谷氨酰胺、地塞米松对脓毒症幼年大鼠小肠肿瘤坏死因子α与基质金属蛋白酶3的影响

Effects of Glutamine and Dexamethasone on Tumor Necrosis Factor Alpha and Matrix Metalloproteinase-3 of Small Intestine in Young Rat with Sepsis

目的观察在脓毒症时幼年大鼠小肠肿瘤坏死因子α(TNF-α)、基质金属蛋白酶3(MMP-3)的动态变化,探讨谷氨酰胺(Gln)、地塞米松(Dex)在这一病理过程中的作用。方法选健康18日龄Wistar大鼠128只,在设定时间点随机取8只,按腹腔注射药物不同分为生理盐水对照(0 h)、内毒素(LPS)、Dex和Gln治疗4组,后3组加LPS后于2、4、6、24及72 h分别取8只大鼠断头,分离远段回肠,石蜡包埋,固定,制成切片,用免疫组化方法测定TNF-α和MMP-3蛋白质表达。结果 (1)LPS组TNF-α蛋白质表达逐渐增高,24 h达高峰,各时点表达明显高于对照组(P<0.01);Dex组增高趋势明显比LPS组减弱,但各时点TNF-α表达仍明显高于对照组(P<0.01);Gln组6 h TNF-α表达显著高于LPS组(P<0.05);(2)LPS组MMP-3蛋白质表达与对照组比较明显升高,24 h达高峰,以后逐渐降低(P<0.01);Gln组各时点MMP-3表达均明显低于对照组(P<0.01);Dex组MMP-3蛋白质表达低于LPS组,但高于Gln组,各时点与对照组比较差异有统计学意义(P<0.01)。结论在抑制炎性介质方面地塞米松作用强于谷氨酰胺;地塞米松和谷氨酰胺都能减轻内毒素诱导的MMP-3的合成,但谷氨酰胺强于地塞米松。

Objective To observe the dynamic changes of tumor necrosis factor alpha（TNF-α） and matrix metalloproteinase-3（MMP-3） of small intestine in young rats with sepsis and to investigate the effects of dexamethasone（Dex） and glutamine（Gln） on them.Methods 128 Wistar rats with 18 days of age were intraperitoneally injected with normal saline（8 rats）,LPS（40 rats,4 mg/kg,Escherichia coli O55：B5）,Dex（40 rats,LPS 4 mg/kg 1 hour late＋ Dex 5 mg/kg） and Gln（40 rats,LPS 4 mg/kg ＋ Gln 1 ml/kg）,respectively.They were then sacrificed after 0,2,4,6,24 and 72 hours,and distal segments of ileum were collected,paraffin-embedded and fixed to measure the expressions of TNF-α and MMP-3 by immunohistochemistry.Results 1.Expression of TNF-α in LPS group gradually increased with the progression of the disease and reached the peak at 24 h,and was significantly higher versus control group at each time point（P 〈 0.01）.In Dex group,this tend was less obvious,but expression of TNF-α at each time point was still significantly higher（P 〈 0.01）.Expression of TNF-α was significant higher in Gln group versus LPS group at 6 h（P 〈 0.05）.2.Similar to TNF-α,expression of MMP-3 in LPS group also gradually increased with the progression of sepsis and reached the peak at 24 h,and was significantly higher than that in control group（P 〈 0.01 except at 6 h）.However,expression of MMP-3 in Gln group was significantly lower（P 〈 0.01 except at 6 h）.Expression of MMP-3 in Dex group was higher than Gln group but lower versus LPS group,and was significantly higher versus control group at each time point（P 〈 0.01）.Conclusion 1.The inhibiting effect of Dex on inflammation was stronger than that of Gln.2.Both Dex and Gln had inhibiting effects on MMP-3 synthesis induced by LPS,but effect of Glu was stronger.