糖尿病慢性期肾一氧化氮合酶在糖尿病肾病中的作用

Role of renal nitric oxide synthase in diabetic kidney disease during the chronic phase of diabetes.

作者信息

Khamaisi Mogher, Keynan Shoshana, Bursztyn Michael, Dahan Rachel, Reinhartz Etti, Ovadia Haim, Raz Itamar

机构信息

Department of Internal Medicine B, Diabetes Center, Hadassah University Hospital, Jerusalem, Israel.

出版信息

Nephron Physiol. 2006;102(3-4):p72-80. doi: 10.1159/000089946. Epub 2005 Nov 25.

DOI:10.1159/000089946

PMID:16319502

Abstract

BACKGROUND

Several studies have suggested that an early increase in renal nitric oxide (NO) production or activity mediates pathophysiologic and morphologic changes in diabetic nephropathy. To evaluate the role of NO in developing diabetic kidney disease, we studied the NO system in streptozotocin (STZ)-induced diabetic rats for a period of 8 weeks.

METHODS

Control rats, STZ-induced diabetic rats, and STZ-induced diabetic rats treated with insulin were monitored and sacrificed at 1, 2, and 8 weeks. Urinary cGMP was measured, and the levels and activity of NO synthase (NOS) isoforms in the kidney cortex were determined at specific times by immunoblotting and diaphorase staining.

RESULTS

Diabetic rats had increased kidney weight, urinary volume, glucose, sodium and potassium excretion, which was precluded by insulin treatment. Creatinine clearance was increased in the diabetic group and reversed by insulin treatment. Urinary cGMP decreased by 71, 93, and 92% at 1, 2, and 8 weeks of diabetes, respectively, compared with the control animals. Insulin treatment curtailed the urinary cGMP reduction in diabetic animals. Total NOS activity in the renal cortex was reduced by 65, 52, and 44% after 1, 2, and 8 weeks of diabetes, respectively, and returned to normal levels upon insulin treatment. NADPH diaphorase staining of renal cortical slices showed a 77, 63, and 70% decrease in neuronal NOS isoform activity in the macula densa after 1, 2, and 8 weeks of diabetes, respectively, compared with control non-diabetic animals. This reduction was normalized by insulin treatment. Endothelial NOS protein expression in the kidney cortex tended to increase after 1 week of diabetes and its level was elevated significantly after 2 and 8 weeks of diabetes. However, neuronal NOS protein expression in the kidney cortex was reduced by 52% in 2-week diabetic animals, but this reduction was normalized by insulin treatment.

CONCLUSIONS

The decreased renal NOS activity during the late phase of diabetes is partially associated with a decrease in neuronal NOS activity and protein expression in kidney macula densa.

摘要

背景

多项研究表明，糖尿病肾病中早期肾脏一氧化氮（NO）生成或活性增加介导了病理生理和形态学改变。为评估NO在糖尿病肾病发展中的作用，我们对链脲佐菌素（STZ）诱导的糖尿病大鼠的NO系统进行了为期8周的研究。

方法

对正常对照大鼠、STZ诱导的糖尿病大鼠以及接受胰岛素治疗的STZ诱导的糖尿病大鼠在第1、2和8周进行监测并处死。检测尿cGMP水平，并在特定时间通过免疫印迹和黄递酶染色测定肾皮质中NO合酶（NOS）同工型的水平和活性。

结果

糖尿病大鼠肾脏重量、尿量、葡萄糖、钠和钾排泄增加，胰岛素治疗可阻止这些变化。糖尿病组肌酐清除率增加，胰岛素治疗可使其恢复正常。与对照动物相比，糖尿病1、2和8周时尿cGMP分别降低71%、93%和92%。胰岛素治疗可减少糖尿病动物尿cGMP的降低。糖尿病1、2和8周后，肾皮质总NOS活性分别降低65%、52%和44%，胰岛素治疗后恢复至正常水平。与对照非糖尿病动物相比，糖尿病1、2和8周后肾皮质切片的NADPH黄递酶染色显示致密斑中神经元NOS同工型活性分别降低77%、63%和70%。胰岛素治疗可使这种降低恢复正常。糖尿病1周后肾皮质中内皮型NOS蛋白表达有增加趋势，糖尿病2周和8周后其水平显著升高。然而，糖尿病2周动物肾皮质中神经元NOS蛋白表达降低52%，但胰岛素治疗可使其恢复正常。