2型糖尿病大鼠膀胱M_3受体改变的实验研究

Alteration of M_3 subtype muscarinic receptors in type 2 diabetic rat urinary bladder

目的研究病程3周的2型糖尿病大鼠膀胱M3受体含量及其基因转录水平的变化情况,探讨糖尿病性膀胱早期发病机制中逼尿肌M3受体的改变情况。方法2 d龄雌性Wistar大鼠随机分成2型糖尿病组和正常对照组,链脲佐菌素按90 mg/kg体重腹腔注射并结合高糖高脂饮食诱导2型糖尿病大鼠模型。于糖尿病病程3周时进行下列实验:反转录-聚合酶链反应(RT-PCR)方法检测M3受体mRNA的含量;Western blotting方法检测膀胱M3受体蛋白的含量。结果RT-PCR方法检测结果显示:糖尿病组大鼠膀胱M3受体mRNA的数量显著高于正常对照组[(52.0±5.7)%vs(35.6±11.7)%,P<0.05]。Western blotting方法检测结果显示:糠尿病组大鼠膀胱M3受体含量显著高于正常对照组[(30.9±2.1)%vs(23.4±4.7)%,P<0.01]。结论本研究证实了糖尿病性膀胱早期M3受体的生物合成上调这一改变,从而解释了糖尿病早期膀胱逼尿肌收缩力增加这一现象。这可能是早期糖尿病性膀胱病变的一个发病机制。

Objective To research into the alteration of M3 subtype musearinic receptors in diabetic cystopathy （DCP）, and the alterations in M3 subtype musearinic receptor protein quantity and biosynthesis in the 3-week type 2 diabetic rat urinary bladder：Methods Two-day-old female Wistar rats were divided into two groups： type 2 diabetic rats and normal control rats. The type 2 diabetic ram were induced by the intraperitoneal injection of streptozotocin （STZ） （90 mg/kg） and high energy diet. When diabetes meUitus was developed on 3-weeks, the alteration of M3 subtype muscarinic receptors in m（s bladder was studied. M3 musearinic receptor mRNA in bladder tissue was determined using RTPCR method. The amount of M3 receptor protein in rat bladder body tissue was measured by Western blotting method. Results The results of RT-PCR showed that the amount of M3 musearinie receptor mRNA in the 3-week diabetic rat bladder was increased than the control bladder [ （52.0 ± 5.7） % vs （35.6 ± 11.7） % , P 〈 0.05 ]. Western blotting demonstrated that the amount of M3 musearinic receptor protein in 3-week diabeitc rat bladder was increased than control bladder [ （30.9 ±2.1 ） % vs （ 23.4 ± 4.7） %, P 〈 0.01 ]. Conclusion These findings demonstrate an upregulation of M3 subtype muscarinie receptors biosynthesis in the diabetic urinary bladder. This phenomenon offers an explanation of the increased contractility after musearinie stimulation of the detrusor muscle of diabetic animals. It is thought that the alteration of M3 subtype musearinie receptors is one of the merehanisms of early stage DCP.