ABSTRACT
Photoaging refers to the accumulation of skin damage which includes wrinkle formation, loss of elasticity, and epidermal thickening due to repeated ultraviolet (UV) irradiation. The present study investigated the protective effects of Elaeagnus umbellata fruit extract (Elaea) on UV-mediated photoaged skin of SKH1 hairless mice and compared the effects of Elaea with ascorbic acid. Although there was no difference in body weight between groups during experimental period, oral administration of 50-200 mg/kg Elaea once daily for 15 weeks significantly prevented an increase in skin weight, epithelial thickening of epidermis, and apoptosis caused by UV irradiation. Skin replica and histopathological analyses revealed that Elaea dose-dependently decreased wrinkle and microfold formation. In addition, Elaea administration restored UV-mediated reduction in type I collagen and hyaluronan through the inhibition of matrix metalloproteinases and p38 mitogen-activated protein kinase expression. Moreover, Elaea suppressed UV-dependent increases in superoxide anion production, fatty acid oxidation, and protein nitration by up-regulating antioxidant system. Furthermore, Elaea alleviated infiltration of inflammatory cells in UV-irradiated skin. The preventive effects of 100 mg/kg Elaea administration against UV-induced photoaging were similar to those by 100 mg/kg ascorbic acid. Collectively, the present study suggests that the E. umbellata fruit is a promising edible candidate to prevent skin photoaging.
ABSTRACT
Chemokine ligand 2 (CCL2) binds to its receptor C-C chemokine receptor 2 (CCR2), initiating tissue inflammation, and recent studies have suggested a beneficial effect of a blockade of this pathway in diabetic nephropathy. To investigate the mechanism of protection, we studied the effect of RS504393, a CCR2 antagonist, on insulin resistance and diabetic nephropathy in db/db mice. Administering this antagonist improved insulin resistance as confirmed by various biomarkers, including homeostasis model assessment index levels, plasma insulin levels, and lipid abnormalities. Mice treated with the antagonist had a significant decrease in epididymal fat mass as well as phenotypic changes of adipocytes into small differentiated forms with decreased CCL2 expression and lipid hydroperoxide levels. In addition, treatment with the CCR2 antagonist markedly decreased urinary albumin excretion, mesangial expansion, and suppressed profibrotic and proinflammatory cytokine synthesis. Furthermore, the CCR2 antagonist improved lipid metabolism, lipid hydroperoxide, cholesterol, and triglyceride contents of the kidney, and decreased urinary 8-isoprostane levels. Hence, our findings suggest that CCR2 antagonists can improve insulin resistance by modulation of the adipose tissue and restore renal function through both metabolic and anti-fibrotic effects in type 2 diabetic mice.
