Background: The testis is largely surrounded by an intrascrotal extension of peritoneal cavity (the processus vaginalis), which becomes the tunica vaginalis. Its visceral layer is opposed to the fibrous capsule of the testis, the tunica albuginea, and its parietal layer lines the most internal aspect of the scrotal wall. A small amount of fluid separates the visceral from the parietal layer. Each testis is covered by a dense irregular collagenous connective tissue capsule known as tunica albuginea that is rich in lymphatic endothelial cells. Deep to this layer is a highly vascularized loose connective tissue called tunica vasculosa which forms the vascular capsule of the testes. Tunica albuginea is thickened posteriorly to form mediastinum testis from which connective tissue septa subdivide testis into compartments called testicular lobules. Each lobule is occupied by one to four seminiferous tubules. Each seminiferous tubule is surrounded by loose connective tissue (interstitium) containing interstitial cells such as Leydig cells, fibroblasts, lymphocytes and macrophages. The seminiferous epithelium and the interstitium are separated by the basal lamina. Infertility is one of the important issues in medical science. A couple being unable to achieve pregnancy after one year of intercourse without the use of contraceptives can be considered infertile. Animal models are commonly used to study human infertility. The methods of creating infertility models include chemical, physical and endocrine factors. Chemical inducers include formaldehyde, gossypol) and BUS, The advantage of the BUS-induced sterile mouse model is the similarity between humans and animals regarding the dysfunction of reproductive system and infertility. BUS gives excellent results in cancer treatment, but it also produces numerous side effects, among which its toxicity on the reproductive system. It has inhibitory effects on cells with a high proliferation rate like spermatogonia, increases sperm abnormalities and oligo-azoospermia rate, decreases testicular weight and sperm motility, destroys testicular germ cells, and finally it causes temporary or permanent sterility.