Carter E A, Hatz R A, Yarmush M L, Tompkins R G
Pediatric Gastrointestinal and Nutritional Laboratory, Massachusetts General Hospital, Boston.
Gastroenterology. 1990 Jun;98(6):1445-51. doi: 10.1016/0016-5085(90)91074-g.
Small intestinal mucosal weight and nutrient absorption are significantly diminished early after cutaneous thermal injuries. Because these intestinal properties are highly dependent on rates of nucleic acid and protein synthesis, in vivo incorporation of thymidine, uridine, and leucine into small intestinal deoxyribonucleic acid, ribonucleic acid, and proteins were measured. Deoxyribonucleic acid synthesis was markedly decreased with the lowest thymidine incorporation in the jejunum (p less than 0.01); these findings were confirmed by autoradiographic identification of radiolabeled nuclei in the intestinal crypts. Protein synthesis was decreased by 6 h postinjury (p less than 0.01) but had returned to normal by 48 h. Consistent with a decreased rate of protein synthesis, ribonucleic acid synthesis was also decreased 18 h postinjury (p less than 0.01). These decreased deoxyribonucleic acid, ribonucleic acid, and protein synthesis rates are not likely a result of ischemia because in other studies of this injury model, intestinal blood flow was not significantly changed by the burn injury. Potentially, factors initiating the acute inflammatory reaction may directly inhibit nucleic acid and protein synthesis and lead to alterations in nutrient absorption and intestinal barrier function after injury.
皮肤热损伤后早期，小肠黏膜重量和营养物质吸收显著降低。由于这些肠道特性高度依赖核酸和蛋白质合成速率，因此测定了体内胸腺嘧啶核苷、尿苷和亮氨酸掺入小肠脱氧核糖核酸、核糖核酸和蛋白质的情况。脱氧核糖核酸合成显著减少，空肠中胸腺嘧啶核苷掺入量最低（p<0.01）；通过放射自显影鉴定肠隐窝中的放射性标记细胞核证实了这些发现。损伤后6小时蛋白质合成减少（p<0.01），但在48小时时已恢复正常。与蛋白质合成速率降低一致，损伤后18小时核糖核酸合成也减少（p<0.01）。这些脱氧核糖核酸、核糖核酸和蛋白质合成速率的降低不太可能是缺血所致，因为在该损伤模型的其他研究中，烧伤并未使肠血流量发生显著变化。引发急性炎症反应的因素可能直接抑制核酸和蛋白质合成，并导致损伤后营养物质吸收和肠道屏障功能改变。
