0.01-0.05%, and preferably 0.03%.

Specifically, the concentration of parthenolide in step (2) is 80-150. mu.g/mL, preferably 100. mu.g/mL.

In another aspect, the invention provides a culture medium of primary umbilical cord mesenchymal stem cells, wherein the culture medium comprises the umbilical cord mesenchymal stem cell supernatant.

Specifically, the culture medium further comprises a mesenchymal stem cell serum-free culture medium and parthenolide.

More specifically, the volume ratio of the umbilical cord mesenchymal stem cell supernatant to the mesenchymal stem cell serum-free culture medium is 1:0.5-2, preferably 1: 1.

More specifically, the final concentration of the parthenolide is 5-15 mu mol/L, and preferably 10 mu mol/L.

In another aspect, the invention provides an application of the umbilical cord mesenchymal stem cell supernatant or the culture medium of the primary umbilical cord mesenchymal stem cell in preparation of the primary umbilical cord mesenchymal stem cell.

In another aspect, the present invention provides a method for preparing primary umbilical cord mesenchymal stem cells, comprising the steps of:

(1) and (3) detection: detecting exogenous factors of the peripheral blood of the puerpera, wherein the exogenous factors comprise treponema pallidum, AIDS virus, hepatitis B virus, hepatitis C virus, human cytomegalovirus, human herpesvirus and T lymphocyte leukemia virus, and ensuring that the umbilical cord does not contain the exogenous factors;

(2) treating umbilical cord to obtain tissue block of Wharton's jelly, spreading in culture dish, adding serum-free culture medium of mesenchymal stem cells, and placing at 37 deg.C in CO₂CO concentration of 5%₂Culturing in a culture box, and changing liquid every two days, wherein the liquid changing culture medium is the culture medium of the primary umbilical cord mesenchymal stem cells, and carrying out passage when the cell fusion degree reaches 50%;

(3) cell passage: washing cells with normal saline for 2 times, adding pancreatin for digestion, centrifuging, inoculating, and culturing for passage.

Specifically, the pancreatin in the step (3) is 0.025-0.05% of trypsin.

Compared with the prior art, the invention has the following beneficial effects:

during the stem cell culture process, the supernatant contains a plurality of cytokines and exosomes secreted by the stem cells, and the factors and the exosomes can promote the climbing and rapid proliferation of the stem cells from the tissue blocks through research. According to the invention, the umbilical cord mesenchymal stem cell supernatant and/or parthenolide are/is adopted to culture the primary cells, so that the preparation time of the primary umbilical cord mesenchymal stem cells can be effectively shortened, and the better cell viability, phenotype and function of the primary umbilical cord mesenchymal stem cells are maintained.

Drawings

FIG. 1 is a graph of the viability and phenotype of primary human umbilical cord mesenchymal stem cells according to the method described in example 1.

Fig. 2 is a graph of the viability and phenotype of primary human umbilical cord mesenchymal stem cells according to the method described in example 2.

FIG. 3 is a graph of the viability and phenotype of primary human umbilical cord mesenchymal stem cells according to the method described in example 3.

FIG. 4 is a graph of the viability and phenotype of primary human umbilical cord mesenchymal stem cells according to the method described in example 4.

Fig. 5 is a graph of the viability and phenotype of primary human umbilical cord mesenchymal stem cells according to the method described in example 5.

FIG. 6 is a graph of the viability and phenotype of primary human umbilical cord mesenchymal stem cells according to the method described in example 6.

FIG. 7 is a graph of the viability and phenotype of primary human umbilical cord mesenchymal stem cells according to the method described in comparative example 1.

FIG. 8 is the experiment of differentiation induced by adipogenesis of human umbilical cord mesenchymal stem cells cultured by different embodiments.

FIG. 9 is the osteogenic differentiation experiment of human umbilical cord mesenchymal stem cells cultured by different embodiments.

FIG. 10 is a graph of the growth of human umbilical cord mesenchymal stem cells cultured by the methods of the different embodiments.

Detailed Description

The present invention will be further illustrated in detail with reference to the following specific examples, which are not intended to limit the present invention but are merely illustrative thereof. The experimental methods used in the following examples are not specifically described, and the materials, reagents and the like used in the following examples are generally commercially available under the usual conditions without specific descriptions.

The examples, where no specific techniques or conditions are indicated, are carried out according to the techniques or conditions described in the literature of the art (for example, see J. SammBruk et al, molecular cloning, A laboratory Manual, third edition, scientific Press, ed. by Huang Pe, et al) or according to the instructions of the product.

Example 1 umbilical cord mesenchymal stem cell supernatant and Primary umbilical cord mesenchymal stem cell Medium thereof

1. Preparing umbilical cord mesenchymal stem cell supernatant:

(1) collecting umbilical cord mesenchymal stem cell culture solution, adding citric acid fatty glyceride, and mixing uniformly, wherein the content of the citric acid fatty glyceride is 0.03%;

(2) adding parthenolide into the mixture obtained in the step (1), wherein the concentration of parthenolide is 100 mug/mL, uniformly mixing, and keeping the temperature at 37 ℃ for 10 min;

(3) and (3) centrifuging the mixture obtained in the step (2) for 10min at 4 ℃ under the condition of 12000r/min, and taking a supernatant.

2. Primary umbilical cord mesenchymal stem cell culture medium

The method comprises the steps of 1, preparing umbilical cord mesenchymal stem cell supernatant, mesenchymal stem cell serum-free culture medium (Gibco company, product number C12571500BT or AventaCell company, product number HPCFDCRL50) and parthenolide (Sigma-Aldrich company), wherein the volume ratio of the umbilical cord mesenchymal stem cell supernatant to the mesenchymal stem cell serum-free culture medium is 1:1, and the final concentration of the parthenolide is 10 mu mol/L.

Example 2 umbilical cord mesenchymal stem cell supernatant and Primary umbilical cord mesenchymal stem cell culture Medium thereof

1. Preparing umbilical cord mesenchymal stem cell supernatant:

collecting umbilical cord mesenchymal stem cell culture solution, centrifuging for 10min at 4 deg.C and 12000r/min, and collecting supernatant.

2. Primary umbilical cord mesenchymal stem cell culture medium

The method comprises the steps of 1, preparing the umbilical cord mesenchymal stem cell supernatant, a mesenchymal stem cell serum-free culture medium and parthenolide, wherein the volume ratio of the umbilical cord mesenchymal stem cell supernatant to the mesenchymal stem cell serum-free culture medium is 1:1, and the final concentration of the parthenolide is 10 mu mol/L.

Example 3 umbilical cord mesenchymal stem cell supernatant and Primary umbilical cord mesenchymal stem cell culture Medium thereof

1. Preparing umbilical cord mesenchymal stem cell supernatant:

(1) collecting umbilical cord mesenchymal stem cell culture solution, adding citric acid fatty glyceride, and mixing uniformly, wherein the content of the citric acid fatty glyceride is 0.03%;

(2) adding parthenolide into the mixture obtained in the step (1), wherein the concentration of parthenolide is 100 mug/mL, uniformly mixing, and keeping the temperature at 37 ℃ for 10 min;

(3) and (3) centrifuging the mixture obtained in the step (2) for 10min at 4 ℃ under the condition of 12000r/min, and taking a supernatant.

2. Primary umbilical cord mesenchymal stem cell culture medium

The method comprises the steps of 1, preparing umbilical cord mesenchymal stem cell supernatant and a mesenchymal stem cell serum-free culture medium, wherein the volume ratio of the umbilical cord mesenchymal stem cell supernatant to the mesenchymal stem cell serum-free culture medium is 1: 1.

Example 4 Primary umbilical cord mesenchymal Stem cell culture Medium

Comprises a mesenchymal stem cell serum-free culture medium and parthenolide, wherein the final concentration of parthenolide is 10 mu mol/L.

Example 5 umbilical cord mesenchymal stem cell supernatant and Primary umbilical cord mesenchymal stem cell culture Medium thereof

1. Preparing umbilical cord mesenchymal stem cell supernatant:

(1) collecting umbilical cord mesenchymal stem cell culture solution, adding citric acid fatty glyceride, and mixing uniformly, wherein the content of the citric acid fatty glyceride is 0.03%;

(2) adding parthenolide into the mixture obtained in the step (1), wherein the concentration of parthenolide is 100 mug/mL, uniformly mixing, and keeping the temperature at 37 ℃ for 10 min;

(3) and (3) centrifuging the mixture obtained in the step (2) for 10min at 4 ℃ under the condition of 12000r/min, and taking a supernatant.

2. Primary umbilical cord mesenchymal stem cell culture medium

The method comprises the steps of 1, preparing the umbilical cord mesenchymal stem cell supernatant, a mesenchymal stem cell serum-free culture medium and parthenolide, wherein the volume ratio of the umbilical cord mesenchymal stem cell supernatant to the mesenchymal stem cell serum-free culture medium is 1:0.5, and the final concentration of the parthenolide is 5 mu mol/L.

Example 6 umbilical cord mesenchymal stem cell supernatant and Primary umbilical cord mesenchymal stem cell culture Medium thereof

1. Preparing umbilical cord mesenchymal stem cell supernatant:

(1) collecting umbilical cord mesenchymal stem cell culture solution, adding citric acid fatty glyceride, and mixing uniformly, wherein the content of the citric acid fatty glyceride is 0.03%;

(2) adding parthenolide into the mixture obtained in the step (1), wherein the concentration of parthenolide is 100 mug/mL, uniformly mixing, and keeping the temperature at 37 ℃ for 10 min;

(3) and (3) centrifuging the mixture obtained in the step (2) for 10min at 4 ℃ under the condition of 12000r/min, and taking a supernatant.

2. Primary umbilical cord mesenchymal stem cell culture medium

The method comprises the steps of 1, preparing the umbilical cord mesenchymal stem cell supernatant, a mesenchymal stem cell serum-free culture medium and parthenolide, wherein the volume ratio of the umbilical cord mesenchymal stem cell supernatant to the mesenchymal stem cell serum-free culture medium is 1:2, and the final concentration of the parthenolide is 15 mu mol/L.

Example 7 preparation of Primary umbilical cord mesenchymal Stem cells

(1) And (3) detection: exogenous factor detection is carried out on the maternal peripheral blood quality inspection part, and enzyme linked immunosorbent assay (ELISA) diagnostic kits are adopted to detect exogenous factors such as treponema pallidum, AIDS virus, hepatitis B virus, hepatitis C virus, human cytomegalovirus, human herpesvirus (EBv), T-lymphoblastic leukemia virus and the like, so as to ensure that the umbilical cord does not contain the exogenous factors.

(2) Washing two bundled umbilical cords twice with sterile PBS buffer solution, soaking and sterilizing with 75% alcohol for 1min, cutting the umbilical cords into 2cm segments with surgical scissors, and cleaning residual serum with sterile PBS buffer solution. Removing one vein from two arteries inside the umbilical cord, removing Wharton's jelly on the inner surface of the umbilical cord, and washing with PBS buffer solution for 3 times.

Shearing Buton rubber into 1mm³Then spread in a 150mm cell culture dish, taking note of the gap between the tissue blocks, and the dish was placed at 37 ℃ in 5% CO₂CO concentration₂Standing in the incubator for 20min, slowly dropwise adding 30mL of mesenchymal stem cell serum-free culture medium into the culture dish, and performing CO treatment at 37 deg.C₂CO concentration of 5%₂Culturing in an incubator. Every two daysThe solution was changed again. Wherein, the primary umbilical cord mesenchymal stem cell culture medium during liquid change is prepared according to the steps of the embodiment 1 to 6 respectively.

(3) Cell passage: the time to 50% cell confluence was recorded (Table 1), and passaging was performed until 50% cell confluence was reached, respectively. Discarding the supernatant, washing the cell surface with 0.9% normal saline for 2 times, adding 3mL of 0.05% pancreatin into each dish for digestion, adding 6mL of mesenchymal stem cell serum-free culture medium for diluting the pancreatin after the cell digestion is proper. And (4) blowing the digested cells into cell suspension by using a pipette, collecting the cell suspension into a centrifuge tube, and centrifuging at 1000rpm/min for 5 min.

Discarding the centrifuged supernatant, resuspending the cells in a mesenchymal stem cell serum-free medium, adjusting the proportion of the cells, and inoculating the cells into 150mm culture dishes, wherein each dish is cultured by 30mL of the medium. And when the cell fusion degree reaches 80%, collecting cells, and detecting the cell viability, cell phenotype, osteogenesis adipogenesis induced differentiation capacity and growth curve.

Comparative example 1 preparation of Primary umbilical cord mesenchymal Stem cells by conventional tissue Block adherence method

The difference from example 7 is that the medium for changing the medium in step (2) is a serum-free medium for mesenchymal stem cells, and the rest of the steps are the same as example 7.

TABLE 1

Serial number	Time for the degree of fusion of primary mesenchymal stem cells to reach 50% (d)
		Example 1	8
Example 2	9
		Example 3	11
Example 4	12
		Example 5	12
Example 6	13
		Comparative example 1	14

The morphology of the primary human umbilical cord mesenchymal stem cells in the methods of the examples and the comparative examples is observed under an inverted microscope, the primary cells grow adherently, and the morphology is long fusiform or polygonal. The fusion degree of the primary cells of the method is 50% on the 8 th day, while the fusion degree of the primary cells of the traditional tissue mass adherence method is only 10% on the 8 th day, and the fusion degree reaches 50% on the 15 th day.

Experimental example 1 detection of cell viability and cell phenotype

And (3) detecting the survival rate: take 2X 10⁵Adding PI reagent into each cell, mixing uniformly, and incubating in dark environment at 4 ℃. Then, physiological saline is added into each sample for constant volume, cells are washed, centrifugation is carried out, and supernatant is removed.

And (3) phenotype detection: 1) 9 samples were taken, each at 2X 10⁵Individual cells, marked blank, PerCP, PE, APC, FITC, isotype, phenotype, PE isotype and HLA-DR, respectively. 2) Adding corresponding reagents into samples of PerCP, PE, APC, FITC, homotypic, phenotype and the like, mixing uniformly, and incubating in dark environment at 4 ℃. Then, physiological saline is added into each sample for constant volume, cells are washed, centrifugation is carried out, and supernatant is removed. Resuspend each sample with saline. 3) And (4) analyzing by an up-flow cytometer, and directly measuring various phenotype results by using a surface type sample.

The specific test results are shown in FIGS. 1-7 and Table 2 below.

TABLE 2

Serial number

Rate of cell viability

CD90

CD105

CD73

CD14、CD34、CD20、CD45

HLA-DR

Example 1

98.19％

100.00％

99.71％

99.97％

0.55％

0.40％

Example 2

97.17％

99.68％

99.92％

99.95％

0.48％

0.66％

Example 3

96.44％

99.87％

99.79％

99.84％

0.80％

0.18％

Example 4

95.55％

99.89％

99.75％

99.96％

1.05％

0.87％

Example 5

94.27％

99.92％

99.64％

99.80％

0.69％

0.49％

Example 6

94.20％

99.66％

99.61％

99.70％

0.39％

0.18％

Comparative example 1

91.42％

98.69％

99.74％

99.84％

0.89％

0.12％

As can be seen from fig. 1-7 and table 2, the phenotypes of umbilical cord mesenchymal stem cells cultured according to the method of the present invention showed positive expression rates of CD90, CD105, and CD73 of 95% or more, positive expression rates of CD14, CD34, CD20, and CD45 of 2% or less, and positive expression rates of HLA-DR of 2% or less, which met the requirements. In addition, the umbilical cord mesenchymal stem cells cultured by the culture method are superior to cells cultured by a traditional method in cell viability.

Experimental example 2 cell adipogenic osteogenic induced differentiation experiment

1. Adipogenic induction and differentiation: collecting cells at 1X 10⁴Inoculating the cells into 24-well plate, adding appropriate amount of serum-free culture medium of mesenchymal stem cells, and standing at 37 deg.C in CO₂CO concentration of 5%₂Culturing in incubator, changing to adipogenic induction culture medium (GIBCO, A10071-01) on day 2, changing the culture medium every 3-4 days, washing with DPBS once on day 14, and fixing cells with 4% formaldehyde solution for 30 min. After fixation, the cells were washed 2 times with distilled water and stained with oil red O dye for 2-3 minutes. The test results are shown in FIG. 3, which is obtained by washing 3 times with distilled water, observing under an optical microscope and photographing.

2. Osteogenic induced differentiation: collecting cells at 1X 10⁴Inoculating the cells into 24-well plate, adding appropriate amount of serum-free culture medium of mesenchymal stem cells, and standing at 37 deg.C in CO₂CO concentration of 5%₂Culturing in incubator, changing to osteogenesis induction culture medium (GIBCO, A10071-01) on day 2, changing the culture medium every 3-4 days, washing with DPBS once on day 14, and fixing cells with 4% formaldehyde solution for 30 min. After fixation, the cells were washed 2 times with distilled water and stained with 2% alizarin red S solution (ph4.2) for 2-3 minutes. The test pieces were washed with distilled water 3 times, observed under an optical microscope and photographed, and the test results are shown in FIG. 4.

As shown in fig. 8 and 9, experiments of adipogenic and osteogenic induced differentiation of human umbilical cord mesenchymal stem cells cultured by the methods of different embodiments prove that the cells can grow adherently in a culture bottle or a culture dish under specific conditions in vitro, can differentiate into adipogenic and osteogenic cells, have the potential of differentiating into the adipogenic and osteogenic cells, and the cells cultured by the method of the invention are superior to the cells cultured by the conventional method in the adipogenic and osteogenic potential.

Experimental example 3 cell proliferation growth curve

Collecting cells at 1X 10⁴Inoculating the cells into a 24-well plate, adding a proper amount of the mesenchymal stem cell serum-free culture medium, taking three wells every 24 hours, adding 200 mu L of 0.05% pancreatin for digestion, and stopping digestion by 800 mu L of the mesenchymal stem cell serum-free culture medium. The counts were then averaged and recorded for 7 consecutive days.

As shown in FIG. 10, the growth curves of the human umbilical cord mesenchymal stem cells cultured by the methods of the different embodiments are similar in morphology, the cells are in the latent phase within 1-2 days and are not obviously proliferated, the cells enter the logarithmic growth phase within 3-5 days, the cell proliferation is accelerated, the cells enter the plateau phase after 6 days, the cell growth is stopped, and the growth curves of the umbilical cord mesenchymal stem cells cultured by the two methods are not obviously different.

The above are merely embodiments of the present invention, which are described in detail and with particularity, and therefore should not be construed as limiting the scope of the invention. It should be noted that, for those skilled in the art, various changes and modifications can be made without departing from the spirit of the present invention, and these changes and modifications are within the scope of the present invention.