The effects of melatonin administration in determined times of day on the kidney in rats with high-calorie diet-induced obesity

Abstract

Kidneys, like the cardiovascular system, are one of the main target organs, the most vulnerable to obesity, because the first take on the metabolism correction function at an increasing excess of fat tissue in the body. Kidney affection under obesity is a multifactorial thing that is caused by a number of processes, including inflammation, oxidative stress, lipid metabolism disorders, renin-angiotensin-aldosterone system activation, insulin resistance and other factors. An optimal candidate for reducing the harmful effects of kidneys obesity should be a compound that simultaneously exhibits anti-inflammatory and antioxidant properties, controls the circadian rhythm, and also affects on the adipokines secretion. The molecule that meets these conditions is melatonin.The aim of our study was to determine morpho-functional state (morphology characteristic of kidney glomeruli and tubules; morphometric parameters: area and density of glomeruli) of kidney in rats with high-calorie (high fat) diet-induced obesity after melatonin administration in determined time of the day. Melatonin was administered daily by gavage for 7 weeks in dose 30 mg/kg 1 h before lights-off (ZT11) rats with high-calorie diet (HCD). Rats with HCD had huge changes in kidney morphology, which manifested in presence of numerous mesangial cells outside glomeruli and lipid droplets in tubules epithelial cells, while area and density of glomeruli in cm2 decrease. In general kidney with above mentioned characteristic from HCD rats lose their ability to conduct strongly renal function. After melatonin used in rats with HCD arise leveling of pathological changes, which associated with consumption of HCD. Namely, in rats with development obesity melatonin administrations led to increase area and density in comparison to HCD group, moreover glomeruli density reach control values. This is suggest that melatonin have protecting effect against glomerular degeneration. In conclusions, melatonin influence on kidney morpho-functional state in rats with HCD and turn back pathological its changes, moreover evening administration can use for obesity therapy via its strong action on conservation glomerular morphology.