灯盏花素对糖尿病大鼠神经肽Y及受体影响

Effect of breviscapine on neuropeptide Y and its Y_2 receptor expression in streptozotocin-induced diabetic rats

目的探讨灯盏花素治疗糖尿病肾病(DN)的机制。方法大鼠随机分为正常对照组,糖尿病组和灯盏花素干预组,以链脲佐菌素复制糖尿病模型;采用放射免疫法检测神经肽Y含量,逆转录-聚合酶链反应(RT-PCR)和免疫组织化学方法分别检测肾皮质神经肽Y mRNA和Y2受体蛋白表达,大鼠血糖、尿白蛋白排泄率(UAER)、肾皮质Na+,K+-ATPase活性。结果灯盏花素干预组大鼠血糖〔(20.02±2.89)mmol/L〕、UAER〔(1.03±0.19)μg/min〕明显低于糖尿病组(P<0.01),血浆和肾皮质神经肽Y浓度分别为(4.453±0.245)ng/mL、(0.66±0.08)ng/mg,肾皮质Na+,K+-ATPase活性为(3.29±0.80)μmol Pi/mg.pro,明显低于糖尿病组(P<0.05);与糖尿病组比较,灯盏花素干预组大鼠肾皮质神经肽Y mRNA和Y2受体表达分别降低了30.2%,26.3%(P<0.05)。结论灯盏花素可通过下调肾皮质神经肽Y及Y2受体表达,抑制肾皮质Na+,K+-ATPase活性,改善DN。

Objective To investigate the regulatory mechanism of breviscapine to neuropeptide Y（NPY） and its Y2 receptor（Y2R） in diabetic nephropathy.Methods The male Wistar rats were randomly allocated to three groups：normal control,streptozotocin-induced diabetes,and diabetes treated with breviscapine group.After 28 days,the rats were sacrificed.The level of NPY in plasma and renal cortex,the urine albumin excretion ratio（UAER） were measured with radioimmunoassay（RIA）.RT-PCR,immunohistochemistry（IHC）,and computer software for image analysis were used to evaluate the expression of NPY mRNA and Y2R.Blood glucose,body weight,kidney weight,and Na＋,K＋-ATPase activity were measured.Results Compared with diabetes mellitus group,the blood glucose（20.02±2.89 mmol/L） and UAER（1.03±0.19 μg/min） of diabetic rats were ameliorated by breviscapine treatment.Compared with diabetes mellitus group,the plasma and renal cortical NPY concentrations（4.453±0.245 ng/mL and 0.66±0.08 ng/mg） and Na＋,K＋-ATPase activity（3.29±0.80 μmol Pi/mg protein/hr） were significantly decreased in breviscapine treatment group（P0.05）.The expressions of NPY mRNA and Y2R protein were significantly decreased to 30.2% and 26.3% in the renal cortex of diabetic rats treated with breviscapine compared with that of diabetic rats（P0.05 for both）.Conclusion Breviscapine can down-regulate expressions of NPY mRNA and Y2R,then inhibit Na＋,K＋-ATPase activity in renal cortex and therefore improve the damage in diabetic nephropathy.