脂多糖注射剂量与注射方式对家兔炎症反应及回肠形态结构的影响

Effects of injection dose and injection method of lipopolysaccharide on ileum morphology and systemic inflammatory response in rabbits

为了探究脂多糖的注射剂量和注射方式对家兔炎症反应及回肠形态结构的影响,试验将70只体重相近的40日龄健康家兔随机分成7组,分别为对照组和J1、J2、J3、F1、F2、F3组,每组10个重复,每个重复1只,对照组肌肉注射1 mL生理盐水,J1、J2、J3组分别按体重50,100,200μg/kg肌肉注射1 mL脂多糖,F1、F2、F3组分别按体重50,100,200μg/kg腹腔注射1 mL脂多糖,分别于注射0,4,8,12,16,20,24小时时在家兔直肠处测量体温;并于注射24 h后对各组进行静脉采血,测定血清中的肿瘤坏死因子(TNF-α)、白细胞介素1β(IL-1β)和白细胞介素6(IL-6)的含量;安乐死后,采集回肠肠段,进行H.E.染色,对各组回肠形态结构进行观察,同时进行肠道病变评定,最后测定各组回肠绒毛高度、绒毛宽度和肠黏膜厚度。结果表明:注射50~200μg/kg脂多糖对家兔体温有不同程度的影响,其中J3、F3组在注射脂多糖4,12,16,20,24小时时体温均显著高于对照组(P<0.05);但除J2组在注射脂多糖4 h和24小时时体温显著高于F2组外,其余不同注射方式同等注射剂量两组间体温差异不显著(P>0.05)。注射脂多糖24小时时,J2组、F2组、J3组和F3组血清TNF-α、IL-1β和IL-6含量均显著高于对照组(P<0.05),J1组和F1组的血清TNF-α、IL-1β和IL-6含量与对照组差异不显著(P>0.05);在同等注射剂量不同注射方式下,两组间的血清TNF-α、IL-1β和IL-6含量均差异不显著(P>0.05)。注射脂多糖24小时时,各组回肠均出现了不同程度的损伤;随着注射剂量的增加,损伤程度逐渐增大,淋巴细胞数量和吸收细胞空泡化情况逐渐增多;但在同等注射剂量下,不同注射方式两组间肠道损伤程度、淋巴细胞数量和吸收细胞空泡化情况差异不明显;肠道病变评定对照组为优,J1组和F1组为良,J2组和F2组为较差,J3组和F3组为差。F1组、J2组、F2组、J3组和F3组回肠绒毛高度、绒毛宽度和黏膜厚度均显著低于对照组(P<0.05),J1组回肠绒毛高度和绒毛宽度显著低于对照组(P<0.05)。说明注射100~200μg/kg脂多糖可以引起家兔发生较为严重的炎症反应及肠道损伤,而不同注射方式同等注射剂量对家兔回肠形态结构的影响不大。

To explore the effects of injection dose and injection method of lipopolysaccharide on ileum morphology and systemic inflammatory response in rabbits,seventy 40-day-old healthy rabbits with similar body weight were randomly divided into seven groups,which were control group and J1,J2,J3,F1,F2 and F3 groups with ten replicates per group and one rabbit per replicate.The control group was intramusculally injected with 1 mL normal saline.J1,J2 and J3 groups was intramuscularly injected 1 mL lipopolysaccharide at body weight of 50,100 and 200μg/kg.F1,F2 and F3 groups were intraperitoneally injected with 1 mL lipopolysaccharide at body weight of 50,100 and 200μg/kg,respectively.Body temperature was measured in the rectum of rabbits at 0,4,8,12,16,20 and 24 h after injection,and blood samples were collected intravenously at 24 h after injection.The contents of TNF-α,IL-1βand IL-6 in serum were determined.After euthanasia,ileum segments were collected and treated with H.E.The morphology and structure of ileum in each group were observed by staining,and the intestinal lesions were evaluated at the same time.Finally,the villus height,villus width and intestinal mucosal thickness of ileum in each group were measured.The results showed as follows:Lipopolysaccharide injection of 50-200μg/kg had different effects on the body temperature of rabbits.The body temperature of J3 and F3 groups was significantly higher than that of control group after 4,12,16,20,24 h of lipopolysaccharide injection(P<0.05).However,the body temperature of J2 group was significantly higher than that of F2 group after injection of lipopolysaccharide at 4 h and 24 h,and there was no significant difference in body temperature between the two groups with different injection methods and the same dose(P>0.05).At 24 h of LPS injection,the contents of TNF-α,IL-1βand IL-6 in serum in groups J2,F2,J3 and F3 were significantly higher than those in control group(P<0.05),but the contents of TNF-α,IL-1βand IL-6 in serum in groups J1 and F1 were not significantly different from those in control group(P>0.05).At 24 h after LPS injection,the ileum of each group showed different degrees of injury.With the increase of injection dose,the degree of injury,the number of lymphocytes and vacuolization of absorptive cells gradually increased.However,with the same injection dose,there was no significant difference in the number of lymphocytes and vacuolization of absorptive cells between the two groups with different injection methods.The intestinal lesions were evaluated as excellent in control group,good in J1 and F1 groups,poor in J2 and F2 groups,and very poor in J3 and F3 groups.The villus height,villus width and mucosal thickness of ileum in F1,J2,F2,J3 and F3 groups were significantly lower than those in control group(P<0.05),and the villus height and villus width of ileum in J1 group were significantly lower than those in control group(P<0.05).The results suggested that lipopolysaccharide injection at 100-200μg/kg could cause serious inflammatory reaction and intestinal injury in rabbits,while the same injection dose in different injection methods had little effect on the morphology and structure of the intestine in rabbits.