Background & objectives: According to importance of bone marrow mesenchymal stem cells in production of different cell lines, transplantation of these cells are used for treatment of many different diseases during cell therapy. Viability and proliferation of these cells after transplantation are very important. Since infertility is as public health problem in men and women, the scientists attempt to produce germ cells from differentiation of stem cells. It is supposed to use these cells for treatment of different illnesses especially for men with lack of germ cells in testes in future. However, in using stem cells for cell therapy the culture medium should be designed to increase the number of cells and efficiency of transplantation and to guarantee the health of the cells in terms of DNA damage. This study designed a suitable culture medium in order to increase the number of colonies and decrease the cell injuries.

Methods: In this study mesenchymal stem cells isolated from bone marrow of mice and exposed to retinoic acid (RA) with concentration of 10^-6 M and Sertoli cells condition medium. Since mesenchymal stem cells (MSCs) produce fibroblastic colonies so the number of colonies was counted every 3 days after culture (days of 2, 5, 8, 11, and 15) under inverted microscope. The staining of ethidium bromide-acridine orange was also done for determination of apoptotic nucleus in days of 10 and 15 after culture.

Results: The results showed that the effects of retinoic acid on grow and viability of MSCs is related to the time. It seems that RA increased the proliferation of the cells and the number of colonies increased in low time but the apoptotic cells elevated with increasing the time of culture. Condition medium of Sertoli cells also increased the proliferation of bone marrow stem cells.

Conclusion: According to proliferative properties of condition medium, it seems that using condition medium together with RA is better than RA alone for differentiation of MSCs to germ cells.