The Effect of Stem Cell Factor and Retinoids in Spermatogonial Cell Differentiation of Testicular Tissue of Obstructive Azoospermia Model Adult Rats

Retinoids and stem cell factor play an important role in the stem cells proliferation, survival, and differentiation into sperm. Therefore, in this study, the effect of stem cell factor and retinoids on the proliferation and differentiation of spermatogonial cells in testis seminiferous tubules of obstructive azoospermia model adult rats was investigated using the tissue culture system. The testicular tissue fragments were cultured in the culture medium supplement with retinoids or stem cell factor, or a combination of both at the temperature of 34.5 °C and 5% CO2 for 25, 30, and 35 days. Then, the stained tissue sections prepared at the mentioned times were evaluated using PAS and hematoxylin staining methods. The cell counting per unit area was done using ImageJ software, and the statistical analysis was performed by one-way ANOVA and Tukey's post hoc test. The number of spermatogonia, spermatocyte, and Leydig cells increased significantly on day 25, 30 and 35 of culture; additionally, the number of round and elongated spermatid increased significantly on day 35 of culture in the testicular tissue of the obstructive azoospermia compared to the experimental and control groups (p < 0.001). Histological examination of testicular tissue in different culture conditions revealed pathological changes in the epithelialmaking cells. Retinoids played a more effective role on day 35 of culture compared to other factors in maintaining and proliferation of cell lines of the spermatogenesis process. As these factors are not alone the cause of proliferation and differentiation induction, therefore optimizing the culture medium is recommended to achieve adult sperm.