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目的探讨谷氨酰胺对脓毒症大鼠心肌胶原的保护机制。方法选健康18日龄Wistar大鼠121只,每个时间点随机取11只按腹腔注射药物不同分为：(1)生理盐水对照组(0h)；(2)内毒素(LPS)；(3)谷氨酰胺治疗(Gln)组。后两组又分为2、4、6、24及72 h时点。在各时点分离心脏,8只用逆转录-聚合酶链反应(RT-PCR)方法测定基质金属蛋白酶组织抑制因子3(TIMP-3) mRNA表达,另3只用于石蜡切片,用免疫组化方法测定金属心肌基质蛋白酶3(MMP-3)及其TIMP-3,以及用原位杂交方法测定MMP-3 mRNA表达。结果(1)LPS组各时点MMP-3及其mRNA表达较0h组增强,在6 h达高峰,到72h虽然有所下降仍高于对照组,P＜0．01；Gln组各时点MMP-3 mRNA及其蛋白质表达也较0 h组增强,但较LPS组各时点为弱,最高点在24 h,P＜0．01；(2)LPS组各时点TIMP-3以及mRNA表达较0 h组明显减弱,在6 h最低,P＜0．01；Gln组各时点TIMP-3以及mRNA表达也较0 h组减弱,但较LPS组为强,最低点在24 h,P＜0．01。(3)脓毒症组比Gln组心脏,超微结构改变明显。结论(1)在脓毒症时MMP-3及其mRNA表达增强,而TIMP-3及其mRNA表达受抑制。(2)谷氨酰胺可以减轻这种影响,而且使这种损伤作用时间向后推迟。
Objective To investigate the protective mechanism of glutamine on myocardial collagen in septic rats. Methods Twelve healthy 18-day-old Wistar rats were randomly divided into three groups: (1) saline control group (0h); (2) endotoxin (LPS); (3) ) Glutamine treatment (Gln) group. The latter two groups were divided into 2, 4, 6, 24 and 72 h time points. Hearts were isolated at different time points. Tissue samples were obtained from 8 of them by reverse transcription polymerase chain reaction (RT-PCR) and 3 of them were used for paraffin sections. Methods The levels of MMP-3 and TIMP-3 were measured and the expression of MMP-3 mRNA was determined by in situ hybridization. Results (1) The expression of MMP-3 and its mRNA at each time point in LPS group was higher than that in 0h group, reaching the peak at 6h, but still lower than that in control group at 72h (P <0.01) Compared with LPS group, MMP-3 mRNA and its protein expression increased at the same time point compared with that at 0 h group, but the peak was at 24 h (P <0.01). (2) TIMP-3 and mRNA Compared with 0 h group, the expression of TIMP-3 and mRNA in the Gln group was weaker than that in the 0 h group, but it was stronger than that in the LPS group, with the lowest point at 24 h, P <0.01. (3) Compared with Gln group, the ultrastructural changes in the sepsis group were obvious. Conclusions (1) The expression of MMP-3 and its mRNA is enhanced in sepsis and the expression of TIMP-3 and its mRNA is inhibited. (2) Glutamine can reduce this effect, but also postpones the timing of this damaging effect.