谷氨酰胺对脓毒症大鼠脑功能的保护作用

Protective effects of glutamine on brain function in septic rats

目的观察谷氨酰胺(Gln)对脓毒症大鼠脑功能的保护作用及可能机制。方法 SD大鼠73只随机分为四组:假手术组(S组,n=13)、脓毒症组(C组,n=20)、Gln治疗组(G组,n=20)、槲皮素干预组(Q组,n=20)。C、G和Q组采用盲肠结扎穿孔术(CLP)复制脓毒症模型。S组仅行腹腔开关术。S组和C组术后给予生理盐水5～7ml静脉缓慢泵入;G组和Q组静脉输注Gln0.75g/kg(换算为4%丙二酰-谷氨酰胺5～7ml)静脉缓慢泵入,Q组术后即刻腹腔注射热休克蛋白(HSP)合成抑制剂槲皮素400mg/kg。四组大鼠持续监测术后即刻(0h)、术后2、6、10、16h的MAP和HR,术后24h行神经反射评分后断颈处死,取出脑组织测定脑组织含水量、半胱氨酸蛋白酶-3(caspase-3)含量和热休克蛋白70(HSP70)的表达。结果术后16h时C、G、Q组大鼠MAP明显低于术后0h时和S组(P<0.05)。C组大鼠HR在术后6和10h时明显快于、在术后16h时明显慢于术后0h和S组(P<0.05)。Q组大鼠HR在术后6和10h时明显快于术后0h(P<0.05)。与S组比较,C组神经反射评分、脑组织含水量和caspase-3含量明显升高(P<0.05),G、Q组神经反射评分、脑组织含水量明显升高(P<0.05)。与C组比较,G组神经反射评分、脑组织含水量和caspase-3含量明显降低,Q组神经反射评分、脑组织含水量明显降低(P<0.05)。Q组神经反射评分、脑组织含水量和caspase-3含量较G组有部分回升,且脑组织含水量和caspase-3含量明显高于G组(P<0.05)。C、G组HSP70表达明显高于S组,且G组明显高于C组和Q组(P<0.05)。结论 Gln诱导HSP70表达增加对脓毒症大鼠脑功能有一定保护作用。

Objective To investigate the protective effects of glutamine on brain function in septic rats and the possible mechanism. Methods Seventy-three male SD rats were randomly divided into 4 groups： Sham-operation group（group S, n=13）, Sepsis group （group C, n=20）, Glutamine therapy group（group G, n=20）, and Quercetin intervention group （group Q, n= 20）. The cecum ligation operation perforation （CLP） was performed in Groups C, G and Q to induce sepsis. Rats in Group S only had abdominal opening and closing. Rats in Groups C and S were injected with 5-7 ml of saline intravenously after operation, whereas those in groups G and Q received 0.75 g/kg of Gin. Group Q also received 400 mg/kg of quercetin （ip）, an inhibitor of heat shock protein synthesis, right after CLP was performed. MAP and HR were monitored continuously at 0,2,6,10,16 h after surgery in all groups. The rats received neural reflex score assessment 24 h postoperatively and were sacrificed afterwards. Brain tissues were extracted to determine water content, Caspase-3 level and heat shock protein 70 （HSP70） expression level. Results At 16 h after surgery in groups C,G,Q of MAP was lower than that at 16 h after surgery and groups S（P〈0.05）. The rats in group C HR at 6 h and 10 h after surgery is obviously faster than that, when 16 h after surgery was slower than that at 0 h after surgery and groups S （P〈0.05）. The rats in group Q HR at 6 h and 10 h after surgery significantly faster than that at 0 h after surgery （P〈0.05）. Compared with group S, at 16 after surgery, increased the neural reflex score, upregulated the percentage of brain water content, and induced the expression levels of caspase-3 and HSP70 in brain at 16 h after surgery （group C）. Gln （group G） significantly inhibited the above changes, except that the HSP70 expression level was further increased compared to group C. Quercetin significantly downregulated brain HSP70 levels and partly reversed all the other changes induced by Gin （group Q）. Conclusion The Gln exerts cerebral protective effects in septic rats by inducing HSPT0 expression.