p38丝裂原活化蛋白激酶抑制剂减少大鼠肝脏炎症细胞因子的表达

目的 观察p38丝裂原活化蛋白激酶(MAPK)抑制剂SB203580阻断p36 MAPK信号通路,减少脑死亡大鼠肝脏促炎细胞因子表达的作用.方法 雄性Wistar大鼠30只,体质量180～200 g,随机分3组,每组10只.脑死亡组:诱导大鼠及死亡;脑死亡+SB203580组:大鼠脑死亡诱导成功后,经阴茎背静脉注射SB203580(10 mg/kg);两组大鼠脑死亡诱导成功,行人工呼吸6 h后,若平均动脉压大于80 mm Hg(1 mm Hg=0.133 kPa),则为脑死亡供体,获取肝脏待检.对照组:正常大鼠麻醉后取肝脏待检.逆转录-聚合酶链反应检测肝脏肿瘤坏死因子(TNF)α和白细胞介素(IL)-1β的mRNA表达,Western blot检测肝脏TNF α和IL-1 β的蛋白质表达以及磷酸化p38 MAPK的表达.多个样本间比较行One-Way ANOVA分析,SNK法行两两样本间比较.结果 脑死亡组大鼠肝脏出现p38 MAPK磷酸化,磷酸化p38 MAPK的相对表达量比对照组明显增加(0.190±0.004比0.001±0.002),差异有统计学意义(q=172.53,P＜0.01);肝脏TNF α的mRNA和蛋白质表达量分别为0.670±0.012和0.240±0.003,较对照组(分别为0.130±0.013和0.001±0.002)明显增加(q值分别为123.99和243.09,P值均＜0.01);肝脏IL-1 β的mRNA和蛋白质表达量分别为0.560±0.009和0.190±0.003,较对照组(分别为0.160±0.010和0.001±0.002)明显增加(q值分别为135.35和192.23,P值均＜0.01).脑死亡SB203580组大鼠肝脏p38 MAPK磷酸化下降,磷酸化p38 MAPK的表达量(0.120±0.004)比脑死亡组明显下降(q=63.90,P＜0.05),但仍明显高于对照组(q=108.63,P＜0.01);肝脏TNF α的mRNA和蛋白质表达量分别为0.430±0.016和0.180±0.004,较脑死亡组明显下降(q值分别为55.11和61.03,P值均＜0.01),但仍高于对照组(q值分别为68.89和182.06,P值均＜0.01);肝脏IL-1β的mRNA和蛋白质表达量分别为0.270±0.009和0.140±0.004,较脑死亡组明显下降(q值分别为98.13和50.85,P值均＜0.01),但仍高于对照组(q值分别为37.22和141.38,P值均＜0.01).结论 SB203580能抑制p38 MAPK的磷酸化,阻断p38 MAPK信号通路,减少脑死亡大鼠肝脏促炎细胞因子表达,降低肝脏免疫原性.

p38 mitogen-activated protein kinase inhibitor suppresses the expression of pro-inflammatory cytokines in liver from brain dead rats

Objective To observe the suppressive effect on the expression of pro-inflammatory cytokines in liver from brain dead (BD) rats through inhibition of p38 mitogen-activated protein kinase (MAPK)signaling pathway by SB203580. Methods A total of 30 male Wistar rats weighing from 180 to 200 g were randomly divided into 3 experimental groups: (1) BD group (n = 10): brain death was induced in rats; (2)BD+SB203580 group (n = 10): brain death was successfully induced and SB203580 (10 mg/kg) was given through dorsal vein of penis. After brain death artificial ventilation was maintained for 6 hours and only those with mean arterial blood pressure more than 80 mm Hg (1 mm Hg = 0.133 kPa) were accepted as BD donors.(3) Control group (n = 10): living healthy rats. The expressions of TNF α and IL-1 β mRNA in liver tissues were analyzed by RT-PCR and the protein expressions of TNF α, IL-1 β and phosphorylated p38MAPK were detected by Western blot. Results The phosphorylated p38MAPK detected in the liver in BD group was significantly increased compared with the control group (q = 172.53, P ＜ 0.01), and the expressions of TNF α and IL- 1 β mRNA and proteins in liver were also significantly increased in BD group compared with the control group (q = 123.99, 135.35, 243.09 and 192.23, respectively, P ＜ 0.01). The phosphorylated p38MAPK was decreased in BD+SB203580 group and significantly decreased compared with the BD group (q = 63.90, P ＜ 0.05), but higher than that in control group (q = 108.63, P ＜0.01). The expressions of TNF α and IL- 1β mRNA and proteins in liver were significantly decreased in BD+SB203580 group compared with the BD group (q = 55.11, 98.13, 61.03 and 50.85, respectively, P ＜ 0.01), but higher than that in control group (q = 68.89, 37.22, 182.06 and 141.38, respectively, P ＜ 0.01). Conclusion SB203580 can suppress the expression of pro-inflammatory cytokines in the liver of brain dead rats through the inhibition of p38MAPK signaling pathway which may reduce the immunogenicity of donor livers.