Sertoli cell-conditioned medium restores spermatogenesis in azoospermic mouse testis

The current study evaluates potential applications of Sertoli cell (SC)-conditioned medium (CM) and explores the effects of the conditioned medium on the spermatogenesis process in azoospermic mice. For this study, 40 adult mice (28-30 g) were divided into 4 experimental groups: (1) control, (2) DMSO 2% (10 μl), (3) busulfan (40 mg/kg single dose) and (4) busulfan/CM (10 μl). SCs were isolated from 4-week-old mouse testes. After using anesthetics, 10 μl of CM was injected over 3-5 min into each testis and subsequently, sperm samples were collected from the tail of the epididymis. Afterward, the animals were euthanized and testis samples were taken for histopathology experiments and RNA extraction in order to examine the expression of c-kit, STRA8 and PCNA genes. The data showed that CM notably increased the total sperm count and the number of testicular cells, such as spermatogonia, primary spermatocytes, round spermatids, SCs and Leydig cells compared with the control, DMSO and busulfan groups. Furthermore, the results showed that expression of c-kit and STRA8 was significantly decreased in the busulfan and busulfan/SC groups at 8 weeks after the last injection (p < 0.001) but no significant difference was found for PCNA compared with the control and DMSO groups (p < 0.05). These findings suggest that the Sertoli cell-conditioned medium may be beneficial as a practical approach for therapeutic strategies in reproductive and regenerative medicine.