Expression of tumor necrosis factor-α in visceral adipose tissue of non-obesity rats with insulin resistance

Objective To investigate the expression and location of tumor necrosis factor(TNF)-α in the visceral and subcutaneous adipose tissues of non-obesity rats with insulin resistance.Methods Insulin-resistant rat model(IR group,n=10)was reproduced with 6 to 8-week-old Sprague-Dawley(SD)rats by high-glucose diet(70% calories from glucose)for 12 weeks.Normal diet SD rats(n=10)were used as a control(CN group).The levels of TNF-α protein and TNF-α mRNA in the visceral and subcutaneous adipose tissues were assayed by immunohistochemistry and RT-PCR methods.Results TNF-α positive staining was found in the intercellular substance of the visceral and subcutaneous adipose tissues.There was no TNF-α staining in the adipocytes themselves.The levels of TNF-α protein and TNF-α mRNA in the visceral adipose tissue in IR group were significant higher than those in CN group(both P0.01).The levels of TNF-α protein and mRNA in the subcutaneous adipose tissue of IR group rats were similar to that in the CN group(both P0.05).Conclusion TNF-α is over-expressed in the intercellular substance of visceral adipose tissue of non-obesity rats with high-glucose diet-induced insulin resistance.(Shanghai Med J,2008,31:788-791)