肥胖女性与体重正常女性内脏和皮下脂肪组织水通道蛋白7表达水平的比较

Comparison of different expression of aquaporin 7 in subcutaneous and visceral adipose tissue between obese and normal weight women

目的从mRNA水平及蛋白水平观察水通道蛋白7(aquaporin 7,AQP7)在肥胖女性及体重正常女性内脏脂肪组织及皮下脂肪组织中的表达差异,探讨AQP7与肥胖关系。方法采用荧光实时定量PCR方法和Western blot方法测定肥胖组(女性,8例),体重正常组(女性,8例,简称正常组)的内脏及皮下脂肪组织AQP7mRNA表达水平与AQP7蛋白含量,并采用改良比色法测定两组血清甘油及游离脂肪酸(FFA)浓度。结果 (1)无论肥胖组还是正常组,内脏脂肪AQP7蛋白(664.67±353.82)的表达量显著多于皮下脂肪(18.41±14.21)(P<0.01);肥胖组的内脏脂肪AQP7蛋白含量较正常组升高67%(P>0.05),肥胖组的皮下脂肪AQP7蛋白含量较正常组升高1倍(P>0.05)。(2)荧光实时定量PCR测得肥胖组内脏脂肪AQP7mRNA表达量较正常组升高53%(P>0.05),肥胖组皮下脂肪AQP7mRNA表达量较正常组升高86%(P<0.05),两组内比较皮下脂肪与内脏脂肪AQP7mRNA表达无差异。(3)肥胖组较正常组胰岛素抵抗指数升高,但两组间血清甘油与FFA水平差异无统计学意义。两组间AQP7mRNA、AQP7蛋白表达与血清甘油、FFA水平无相关性。结论女性内脏脂肪组织AQP7蛋白含量显著高于皮下脂肪组织,肥胖者皮下及内脏脂肪的AQP7mRNA及AQP7蛋白含量较体重正常者增高。研究揭示AQP7在肥胖的发生发展中起一定作用,可能通过内脏脂肪AQP7的作用参与胰岛素抵抗。

Objective To evaluate the gene expression of aquaporin 7 in subcutaneous adipose tissue （ SAT） and visceral adipose tissue （VAT） of obese and normal weight women. Methods Subcutaneous and visceral adipose tissue were obtained from sixteen women, 8 normal subjects （BMI 18.5-22.9 kg/m^2 ） and 6 obese subjects （≥25.0 kg/m^2） with benign tumor undergoing abdominal surgery. AQP7 mRNA expression was measured by real time PCR and the AQP7 protein expression by Western blotting. Serum levels of fasting glycerol and free fatty acid （FFA） were measured by Kits. Results （1） The AQP7 protein expression showed a significant increase in VAT （664.67± 353.82） than in SAT（18.41 ± 14.21） （P〈0.01）. Obese women showed a higher AQP7 protein expression than did normal weight women not only in VAT （increased by 100%, P=0.086） but also in SAT （increased by 67%, P=0.056）. （2） AQP7 mRNA expression was higher in obese subjects than in normal BMI patients not only in VAT （ increased by 86%, P〈0.05） but also in SAT （increased by 53%, P=0. 160）. And no significant difference in AQP7 mRNA gene expression levels was showed between VAT and SAT in same group of obesity or normal BMI. （3） The insulin resistance index was significantly higher in the obese than in the normal BMI group, and but there were no differences in the serum glycerol and FFA level between these two groups. Conclusions The AQP7 gene is differentially expressed between subcutaneous and visceral adipose tissue. The AQP7 protein expression is obviously higher in VAT than in SAT. The expressions of AQP7 mRNA and protein are higher in obese subjects than in normal BMI subjects in both VAT and SAT. It suggests AQP7 may have a crucial role in obesity generation and may induce the insulin resistance through visceral adipose.