BACKGROUND
Infertility is a serious social problem in advanced nations, with male factor in half of all cases of infertility. This study was conducted to determine the regenerative effect of bone marrow-derived stem cells in spermatogenesis of infertile hamster.
METHODS
Twelve adult male hamsters were equally divided into azoospermic and control groups. Busulfan was intraperitoneally used for induction of azoospermia, while the right testis was treated with bone marrow-derived stem cells (106 BM-SCs), labeled with sterile trypan blue, 35 days after busulfan injection. The left testis served as positive control for azoospermia. Sixty days after cell transplantation, the animals were euthanized and both testes were removed and evaluated histologically.
RESULTS
BM-SCs were spindle-shaped, adherent to the culture flasks. Alcian blue staining confirmed differentiation of BM-SCs into chondrocytes. Karyotyping denoted to stability of chromosomes. Treatment with busulfan in seminiferous tubules resulted into distruption of spermatogenesis. After two months in busulfan treatment group, seminiferous tubular atrophy and germinal epitheliums degenerations were noticed with no spermatozoa in epididymis. After treatment of busulfan group with BM-SCs, spermatogonia, primary spermatocytes, spermatids and sperms were present in seminiferous tubules. 
CONCLUSION
As cell transplantation in seminiferous tubules resulted into a rapid repair of pathological changes, BM-SCs can be recommended an effective treatment measure in azoospermia. It seems that more studies are necessary to confirm the use of this technique in treatment of azoospermia and infertility in human.