强冷应激对阿勒泰羔羊血清IgG、皮质醇及小肠免疫相关细胞的影响

Effect of severe cold stress on serum IgG,cortisol concentration and intestinal immune-related cells in Altay lambs

为了探讨较强寒冷刺激对阿勒泰羔羊血清IgG和皮质醇含量的影响及小肠黏膜免疫屏障的适应特征。把阿勒泰羔羊置于-30～-35℃分别进行0,6 h、1,4,12,24 d的冷刺激,利用酶联免疫吸附试验(ELISA)对阿勒泰羔羊血清中IgG和皮质醇的含量进行测定;通过石蜡切片和HE染色对阿勒泰羔羊小肠的显微结构进行观察;并通过改良甲苯胺蓝染色鉴定小肠中的甲苯胺蓝染色阳性细胞。发现冷应激后IgG质量浓度都比正常组明显降低,其中冷应激4 d与正常组质量浓度差异极显著(P<0.01),冷应激后皮质醇质量浓度比正常组表达上升,其中冷应激6 h时与正常组差异显著(P<0.05),而24 d与正常组差异极显著(P<0.01);IgG与皮质醇浓度在4,12和24 d呈较强正相关,6 h和1 d呈负相关,说明在强冷应激时,绵羊机体免疫机能的调节及抗炎症反应等受到了抑制。冷应激后十二指肠、空肠和回肠的显微结构发生了相应变化,其中最明显的是肠绒毛变短且变粗,回肠内淋巴小结数量增多;对小肠免疫相关细胞而言,同一温度下各肠段中细胞数量呈趋势变化,上皮内淋巴细胞和杯状细胞的数量在十二指肠、空肠和回肠中呈上升趋势,而肥大细胞数量呈下降趋势;冷应激后淋巴细胞数量较常温有所减少,杯状细胞和肥大细胞数量较常温下都有所增加,说明在强冷应激下机体通过激素的释放努力适应环境变化的同时,也会使小肠免疫功能下降。

In order to investigate the effect of strong cold stimulation on serum IgG and cortisol content in Altay lambs,and the adaptation characteristics of intestinal mucosal immune barriers,the Altay lambs were cold-stimulated for 0,6 h,1,4,12 and 24 d from-30℃to-35℃.The content of IgG and cortisol in the serum were detected by enzyme-linked immunoabsorbent assay(ELISA).Paraffin section and HE staining was applied to ovserve the structure of the small intestine.The special positive cells in the small intestine were identified by a modified toluidine blue staining method.The IgG concentration after cold stress was lower than that of room temperature(P<0.01),while the cortisol concentration was higher than that of room temperature,with a significant difference at 6 h and(P<0.05),24 d(P<0.01);The content of IgG and cortisol showed a strong positive correlation at 4,12 and 24 d,and a negative correlation at 6 h and 1 d.The results showed that under cold stress,sheep immune function regulation and anti-inflammatory response were inhibited.The microstructure of the duodenum,jejunum,and ileum after cold stress displayed the changes,with the most obvious being the shortening and thickening of the intestinal villi,and the increased number of lymphoid nodules in the ileum;under the same temperature,the of small intestine-immune related cells showed a trend,of wich the number of lymph cells and goblet cells increased in the duodenum,jejunum,and ileum,while the number of mast cells showed a decreasing;after cold stress,the number of lymphocytes decreased compared with normal temperature,and the number of goblet cells and mast cells was slightly increased.This results indicated that the lambs tried to adapt the environmental changes through hormone release under strong cold stress,and it will also make the intestinal immune function decreased.