Effect of high-fructose diet-induced metabolic syndrome on the pituitary-gonadal axis from adolescence through adulthood in male albino rats and the possible protective role of ginger extract. A biochemical, histological and immunohistochemical study.

Abstract

This work was designed to clarify, for the first time up to our knowledge, the effects of high-fructose diet (HFrD)-induced metabolic syndrome (MetS) on the pituitary-gonadal axis of adolescent male rats continuing through adulthood period and to evaluate the possible role of ginger extract in ameliorating these effects. Forty 4-week-old male albino rats, treated for 8 weeks, were randomly divided into four equal groups; control (fed standard diet), ginger extract-treated (500 mg/kg once daily orally by gavage), HFrD-induced MetS (fed a diet containing 60% fructose), HFrD and ginger groups. The assessment methods included biochemical, histological and immunohistochemical studies. High-fructose diet-fed rats exhibited a picture similar to MetS in the form of increased body weight and serum levels of glucose and insulin with an elevated HOMA-IR reflecting insulin resistance as well as dyslipidaemia. Lipid peroxidation (increased malondialdehyde) and oxidative stress (decreased superoxide dismutase) were implicated in this syndrome. This group exhibited a significant decrease in testicular weight and the levels of reproductive hormones (LH, FSH and testosterone). The pituitary gonadotrophs showed electron dense nuclei, large cytoplasmic vacuoles, destructed organelles in addition to decreased number of secretory granules. Furthermore, testicular specimens presented marked alterations. There were disorganised shrunken tubules with irregular basement membranes, reduced germinal epithelial thickness, vacuolations and degenerated mitochondria in the spermatogenic cells. Beclin 1 and proliferating cell nuclear antigen immunoexpressions were significantly downregulated with HFrD-induced MetS. Ginger extract supplementation proved to be a potent protective agent against these harmful effects through its antioxidant, hypoglycaemic, insulinotropic, androgenic and hypolipidaemic effects in addition to its ability to induce testicular autophagy. Consumption of HFrD induced MetS and proved to have harmful effects on the pituitary-testicular axis. Moreover, this work provided a new insight into the possible use of ginger extract to alleviate the main features of MetS and protect the pituitary-gonadal axis from the damaging effects of HFrD-induced MetS.