谷氨酰胺对内毒素性休克大鼠糖皮质激素受体的保护作用

Protective effect of glutamine on expression of glucocorticoid receptor in endotoxic shock rats

目的探讨内毒素性休克时糖皮质激素受体(GR)表达量的变化及谷氨酰胺(Gln)对其的保护作用。方法18只健康雄性SD大鼠,随机分成内毒素(LPS)休克组,Gln预处理组和空白对照组,每组6只。空白对照组及LPS注射后6h处死三组大鼠,取各组大鼠心、肝、肺、肾、主动脉组织,用Westernblot方法观察各脏器上GR和热休克蛋白(HSP)70的表达。结果空白对照组心、肝、肺、肾、主动脉仅有少量HSP70的表达。与空白对照组比较,LPS休克组各脏器HSP70的表达量显著增高(P<0.05)。Gln预处理组HSP70的表达量较LPS休克组进一步增加(P<0.05)。LPS休克组GR蛋白的表达分别降低至空白对照组的71%(心脏),8%(肝脏),38%(肺脏),17%(肾脏),23%(主动脉);预处理Gln后上述脏器的GR蛋白表达的减少得以显著恢复(P<0.05)。结论内毒素性休克时GR蛋白表达量减少。应用Gln可部分改善内毒素性休克时GR蛋白的下调,此作用与其诱导HSP70的表达有关。

Objective To observe the effect of glutamine（Gln）on protein expression of glucocorticoid receptor（ GR） in endotoxic shock rats. Methods Eighteen healthy male Sprague-Dawley rats were randomly divided into control group（n = 6）, escherichia coil LPS-induced shock group （n = 6）, and Gln pretreated group（n= 6）. All rats were killed 6 h after LPS injection and multiple tissues of heart,liver,lung,kidney,and aorta were harvested. The protein expression of GR and heat shock protein 70（HSP70）were assayed with Western blot. Results The expression of HSP70 was low in the heart, liver,lung,kidney and aorta in control group. The expressions were significantly higher in LPS group than those in control group（P〈0. 05）. The expression of HSP70 was further enhanced in Gln pretreated group than that in LPS group. In comparison with the control group,the protein expression of GR in LPS group decreased by 71% in the heat,8% in the liver,38% in the lung,17% in the kidney and 23% in the aorta in LPS group（P〈0.05）, However,the decreases were significantly reversed in Gln pretreated group（P〈0. 05）. Conclusion The down-regulation of the protein expression of glucocorticoid receptor in endotoxic shock rats was partly reversed by pretreatment with Gln. The protective mechanism of Gln may be related to its inductive HSP70 expression.