早期肠道喂养对烧伤大鼠肠道一氧化氮合酶的影响

Effects of early enteral feeding on nitric oxide synthase activity in small intestine in burned rat

目的阐明烧伤大鼠经早期肠道喂养后肠组织中一氧化氮合酶(NOS)的变化规律及其与肠粘膜血流量(IMBF)的关系。方法采用30％TBSAⅢ度烧伤大鼠模型,分为正常对照(C)组,单纯烧伤(B)组和早期喂养(EF)组,分别检测伤前及伤后0,3,6,12,24,48小时肠组织中 NOS 活性,包括原生型 NOS(cNOS)和诱导型 NOS(iNOS),并测定肠粘膜血流量。结果烧伤后各组 cNOS 和 IMBF 呈下降趋势,二者呈显著正相关(r=0.97,P<0.01),而 NOS 总活性和 iNOS 活性都呈上升趋势,IMBF 与 iN-OS 和总 NOS 相关不显著。烧伤后 EF 组 cNOS 和 IMBF 明显高于 B 组,iNOS 则低于 B 组,NOS 总活力两组无显著差异。结论①两型 NOS 中 cNOS 与 IMBF 的关系更加密切。②早期肠道喂养改善烧伤后肠道缺血状况,可能与食物对肠壁神经的刺激从而提高 cNOS 活性有关。

Objective Our previous studies have proved that early enteral feeding could improve intestine blood flow after burn injury.But the mechanism was far from being clarified.This study was attempted to explore the effects of early enteral feeding on nitric oxide synthase (NOS) activity in burned rat small intestine and the relationship between the intestine mucosa blood flow (IMBF) and the activity of NOS.Methods The rats were randomly divided into three groups:burned control (B), burned and early enteral feeding(EF),and normal control(C).The activity of NOS including constitute NOS(cNOS) and inducible NOS(iNOS),and the IMBF were determined at postburn 0,3,6,12,24,48 hours.Results It was found that cNOS activity and IMBF were decreased markedly postburn,and there was positive correlation between eNOS and IMBF(r=0.97,P<0.01).But the activity of iNOS, total NOS were increased significantly postburn,they had no correlation to the IMBF.In EF group cNOS activity and the IMBF were significantly higher,the iNOS was obviously lower than that of B group and there was no significant difference of total activity of NOS between two groups.Conclusion Our results suggested that NOS which is catalyzed from cNOS may play main role in adjusting IMBF.By using early enteral feeding the activity of cNOS is increased and the ischemie state in small intestine is improved after burn injury.