Improvement of insulin sensitivity by osteocalcin inhibits inflammation in the adipose tissue of obese mice / 中国病理生理杂志

ABSTRACT

AIM:To explore the improving effect of osteocalcin on obesity-related insulin resistance and in-flammation in the adipose tissue of obese mice .METHODS:The C57BL/6 mice were fed with high-fat diet for 12 weeks to obtain obese mice.Osteocalcin (30 ng/kg or 3 ng/kg) and saline solution (control) were intraperitoneally injected for other 4 weeks.The fat mass, body weight, serum triglycerides and serum free fatty acid were analyzed .Intraperitoneal glu-cose tolerance test and insulin tolerance test were carried out .Macrophage infiltration degree in the adipose tissue was ob-served by immunohistochemical staining .The mRNA expression of monocyte chemotactic protein-1 ( MCP-1 ) and CD68 was detected by real-time fluorescence quantitative PCR .RESULTS:Osteocalcin (30 ng/kg or 3 ng/kg) treatment for 4 weeks significantly reduced the body weight , fat mass and insulin level , and improved abnormal glucose tolerance and insu-lin resistance in the obese mice .Moreover, the macrophage infiltration decreased , and the mRNA expression of MCP-1 and CD68 was down-regulated in the adipose tissue of obese mice treated with osteocalcin at 30 ng/kg.CONCLUSION:Os-teocalcin at 30 ng/kg significantly reduces body weight and fat mass , and attenuates the severity of insulin resistance through down-regulating the mRNA expression of MCP-1 and CD68 and inbihiting macrophage infiltration in the adipose tis-sue of obese mice induced by high-fat diet.