Dietary fluted pumpkin seeds induce reversible oligospermia and androgen insufficiency in adult rats.

Some components of the human diets are believed to be promising male contraceptive agents. The present study examined the antispermatogenic efficacy, reversibility and toxicity of fluted pumpkin seed-supplemented diet (DFPS) in adult male Wistar rats. Adult rats were given DFPS at 2.5, 5 and 10% for 60 days followed by 60 days post-treatment period. The control animals received normal standard rat diet not supplemented with fluted pumpkin seeds. The sperm quality variables, testosterone and follicle-stimulating hormone (FSH), oxidative status of the testis, steroidogenic enzymes and gamma-glutamyl transferase (γ-GT) activities and the histology of the testis were determined to evaluate the anti-fertility activity of fluted pumpkin seeds. Treatment of animals with DFPS at 5% and 10% resulted in decreased serum and intra-testicular testosterone and FSH concentrations. This effect was associated with decreased activity of 17β-hydroxysteroid dehydrogenase (17β-HSD), increased testicular oxidative stress and poor sperm quality in the 10% diet group. After 60 days DFPS post-treatment, intra-testicular 17β-HSD and γ-GT activities, FSH and testosterone levels recovered to control values. Furthermore, poor sperm motility, count, morphology and viability as well as severe loss of spermatogonia and other matured epithelial germ cells and Sertoli cells observed especially in the 10% DFPS-treated animals reverted to nearly control values 60 days after withdrawal of treatment. Dietary fluted pumpkin seeds may selectively act on the epithelial germ cells, possibly mediated via Sertoli cells, leading to oligospermia, oxidative damage and androgen insufficiency. The reversibility of these effects to near normal levels after withdrawal of treatment justifies further consideration of DFPS as it may be an effective and readily reversible agent that meets the required criteria of a male contraceptive agent. GC-MS: gas-chromatography mass spectrophotometry; MPO: myeloperoxidase; NO: nitric oxide; DFPS: dietary fluted pumpkin seeds; DFPS (REV): DFPS post-treatment; MDA: malondialdehyde; SOD: superoxide dismutase; CAT: catalase; GSH: glutathione; 3β-HSD: 3β-hydroxysteroid dehydrogenase; 17β-HSD: 17β-hydroxysteroid dehydrogenase; NAD: nicotinamide adenine dinucleotide (oxidized); NADH: nicotinamide adenine dinucleotide (reduced); ITT: intra-testicular testosterone; FSH: follicle-stimulating hormone; FPS: fluted pumpkin seeds; NIST: National Institute Standard and Technology; Av: absolute volume; Ac: cross-sectional area; ST: seminiferous tubules; γ-GT: gamma glutamyl transferase.