12-脂加氧酶对实验性自身免疫性心肌炎小鼠心肌细胞凋亡的影响

Expression and association of 12-LO with apoptosis in mice with experimental autoimmune myocarditis

目的探讨实验性自身免疫性心肌炎（EAM）小鼠心肌内12-脂加氧酶（12-LO）的表达，外周血NO水平及其与细胞凋亡的关系。方法4～5周龄雄性BALB／C小鼠随机分成免疫性心肌炎组（AM组）和正常对照组（C组）各24只。AM组在实验的第1、7天在腹股沟皮下注射含猪心肌球蛋白100μg的混合液0．2ml，C组于同时间同部位注射等量混合液（不含猪心肌球蛋白）。实验的第14、21、30天随机抽取各组小鼠8只取血后处死，留取心脏标本。RT-PCR法测定小鼠心肌细胞12．LOmRNA、iNOSmRNA，硝酸还原酶法检测小鼠血清NO水平，TUNEL法检测细胞凋亡指数（AI）。结果AM组12-LOmRNA、iNOSmRNA、NO及AI均在第21天（分别为1．53±0．27；92．74±3．99；76．44±3．01；24．97±1．54）明显高于第14天（分别为0．68±0．28；82．99±2．64；57．51±2．17；13．20±2．54）和第30天（分别为1．05±0．10；87．40±3．32；64．77±3．92；14．95±2．15），P均〈0．05；与C组相比，各时间点上述指标均明显升高（均P〈0．05）；AM组12-LOmRNA与NO、AI呈显著正相关（r=0．882；0．877；P〈0．05）。结论自身免疫性心肌炎小鼠心肌细胞12-L0表达增加，促进心肌细胞凋亡及病情进展；12-LO可能通过氧化应激影响NO来参与AM的发病过程。

Objective To examine the myocardial expressions of 12-1ipoxygenase （12-LO）, NO levels in the peripheral blood in mice with experimental autoimmune myocarditis, and analyze the relationship between their expressions and apop- tosis. Methods A total of five-week-old male BALB/C mice were randomly divided into two groups： control group （C group 24） and autoimmune myocarditis group（ AM group 24）. AM group were immunized with porcine heart myosin（ 100 ~g） in an equal content of CFA in a total volume of 0.2 ml and C group were injected with PBS in an equal content of CFA in a total volume of 0.2 ml at the lth day and 7th day. Eight mice of each group were sacrificed in 14th,21th and 30th day. Expression of 12-LO and iNOS mRNA was determined by RT-PCR. Serum NO levels was measured by Nitrate reductase. The histological and ultrastructure changes were observed under light microscope and electron microscope. Re- suits The expression of 12-LO mRNA, iNOS mRNA, NO and apoptotic index （AI） were up-regulated at the 14th day （0.68 ± 0.28 ; 82.99 ±2.64 ;57.51 ± 2.17 ; 13.20 ±2.54 ） and reached peak at the 21 th day （ 1.53± 0.27 ; 92.74 ± 3.99 ; 76.44 ±3.01 ;24.97 ± 1.54）, then decreased at the 30th day （ 1.05 ± 0.10 ; 87.40 ± 3.32 ; 64.77 ± 3.92 ; 14.95 ± 2.15）. Compared with C group,These indicators were significantly higher in AM group （P 〈 0.05 ）. And 12-LO mRNA expression in the AM group was significantly correlated with NO and apoptotic index（ r = 0.882 ;0.877 ;P 〈 0.05 ）. Con- clusion The expression of NO and 12-LO are found in mice with autoimmune myocarditis, and they are positively associ- ated. 12-LO involved in the pathogenesis of AM, may be affected by oxidative stress via NO.