Objective:To study the inhibitory effect of human embryonic stem cells on the HepG2 cells in vitro.Methods:The co-culture system of Human embryonic stem cells (H9) and liver cancer HepG2 cells was established.The effect of H9 on the biological behavior of HepG2 cells was observed by microscope,the flow cytometry was used to detcct the apoptosis of tumor cells and the cell cycle alteration.Transwell assay was used to detect the migration and invasion of tumor cells.Gene microarray technique was used to examine the change of gene expression profile of HepG2 cells.Results:In the process of co-culture,the growth of hepatoma cells was inhibited.With the extension of the culture time,cells decreased gradually,and occurred signs of aging or apoptosis.Flow cytometry test results showed that the apoptosis rate of hepatoma ceils was significantly increased,and the cell cycle was blocked in the G0/G1 phase.Transwell test results showed that the invasion and migration of HepG2 cells were decreased.The gene chip results showed that the whole genome expression profile of HepG2 cells had a significant change.Conclusion:The human embryonic stem cells had an inhibitory effect on HepG2 cells in vitro.

BACKGROUND:Swimming is an important non-pharmacological treatment for knee osteoarthritis,which can effectively alleviate the disease.However,the effect and mechanism of swimming on senile knee osteoarthritis are still unclear. OBJECTIVE:To investigate the effect of swimming exercise on the articular cartilage of aged mice with knee osteoarthritis. METHODS:Six 3-month-old male C57BL/6 mice were selected as the young group,and twelve 18-month-old male C57BL/6 mice were randomized into the aged group and the swimming group,with six mice in each group.Mice in the swimming group received adaptive swimming for 1 week and formal swimming for 8 weeks.After the intervention,stride length analysis and sampling were performed in each group.The total number of leukocytes and lymphocytes in peripheral blood was detected by blood routine examinations.The morphology of the articular cartilage was observed by hematoxylin-eosin and safranin O-fast green staining.Chondrocyte counts and the modified Mankin's score were used to evaluate the degree of articular cartilage damage.The protein and mRNA expressions of type Ⅱ collagen,aggrecan and matrix metalloproteinase 13 in articular cartilage were detected by immunohistochemical staining and RT-qPCR. RESULTS AND CONCLUSION:Compared with the young group,the mice in the aged group showed significantly decreased stride length(P＜0.05),significantly increased numbers of peripheral leukocytes and lymphocytes(P＜0.05),significantly decreased count of chondrocytes(P＜0.05),significantly increased modified Mankin's score(P＜0.05),significantly decreased protein and mRNA expression of type Ⅱ collagen and aggreca(P＜0.05),and significantly increased matrix metalloproteinase 13 expression(P＜0.05).Moreover,hematoxylin-eosin and safranin O-fast green staining showed the uneven surface of the articular cartilage,abnormal chondrocytes,and proteoglycan loss in the aged group.Compared with the aged group,swimming exercise significantly improved the stride length of mice(P＜0.05),decreased the count of peripheral blood lymphocytes(P＜0.05),increased the count of chondrocytes(P＜0.05),decreased the modified Mankin's score(P＜0.05),increased the protein and mRNA expression of type Ⅱ collagen and aggrecan(P＜0.05),and decreased the expression of matrix metalloproteinase 13(P＜0.05).Hematoxylin-eosin and safranin O-fast green staining showed that the articular surface of mice in the swimming group was smooth,chondrocytes were normal,and proteoglycan loss was less.All these findings indicate that swimming exercise can reduce the number of inflammatory cells in the blood of aged mice,improve articular chondrocytes,matrix composition and cartilage tissue morphology;thus,it has a protective effect on the cartilage of aged mice with knee osteoarthritis.