Therapeutic effect of bone marrow mesenchymal stem cells for treatment of induced mild testicular degeneration in dogs

Bone marrow-derived mesenchymal stem cells (BM-MSCs) are extensively used in regenerative medicine. The present work was aimed at investigating the effect of autologous BM-MSCs on semen characteristics and the blood flow of testes associated with hormonal levels of testosterone in testicular degeneration in stray dogs with induced mild heat stress by scrotal insulation. Ten stray male dogs were used in the study, which were exposed to mild heat stress (HS) through padding of the scrotum with a wool-blend sock for 96 h. Then, the dogs (n=10) were randomly distributed into 2 groups; group one (n=5; CON) was injected with 1 ml of phosphate-buffered saline (PBS) once in each testicle and considered as control, whereas group two (n=5; BM-MSCs) was injected intra-testicularly with autologous bone marrow MSCs once for each testicle (1 ml of PBS containing the harvested MSCs) 3 weeks following HS induction. Testicular haemodynamics and semen pictures were determined at weeks 0, 2, 4, 6, 8 and 10 in both groups. The results showed that the dogs treated with autologous BM-MSCs had higher end diastolic velocity (EDV) and and peak systolic velocity (PSV) values (P<0.05) between 6th to 10th week following injection than those before treatments. However a significant (P<0.05) decrease in resistance index (RI) and pulsatility index (PI) values was also noticed from the 4th until the 10th week. The single intra-testicular injection of autologous BM-MSCs resulted in significantly (P<0.05) increased sperm cell concentration, motility %, and live and normal spermatozoa, where the maximum value appeared after 10 weeks post-treatment of dogs as compared to day 0 and to the control dogs. Serum levels of testosterone and nitric oxide (NO) were significantly higher (p<0.05) in BM-MSCs-treated group from the 2nd week until the 10th week following injection than those before treatment and in the control group. In conclusion, this study demonstrates the effectiveness of the autologous BM-MSCs treatment in increasing sperm concentration, motility % and also improving testicular blood flow besides levels of testosterone and NO. Further studies are needed to validate these findings.