小鼠肠道组织结构在低温环境下的适应性调整

对长期(3个月)处于低温条件下的小鼠各肠道组织结构的适应性变化进行了比较研究。低温驯化后小鼠的体重(P0.05)、消化道总长度(P0.05)、小肠长度(P0.01)和盲肠长度(P0.05)显著增加,而十二指肠肠腔隙截面积未发生显著变化,提示小鼠的肠腔隙体积在低温环境下明显增加。同时,低温驯化小鼠十二指肠的肠道和肠壁组织截面积均显著降低(P0.05),而其绒毛高则显著增加(P0.001),提示其黏膜层厚度增加,而黏膜下层结构趋于萎缩,表明小鼠肠道组织的形态结构为应对低温条件已经产生了适应性调整,即通过增加消化道的长度和营养物质的吸收面积来增加食物摄取量、食物吸收速率和吸收效率等,进而满足低温条件下小鼠能量需求的增加。相比之下,低温鼠的胃大小、盲肠重量、大肠长度与重量、直肠组织结构均未产生显著变化,暗示这些肠道结构对外界温度变化的敏感性相对较低。研究结果表明,小型哺乳类主要通过增大消化道长度和吸收面积来提高其消化效率,通过改变消化道的形态和结构来提高消化和吸收效率,以便更好地去适应环境温度变化而导致的能量需求变化。

Morphological and histological plasticity in digestive tracts of cold-acclimated Kunming laboratory mice

The present study investigated adaptive changes in the intestinal tissue structure of mice subject to long-term cold exposure. The body weight (P < 0.05), total digestive-tract length (P < 0.05) and small intestine length (P < 0.01) of the mice were increased by cold exposure, whereas the lumen area of the duodenum remained unchanged, indicating that the digestive volume and food capacity of mice are increased in cold environment. In addition, the section and wall areas of the duodenum were significantly reduced by cold exposure (P < 0.01), whereas the villus height was increased, indicating the increased thickness of mucosal layer but the decreased thickness of submucous layer in mice under long-term cold exposure. These results demonstrate that gastrointestinal tracts of small mammals are capable of adaptive changes to cope with cold environments by increasing digestive tract length and absorption area for higher absorption rate and efficiency. In contrast, the stomach size, cecum length, caecum weight, and rectum histology were not attested significantly, indicating that the morphology of these structures is relatively stable. Collectively, these results demonstrate that mice are able to adapt to changes in environment temperature and energy demand via phenotypic plasticity in digestive morphology and histology.