重组人生长激素对烧伤大鼠肠粘膜结构及细胞凋亡的影响

目的　探讨重组人生长激素 (rhGH)的早期应用对严重烧伤大鼠小肠粘膜的保护作用。　方法　 30只成年雄性Wistar大鼠随机分为对照组、烧伤组和rhGH组 ,每组 10只。后两组造成2 5 %TBSAⅢ度烧伤创面 ,立即腹腔注射地塞米松 80mg/kg ,从伤后 2h开始分别给予等渗盐水和rhGH(1.33U·kg-1·d-1)。于伤后 30、96h ,观察回肠末端粘膜组织形态、肠上皮细胞超微结构和肠粘膜细胞增殖活性与凋亡率变化。　结果　烧伤组肠粘膜形态结构及上皮细胞损伤严重 ,rhGH组明显减轻 ,基本接近对照组 ;伤后 30h烧伤组和rhGH组肠粘膜细胞增殖指数 (proliferativeindex ,PI)均明显高于对照组 (P <0 .0 5～ 0 .0 1) ,但两组之间差异无显著性意义 ;伤后 96h ,rhGH组PI较烧伤组和对照组均明显升高 (P <0 .0 1)。烧伤组肠粘膜细胞凋亡率较对照组明显升高 (P <0 .0 1) ,rhGH组凋亡率较烧伤组 (P <0 .0 1)和对照组 (P <0 .0 5 )明显下降。　结论　rhGH能促进严重烧伤后肠粘膜细胞增殖 ,但作用缓慢 ;能抑制肠粘膜细胞凋亡 ,而且作用迅速、效果明显 ,并可能通过抑制作用减轻肠粘膜损伤 ,维护形态结构的基本正常。

The influence of recombinant human growth hormone on the apoptosis and intestinal mucosal structure in severely scalded rats

OBJECTIVE: To explore the influence of recombinant human growth hormone (rhGH) on the apoptosis and intestinal mucosal structure in severely scalded rats. METHODS: Thirty male Wistar rats were randomly divided into three groups, i.e. control, scalding and rhGH groups. The rats in scalding and rhGH groups were inflicted with 25% TBSA III degree scalding on the back and immediately followed by intraperitoneal injection of dexamethasone (80 mg/kg). The scalded rats were administered with normal saline and rhGH (1.33 IU.kg(-1).d(-1)) since 2 postburn hours (PBHs), respectively in the last two groups. The changes of the apoptosis rate, the intestinal mucosal proliferative index (PI) and epithelial ultrastructure and the intestinal mucosal pathomorphology of the distal end of ileal mucosal tissue were observed on 30 and 96 PBHs. RESULTS: The intestinal mucosa morphology and epithelia in scalding group were severely injured but were significantly ameliorated by rhGH to near those in control group. The PI in rhGH and scalding groups at 30 PBHs was evidently higher that that in control group (P < 0.05 - 0.01). But the PI exhibited no obvious difference between scalding and rhGH groups. While the PI in rhGH group at 96 PBHs was obviously higher than that in both scalding and control groups (P < 0.01). The intestinal mucosal epithelial apoptotic rate in scalding group was significantly higher than that in control group (P < 0.01), while that in rhGH group was evidently lower than that in scalding and control groups (P < 0.05 - 0.01). CONCLUSION: rhGH could promote postburn intestinal mucosa epithelial proliferation in slow - action manner and inhibit intestinal mucosal epithelial apoptosis with rapid and obvious effects. As a result, the intestinal mucosal epithelial injury could be ameliorated by rhGH by means of its inhibiting roles and the normal morphological structure of intestinal mucosa was maintained ad hoc.