Abstract:

Abstract:Objective
To isolate and cultivate human bone marrow mesenchymal stem cells (hMSCs) in vitro,and observe the  expression of alternative lengthening telomere related promyelocytic leukemia protein (PML) in hMSCs,in order to evaluate its role in self-renewal and division growth processes of hMSCs.Methods hMSCs were isolated from bone marrow by Percoll density gradient centrifugation.Immunocytochemistry staining was used to detect the expression rate of PML body in hMSCs.Results There were no visible expressions of PML body in passage 1,3 and 5 of cultured hMSCs.There was positive expression of PML body in passage 7 hMSCs,there were brown particles in nuclei of hMSCs,the positive rate was (16.1±0.6）%.There were also positive expressions of PML body in passage 9 and 11  hMSCs,the positive rates were (16.8±2.6)% and (45.8±9.5)%, respectively;there were significant differences between passage 9,11 and passage 7  hMSCs（P＜0.05）.Conclusion Following long-time culture of hMSCs in vitro,ALT will appear in hMSCs to promote the lengthening of telomere,and maintain the ability of proliferation and self-renewal of hMSCs.

Key words: bone marrow;mesenchymal stem cell； telomerase；immunohistochemistry