Histological observation of leptin receptor in skeletal muscle in obese rats with periodontitis

To invesitgate the protein expression for leptin receptor in skeletal muscle in periodontitis and obese rat models, with the aim of exploring the effect of experimental periodontitis on adipokines receptors in insulin-targeting tissues and underlying mechanisms of skeletal muscle insulin resistance.

Forty natal SD male rats were randomly divided into four groups, respectively: obese rats with periodontitis (OB+ CP group), obese rats without periodontitis (OB group), normal rats with periodontitis (CP group) and normal rats without periodontitis (C group). Obese rat model was established by subcutaneous injection of sodium glutamate. Experimental periodontitis was induced by ligation and inoculation of periodontal pathogens. Immunohistochemical analysis of leptin receptor expression in skeletal muscle of four groups was employed.

In the skeletal muscle, the protein for leptin receptor in the C group and CP group were popular and strong positive, and there was no statistically significant difference between the groups (P > 0.05). The protein expressions in the OB + CP group and OB group were decreased. Fewer protein expression was detected in the OB + CP group when compared with OB group (P < 0.05). A synergistic interaction between obesity and periodontitis was evident to the expression for the leptin receptor (P < 0.05). Local infection induced by experimental periodontitis can barely down-regulate the protein expression for leptin receptor in the skeletal muscle. However, periodontitis can significantly down-regulate the protein expressions with the presence of obesity.