谷氨酰胺对内毒素血症大鼠肠道损伤的保护作用及对血红素加氧酶-1表达的影响

目的 探讨谷氨酰胺(Glu)对内毒素血症大鼠肠道损伤的保护作用以及对血红素加氧酶-1(HO-1)表达的影响.方法 按随机数字表法将32只雄性SD 大鼠分为正常对照组、模型组、Glu组和Glu+锌原卟啉(ZnPP)组,每组8只.腹腔注射内毒素脂多糖(LPS)10 mg/kg制备内毒素血症动物模型.Glu组注射LPS前12 h灌胃Glu 1 g/kg;Glu+ZnPP组注射LPS前12 h灌胃Glu 1 g/kg,注射LPS前1 h静脉注射ZnPP 10 mmol/kg.术后12 h取回肠组织,测定髓过氧化物酶(MPO)活性及肿瘤坏死因子-α(TNF-α)、白细胞介素-10(IL-10)含量,并进行肠组织学评分;用免疫组化法检测回肠组织HO-1表达.结果 与正常对照组比较,模型组回肠组织学评分、MPO活性及TNF-α、IL-10含量显著升高组织学评分(分):3.3±0.4比1.1±0.6,MPO活性(U/g):0.40±0.08比0.26±0.07,TNF-α含量(ng/g):25.2±6.9比6.5±2.8,IL-10含量(ng/g):27.6±10.2比5.7±2.9,均P<0.01];HO-1表达较低.与模型组比较,Glu组组织学评分、MPO活性和TNF-α含量明显减低组织学评分(分):1.6±0.5比3.3±0.4,MPO活性(U/g):0.25±0.05比0.40±0.08,TNF-α含量(ng/g):13.4±3.2比25.2±6.9,均P<0.01],IL-10含量(ng/g)显著升高(47.3±5.5比27.6±10.2,P<0.01),HO-1表达明显增加.Glu+ZnPP组与模型组各指标比较差异无统计学意义.结论 Glu能明显增强内毒素血症大鼠肠组织HO-1表达,明显减轻肠道炎症反应,从而保护肠黏膜.

Abstract：

Objective To investigate the protective effect of glutamine (Glu) pretreatment on intestinal injury induced by endotoxin and expression of heme oxygenase-1 (HO-1) in rats.Methods Thirty-two male Sprague-Dawley (SD) rats were randomly divided into four groups (n=8 in each group): normal control group, model group, Glu group and Glu+zinc protoporphyrin (ZnPP) group. In model group, endotoxemia was produced by intraperitoneal injection of lipopolysaccharide (LPS, 10 mg/kg). In Glu group, the rats received intragastraiclly 1 g/kg of Glu 12 hours before LPS intraperitoneal injection. In Glu+ZnPP group, the rats received 1 g/kg of Glu by gavage 12 hours before LPS intraperitoneal injection and ZnPP 10 mmol/kg intravenously via tail vein 1 hour before LPS injection. The distal ileum was harvested in full thickness 12 hours after LPS injection. The myeloperoxidase (MPO) activity, tumor necrosis factor-α (TNF-α) and interleukin-10 (IL-10) in the intestine were determined, the pathologic changes were observed and expressed in Chiu grade. The expression of HO-1 was evaluated by immunohistochemistry method. Results Compared with normal control group, the Chiu grade, MPO activity, the content of TNF-α and IL-10 were significantly increased in model group Chiu grade: 3.3±0.4 vs. 1.1±0.6, MPO activity (U/g): 0.40±0.08 vs. 0.26±0.07, TNF-α (ng/g): 25.2±6.9 vs. 6.5±2.8, IL-10 (ng/g): 27.6±10.2 vs. 5.7±2.9, all P<0.01], and the expression of HO-1 was decreased. Compared with model group, the Chiu grade, MPO activity, the content of TNF-α in Glu group were significantly decreased Chiu grade: 1.6±0.5 vs. 3.3±0.4, MPO activity (U/g): 0.25±0.05 vs. 0.40±0.08, the content of TNF-α (ng/g): 13.4±3.2 vs. 25.2±6.9, all P<0.01], while the level of IL-10 (ng/g) elevated (47.3±5.5 vs. 27.6±10.2, P<0.01), and the expression of HO-1 was increased. There was no difference in above mentioned indexes between model group and Glu+ZnPP group. Conclusion Glu pretreatment significantly ameliorates the expression of HO-1 of intestinal tissue induced by LPS in rats, and intestinal mucosa is protected with alleviation of inflammatory reaction in intestinal tract.

The protective effect of glutamine on endotoxemic intestinal injury and expression of heme oxygenase-1 in rats

Objective To investigate the protective effect of glutamine (Glu) pretreatment on intestinal injury induced by endotoxin and expression of heme oxygenase-1 (HO-1) in rats.Methods Thirty-two male Sprague-Dawley (SD) rats were randomly divided into four groups (n=8 in each group): normal control group, model group, Glu group and Glu+zinc protoporphyrin (ZnPP) group. In model group, endotoxemia was produced by intraperitoneal injection of lipopolysaccharide (LPS, 10 mg/kg). In Glu group, the rats received intragastraiclly 1 g/kg of Glu 12 hours before LPS intraperitoneal injection. In Glu+ZnPP group, the rats received 1 g/kg of Glu by gavage 12 hours before LPS intraperitoneal injection and ZnPP 10 mmol/kg intravenously via tail vein 1 hour before LPS injection. The distal ileum was harvested in full thickness 12 hours after LPS injection. The myeloperoxidase (MPO) activity, tumor necrosis factor-α (TNF-α) and interleukin-10 (IL-10) in the intestine were determined, the pathologic changes were observed and expressed in Chiu grade. The expression of HO-1 was evaluated by immunohistochemistry method. Results Compared with normal control group, the Chiu grade, MPO activity, the content of TNF-α and IL-10 were significantly increased in model group Chiu grade: 3.3±0.4 vs. 1.1±0.6, MPO activity (U/g): 0.40±0.08 vs. 0.26±0.07, TNF-α (ng/g): 25.2±6.9 vs. 6.5±2.8, IL-10 (ng/g): 27.6±10.2 vs. 5.7±2.9, all P<0.01], and the expression of HO-1 was decreased. Compared with model group, the Chiu grade, MPO activity, the content of TNF-α in Glu group were significantly decreased Chiu grade: 1.6±0.5 vs. 3.3±0.4, MPO activity (U/g): 0.25±0.05 vs. 0.40±0.08, the content of TNF-α (ng/g): 13.4±3.2 vs. 25.2±6.9, all P<0.01], while the level of IL-10 (ng/g) elevated (47.3±5.5 vs. 27.6±10.2, P<0.01), and the expression of HO-1 was increased. There was no difference in above mentioned indexes between model group and Glu+ZnPP group. Conclusion Glu pretreatment significantly ameliorates the expression of HO-1 of intestinal tissue induced by LPS in rats, and intestinal mucosa is protected with alleviation of inflammatory reaction in intestinal tract.