The effects of sericin in recovering spermatogenesis and sexual hormone levels in diabetic rats.

Abstract

Sericin-S (a hydrolysate from the silk protein sericin) is a natural antioxidant, which may improve spermatogenesis while having high biological safety, thus potentially useful for the treatment of male infertility. Our objective was to determine the effects of sericin-S on the sperm parameters and sexual hormone levels in a diabetic rat model. Thirty-six adult male rats were randomly divided in two groups, inducing diabetes in one of them by intraperitoneal administration of streptozotocin (STZ; 65mg/kg). Both groups were randomly assigned to three subgroups, receiving oral gavage of saline, 1% or 2% sericin extract for 60days. Therefore, the experimental design was a 2 × 3 factorial design of STZ and sericin treatments. One day after the last treatment, the rats were euthanized, weighed, the testes were processed (weigh, volume, and histology), and serum samples were processed for measuring sex hormone levels [testosterone, follicle-stimulating hormone, and luteinizing hormone (LH)]. STZ treatment decreased LH concentration and counts of spermatogonia, spermatocytes, and spermatids. Body and testis weights were significantly (p < 0.05) lower in the control group (non-diabetic saline) compared to the treated groups. In non-diabetic rats, sericin treatments increased (p < 0.05) the number of testicular cells (spermatogonia, spermatocytes, spermatids, Sertoli, and Leydig cells) and sex hormone concentrations. In diabetic rats, administration of sericin significantly (p < 0.05) improved sperm cell number and sex hormones levels. In nutshell, sericin can clearly modify sperm parameters and overall sex hormone function, and could improve spermatogenesis in normal and diabetic rats.