基于EGC研究大建中汤对肠易激综合征内脏痛模型大鼠的改善作用

Study on the Improvement Effects of Dajianzhong Decoction on Irritable Bowel Syndrome Visceral Pain Model Rats Based on EGC

目的:研究大建中汤对肠易激综合征(IBS)内脏痛模型大鼠的改善作用及其机制。方法:将48只雄性未断乳大鼠随机分为正常对照组、模型组、匹维溴铵组(阳性对照,45 mg/kg)和大建中汤高、中、低剂量组(2.16、1.08、0.54 g/kg,以生药总量计),每组8只。除正常对照组外,其余各组大鼠经母子分离、乙酸灌肠、卵清白蛋白腹腔注射等复制IBS内脏痛模型,造模共57 d。第58天,给药组大鼠灌胃相应药物,模型组和正常对照组大鼠灌胃等体积水,每日1次,连续14 d。观察各组大鼠一般情况;采用腹壁撤退反应(AWR)评估各组大鼠在20、40、60、80 mmHg(1 mmHg=0.133 kPa)压力下的内脏敏感性;采用苏木精-伊红染色方法观察各组大鼠结肠组织病理学特征;采用Western blotting技术检测结肠组织中肠胶质细胞标志物纤维酸性蛋白(GFAP)和神经生长因子(NGF)及其受体酪氨酸蛋白激酶A(TrkA)蛋白的表达情况。结果:正常对照组大鼠结肠组织未见明显病理学改变。模型组大鼠结肠组织黏膜不连续,腺体水肿,固有层内散在分布淋巴细胞、中性粒细胞和嗜酸性粒细胞;大建中汤低剂量组大鼠结肠组织黏膜不完整,部分腺体轻度水肿,固有层内有少量淋巴细胞和中性粒细胞;大建中汤中、高剂量组和匹维溴铵组大鼠结肠黏膜上皮结构完整,腺体排列规则,未见变性坏死和炎症细胞浸润。与正常对照组比较,模型组和大建中汤低剂量组大鼠20、40、60 mmHg压力下的AWR评分和结肠组织中GFAP、NGF、TrkA蛋白的相对表达量均显著升高(P<0.05或P<0.01)。与模型组比较,大建中汤中、高剂量组和匹维溴铵组大鼠20、40 mmHg压力下的AWR评分,大建中汤高剂量组和匹维溴铵组大鼠60 mmHg压力下的AWR评分,大建中汤中、高剂量组和匹维溴铵组大鼠结肠组织中GFAP、NGF、TrkA蛋白的相对表达量均显著降低(P<0.05或P<0.01)。结论:大建中汤可能通过抑制肠胶质细胞活化、减少NGF和TrkA的表达,进而改善IBS模型大鼠的内脏痛。

OBJECTIVE:To study the improvement effect and mechanism of Dajianzhong decoction on irritable bowel syndrome(IBS)visceral pain model rats.METHODS:Totally 48 male non-weaning rats were randomly divided into normal control group,model group,pinaverium bromide group(positive control,45 mg/kg)and Dajianzhong decoction high-dose,medium-dose and low-dose groups(2.16,1.08,0.54 g/kg,by crude drug),with 8 rats in each group.Except for normal control group,IBS visceral pain model was established by mother and child separation,acetic acid enema,ovalbumin intraperitoneal injection in other groups for 57 d.On the 58 th day,the rats in administration groups were given the corresponding drugs intragastrically,and model group and normal control group were given constant volume of purified water,once a day,for consecutive 14 d.The general condition of rats was observed;abdominal wall withdrawal reaction(AWR)was adopted to evaluate the visceral sensitivity of rats in each group under 20,40,60,and 80 mmHg(1 mmHg=0.133 k Pa)pressure;HE staining method was used to observe the colon pathological features of rats in each group.Western blotting assay was used to detect the protein expression of intestinal glial cells markers fibrillary acidic protein(GFAP),nerve growth factor(NGF)and its receptor TrkA in colon tissue.RESULTS:The mucosal layer of colon tissue in rats of model group was discontinuous,gland edema was observed and lymphocytes,neutrophils and eosinophils were scattered in the lamina propria.In Dajianzhong decoction low-does group,the mucosal layer of colon tissue was incomplete,some glands were slightly edematous,and a few lymphocytes,neutrophils in the lamina propria.The colonic mucosa epithelial structure was intact,glands arranged regularly,and no degenerative necrosis and inflammatory cells were observed in Dajianzhong decoction medium-and high-dose groups and pinaverium bromide group.Compared with normal control group,AWR scores under 20,40,and 60 mmHg pressure,relative protein expression of GFAR,NGF and TrkA were all increased significantly in model group and Dajianzhong decoction low-does groups(P<0.05 or P<0.01).Compared with model group,AWR scores under 20,and 40 mmHg pressure in Dajianzhong decoction medium-and high-dose groups and pinaverium bromide group,AWR scores under 60 mmHg pressure in Dajianzhong decoction high-dose group and pinaverium bromide group,relative protein expression of GFAP,NGF,TrkA in colon tissue in Dajianzhong decoction medium-and high-dose groups and pinaverium bromide group were all decreased significantly(P<0.05 or P<0.01).CONCLUSIONS:Dajianzhong decoction could improve the visceral pain of IBS model rats by inhibiting the activation of intestinal glial cells and reducing the expression of NGF and TrkA.