L-精氨酸对宫内发育迟缓大鼠肾脏Pax2表达的影响

Effect of L-arginine on Pax2 expression in the kidneys of pup rats with intrauterine growth retardation

摘要:

目的：研究L-精氨酸（L-Arg）对宫内发育迟缓(IUGR)大鼠肾脏 Pax2表达的影响。方法：孕鼠随机分为 3 组：正常对照组、IUGR 组和干预组。正常对照组母鼠全程以普通饲料（含 21％ 蛋白）喂养。IUGR 组和干预组大鼠孕期均采用低蛋白饲料（含 10% 蛋白）喂养。仔鼠出生后，IUGR 组母鼠常规饲料喂养；干预组母鼠在常规饲料喂养的基础上，于部分饮水中每日添加 L-Arg 200 mg/kg。取 7 d、21 d、2月和 3月龄仔鼠肾脏组织，用免疫组化和 Western blot 法检测 Pax2 表达。结果：免疫组化显示正常对照组仔鼠在各时间点均未见明显 Pax2 表达。IUGR 组、干预组仔鼠2月龄和 3月龄时，两组大鼠在肾小球和肾小管区可见 Pax2 阳性细胞，且 3月龄鼠的 Pax2 表达比 2月龄的更显著（P<0.05）；干预组的 Pax2 表达低于同龄IUGR组（P<0.05）。Western blot 检测发现，3 组仔鼠肾脏在 7 d 和 21 d 均未见 Pax2 蛋白明显表达。到 2月龄和 3月龄时，干预组和 IUGR 组仔鼠肾组织 Pax2 蛋白表达均较正常对照组显著增多，但干预组的表达低于 IUGR 组（P＜0.01）。结论：IUGR 大鼠成年后肾脏 Pax2 基因有再表达现象；用L-Arg 干预后Pax2 表达明显减少。

Abstract:

OBJECTIVE: To study the effect of L-arginine (L-Arg) on Pax2 expression in the kidneys of pup rats with intrauterine growth retardation (IUGR). METHODS: Pregnant rats were randomly assigned into three groups：normal, IUGR and L-Arg treated IUGR. The rats in the normal group were fed with ordinary forage (21% protein) during pregnancy. Those in the other two groups were fed with low diet forage (10% protein) during pregnancy. The L-Arg treated group was given drinking water containing L-Arg (200 mg/kg) daily during 21 days of lactation. Pax2 expression in renal tissues was measured with immunohistochemical staining and Western blot in pup rats of 7 days, 21 days, 2 months and 3 months old. RESULTS: The immunohistochemical staining showed that Pax2 was not expressed in the pup rats from the normal group at any time point. Pax2 positive cells were found in renal glomerulus and kidney tubules of 2-months- and 3-months-old rats from the IUGR and L-Arg treated groups. And Pax2 expression in 3-months-old rats was significantly higher than that in 2-months-old rats (P<0.05). L-Arg treatment decreased significantly the Pax2 expression in 2-months- and 3-months-old rats when compared with the untreated IUGR group (P<0.05). Western blot showed that Pax2 protein was not expressed in 7-days- and 21-days-old pup rats from three groups. Pax2 protein expression in 2-months- and 3-months-old pup rats from the IUGR and L-Arg treated groups increased significantly compared with normal controls. Pax2 protein expression in the pup rats from the L-Arg treated group was significantly lower than that in the untreated IUGR pup rats (P<0.01). CONCLUSIONS: Pax2 is expressed in the kidneys of IUGR rats during adulthood. L-Arg treatment can decrease the expression of Pax2.