新生鼠坏死性小肠结肠炎肠上皮细胞Bax表达与细胞凋亡的初步研究

目的探讨新生鼠坏死性小肠结肠炎（necrotizingenterocolitis，NEC）时肠上皮细胞Bax表达与凋亡相关性。方法出生当日48只清洁级SD新生鼠采用奇、偶数方法随机分为对照组和NEC模型组，每组24只。对照组由母鼠喂养。模型组与母鼠分开，通过代乳品人工喂养＋缺氧一复氧一冷刺激建立新生鼠NEC动物模型。分别于实验开始后24h、48h、72h留取大鼠回盲部近段回肠组织行免疫组织化学法检查肠上皮细胞Bax表达，原位末端标记法检测肠上皮细胞凋亡率。结果与对照组[（666．55±15．77）IOD；（4．73±0．04）％]相比，NEC模型组新生鼠肠上皮细胞Bax表达和细胞凋亡率在实验开始后24h开始升高[（1005．06±11．96）IOD；（15．04±0．24）％]（P〈0．01），72h后达到高峰[（3340．66±68．72）IOD；（35．65±0．61）％]（P〈0．01）。NEC模型组新生鼠肠上皮细胞凋亡率与肠上皮细胞Bax表达量呈正相关（r=0．94，P〈0．01）。结论新生鼠NEC肠上皮细胞凋亡与Bax表达有明确相关性。新生鼠NEC肠上皮细胞可能通过高表达Bax导致肠上皮细胞凋亡。

Expression of Bax and apoptosis in enterocytes of neonatal rats with necrotizing enterocolitis

Objective To investigate the correlation of Bax and apoptosis in enterocytes of neonatal rats with necrotizing enterocolitis （NEC）. Methods Forty-eight neonatal rats （ 1 day） were randomly divided into control group（ n = 24 ） and NEC model group（ n = 24 ） by use of odd and even. The rats in control group were maternal breast-fed. The rats in NEC model group were separated from their mothers. To be given for- mula feeding, cold exposure after hypoxic-reoxygenation treatment. The intestinal tissue located at the bounda- ry of ileum and caecum of two groups were gained on the 24 h,48 h and 72 h with which that all rats were sacrificed by cutting neck. Section of intestinal tissue were stained with immunohistochemistry to detect the expression of Bax and were stained with TdT mediated dUTP nick end labeling（TUNEL） to evaluate the ap- optosis in each group. Results The integrate optical density （IOD） value of expression of Bax in the NEC model group began to increase on the 24 h [ （ 1 005.06 ± 11.96 ） IOD ] and reached the summit on the 72 h （3 340. 66 ±68. 72） ] compared with the control groupE （666. 55 ± 15.77）IOD]. A few of TUNEL positive cells began to increase with time dependence. A lot of TUNEL positive cells could be found in NEC model group on the 24 h [ （ 15.04 ± 0. 24 ） % ], and the apoptotic index reached the peak on the 72 h [ （ 35.65 ± 0. 61 ） % ] compared with the control group[ （4. 73±0. 04） % ,P 〈0.01 ]. There was a significantly positive correlation between the cell apoptosis and the ratio change of Bax in NEC model group（ r = 0.94, P 〈 0. 01 ）. Conclusion There is a significantly positive correlation between the cell apoptosis and the ratio change of Bax in enterocytes of neonatal rats with NEC. The cell apoptosis in enterocytes of neonatal rats with NEC maybe be induced by Bax.