4-苯基丁酸抑制内质网应激对大鼠皮瓣缺血再灌注损伤的影响

Effects of 4-phenylbutyrate on the ischemia-reperfusion injury of rat skin flaps by inhibiting endoplasmic reticulum stress

目的观察4-苯基丁酸（4-PBA）抑制内质网应激对大鼠皮瓣缺血再灌注损伤的影响。方法选择Wistar大鼠75只，建立大鼠腹部皮瓣缺血再灌注损伤模型，随机分为对照组、4-PBA组、生理盐水组（NC组）。对照组大鼠皮瓣形成后及4-PBA组、NC组皮瓣缺血再灌注后0、1、6、12、24h，分别于皮瓣边缘取全厚皮瓣组织，行病理形态学观察；应用原位末端脱氧核苷转移酶标记法（TUNEL）检测皮瓣组织细胞凋亡情况；RT-PCR法检测GRP78、CHOPmRNA表达水平；Western-blot及免疫荧光染色法分析GRP78、CHOP蛋白表达水平，并行相关性分析。结果组织学观察发现NC组在缺血再灌注损伤6h后组织肿胀程度、坏死细胞和炎性细胞数较4-PBA组明显增加。缺血再灌注损伤6和24h，4-PBA组与NC组相比TUNEL阳性细胞数分别减少19．4％和26．1％，差异有统计学意义（P〈0．05）。缺血再灌注损伤6、12、24h，4-PBA组较NC组CHOP、GRP78 mRNA表达水平及蛋白表达水平明显降低，差异有统计学意义（P〈0．05）。结论4-PBA通过抑制内质网应激介导的细胞凋亡机制，能减轻大鼠皮瓣缺血再灌注损伤后细胞凋亡，起到对皮瓣缺血再灌注后的保护作用。

Objective To observe the effects of 4-phenylbutyrate （4-PBA） on the ischemia- reperfusion injury of rat skin flaps by inhibiting endoplasmic reticulum stress. Methods Seventy-five Wistar rats were used to create the abdominal island skin flaps. They were then randomly divided into three groups： control group, 4-PBA group and saline group （NC group）. In NC and 4-PBA groups, a skin flap tissue sample was removed at the time the skin flap was created 0, 1, 6, 12 and24 hours following ischemia reperfusion. In the control group, a skin flap tissue sample was removed at the time the skin flap was created 0, 1, 6, 12 and 24 hours following the surgical procedure. Pathological observation, detection of apoptosis by TUNEL method, RT-PCR detection of the expression level of GRP78 and CHOP mRNA, Western-blot and immunofluorescence staining for expression level of GRP78 and CHOP proteins were carried out. The correlation was analyzed. Results Histology showed that the tissue swelling degree, necrotic cells and inflammatory cells in NC group was more severe than 4-PBA group following 6 hours of ischemia and reperfusion. The number of TUNEL positive ceils in 4-PBA group, compared with NC group, were reduced by 19.4% and 26.1%, respectively, following 6 and 24 hours of ischemia and reperfusion with significant difference （P〈0.05）. The levels of both mRNA and protein expression of GRP78 and CHOP were lower in 4-PBA group than NC group following 6, 12 and 24 hours of ischemia and reperfusion with significant difference （P〈0.05）. Conclusion 4-PBA reduces cell apoptosis in rat skin flaps following ischemia- reperfusion injury by inhibiting endoplasmic reticulum stress-mediated apoptosis mechanism. It plays an important role in protecting rat skin flaps against ischemia reperfusion injury and apoptosis.