Vitamin E improves testicular damage in streptozocin‐induced diabetic rats,via increasing vascular endothelial growth factor and poly(ADP‐ribose) polymerase‐1

The precise mechanism by which diabetes impairs spermatogenesis and testicular function is not exactly known. Vascular endothelial growth factor (VEGF) and poly(ADP‐ribose) polymerase‐1 (PARP‐1) are important for germ cell homeostasis and repair of DNA respectively. The aim of this study was to investigate the correlation between diabetes‐induced testicular damage and testicular VEGF and PARP‐1 expression and the possible protective role of vitamin E supplementation. A total of 45 male Wistar albino rats were randomly divided into three groups: Group I (nondiabetic rats), Group II (streptozocin‐induced diabetic rats) and Group III (streptozocin‐induced diabetic rats treated orally with 0.4 mg/kg vitamin E). Five weeks later, testicular tissue was used for assessment of MDA concentration by colorimetry, histopathological examination and immunostaining for PARP‐1 and VEGFIn diabetic rats, testicular weight, seminiferous tubule diameter and germinal epithelial thickness were decreased, basement membrane was thickened and Johnsen score decreased. Reduced VEGF and PARP‐1 immunostaining were associated with decreased Johnsen score in diabetic rats. Vitamin E administration was protective against oxidative stress‐associated damage evidenced by lower MDA levels, improved testicular weight, spermatogenesis and higher immunostaining for VEGF and PARP‐1. Testicular VEGF and PARP‐1 might therefore be helpful biomarkers for diabetic testicular damage. Administration of vitamin E may have a protective role against diabetes‐induced testicular damage.