Objective- Perturbation of the normal process of testicular descent results in the condition of cryptorchidism. Spermatogenesis is generally impaired in cryptorchid testes because of high intratesticular temperature. It seems that the main mechanisms underlying the process of spermatozoa demise is apoptosis by overgeneration of free radicals. So, the aim of the present study was to investigate the effects of zinc sulfate as a potent antiapoptic and antioxidant agent on histopathological changes of rat testes after experimental cryptorchidism.
Design- Experimental study
Animals- Forty five male adult Sprague–Dawley rats
Procedures-  Animals were divided into three experimental groups each containing fifteen rats. Control group (Con) which did not undergo any surgical procedure. Animals in the first treatment group (Cry, cryptorchid operated group without any treatment) were rendered unilaterally cryptorchid in the left testes  without any drug administration. Rats in the second treatment group (Zth, cryptorchid operated group with zinc therapy) were rendered unilaterally cryptorchid in the left testes and treated with 10 mg/kg zinc sulfate every other day for 60 days. The control and treated animals were sacrificed on days 15, 30 and 60 after operation and both testes were removed for histopathological evaluations. 
Results- Cryptorchidism (Cry group) caused a complete depletion of spermatozoa from the lumen of seminiferous tubules and zinc administration (Zth group) could not improve spermatogenesis and meiotic index except slightly for meiotic index at 60 days compared with the control group (1.21 ± 0.009 vs. 3.38 ± 0.014, P<0.05). Induction of cryptorchidism significantly decreased the diameter and epithelial height of seminiferous tubules compared to the control group and also affected contralateral (right) testes (P<0.05). However administration of zinc (Zth group) significantly improved the epithelial height in each evaluated time points. Although a significant decrease in the mean diameter of spermatogonia and sertoli cells were observed at each evaluated time points post operation (P<0.05) but zinc therapy significantly increased the mean diameter of spermatogonia cells from 30 days and improved the mean diameter of sertoli cells from 15 days post operation compared with the Cry group in ipsilateral testes (5.13 ± 0.05 vs. 4.69 ± 0.05 and 28.84 ± 0.71 vs. 23.17 ± 0.29, respectively). In contralateral testes, all  above mentioned parameters were affected and zinc therapy significantly improved them (P<0.05).
Conclusion and clinical relevance- These finding clearly demonstrates that zinc is able to decrease detrimental effects of cryptorchidism on spermatogonia and sertoli cells and improves spermatogenesis process specially in contralateral (scrotal) testes. Therefore it may be useful for treatment of cryptorchidism outcomes in male animals.