RESUMO
Growing evidence supports the role of gut microbiota in chronic inflammation, insulin resistance (IR) and sex hormone production in polycystic ovary syndrome (PCOS). Adropin plays a pivotal role in the regulation of glucose and lipid metabolism and is negatively correlated with IR, which affects intestinal microbiota and sex hormones. However, the effect of adropin administration in PCOS has yet to be investigated. The present study aimed to assess the effects of adropin on letrozole (LTZ)-induced PCOS in rats and the potential underlying mechanisms. The experimental groups were normal, adropin, letrozole and LTZ + adropin. At the end of the experiment, adropin significantly ameliorated PCOS, as evidenced by restoring the normal ovarian structure, decreasing the theca cell thickness in antral follicles, as well as serum testosterone and luteinizing hormone levels and luteinizing hormone/follicle-stimulating hormone ratios, at the same time as increasing granulosa cell thickness in antral follicles, oestradiol and follicle-stimulating hormone levels. The ameliorating effect could be attributed to its effect on sex hormone-binding globulin, key steroidogenic genes STAR and CYP11A1, IR, lipid profile, gut microbiota metabolites-brain-ovary axis components (short chain fatty acids, free fatty acid receptor 3 and peptide YY), intestinal permeability marker (zonulin and tight junction protein claudin-1), lipopolysaccharides/Toll-like receptor 4/nuclear factor kappa B inflammatory pathway and oxidative stress makers (malondialdehyde and total antioxidant capacity). In conclusion, adropin has a promising therapeutic effect on PCOS by regulating steroidogenesis, IR, lipid profile, the gut microbiota inflammatory axis and redox homeostasis. KEY POINTS: Adropin treatment reversed endocrine and ovarian morphology disorders in polycystic ovary syndrome (PCOS). Adropin regulated the ovarian steroidogenesis and sex hormone-binding globulin in PCOS. Adropin improved lipid profile and decreased insulin resistance in PCOS. Adropin modulated the components of the gut-brain-ovary axis (short chain fatty acids, free fatty acid receptor 3 and peptide YY) in PCOS. Adropin improved intestinal barrier integrity, suppressed of lipopolysaccharides/Toll-like receptor 4/nuclear factor kappa B signalling pathway and oxidative stress in PCOS.
RESUMO
Normal gonadal function can be disrupted by hypothyroidism. Hypothyroidism disturbs testicular function directly and centrally by affecting the hypothalamic-pituitary-testicular axis with unclear mechanism. As nesfatin-1 neurons co-localized with TRH and GnRH neurons in the hypothalamus, it could play a role in centrally hypothyroidism induced testicular dysfunction. Selenium (Se), by affecting thyroid iodide supply, could relieve these disturbances. So, we aim to identify the role of nesfatin-1 as a link between testicular dysfunction and hypothyroidism through modulating the MAPK/ERK pathway while discussing the possible role of Se in alleviating hypothyroidism and associated testicular damage. Forty male rats were divided equally into: Control: distilled water, Se: Se orally, Propylthiouracil (PTU): PTU orally, PTU + Se: Se with PTU orally. Serum thyroid function, gonadal hormones, nesfatin-1, testicular redox status, sperm analysis, brain tissue GnRH, nucleobindin 2-derived polypeptide, pMAPK/ERK gene expression, histological changes and immunohistochemical expression of testicular proliferating cell antigen (PCNA) were done. PTU induced hypothyroidism and reduction of gonadal hormones which both were correlated with reduced nesfatin-1. There was testicular stress with reduced GnRH, NUCB2, pMAPK/ERK gene expression, and PCNA immunopositive cells. These parameters were reversed by Se. Nesfatin-1 could be the central link between hypothyroidism and disturbances of the hypothalamic pituitary testicular axis.
