The GDNF/GFRα1 signaling pathway plays a major role in the maintenance of undifferentiated SSCs, and their over-expression leads to accumulation of clusters of undifferentiated spermatogonia and testicular tumors.6,32 In the current study, the expression level of GFRα1 was increased in the treated groups when compared with the control group (Figs. 4 and 5). This evidence concerns the gene GDNF and neoplasm of testis.