中文摘要：

目的研究大鼠心肌挫伤（myocardial contusion,MC）后细胞结蛋白（desmin）的破坏与钙超载情况,评价心肌挫伤后结蛋白破坏与钙超载的关系。方法 110只SD大鼠按随机数字表法分为标准对照组（S组,n=10）、单纯致伤组（T组,n=50）和致伤＋地尔硫卓组（D组,n=50）,BIM-Ⅲ生物撞击机建立胸部撞击致心肌挫伤模型,致伤后D组腹腔注射盐酸地尔硫卓（0.5 mg/kg）,分别于伤前,伤后2、4、8、24、48 h检测心肌细胞Ca2＋浓度,免疫组化法及Western blot检测心肌细胞结蛋白变化情况,RT-PCR检测结蛋白mRNA表达变化情况。结果①T组伤后2 h心肌细胞Ca2＋浓度较S组明显增高[（110.4±17.6）vs（74.0±9.3）,P〈0.01],伤后4 h达最高值（141.1±17.8）后逐渐下降,48 h恢复至伤前水平（78.6±10.3）;②MC后早期即出现严重的结蛋白破坏,T组伤后8 h结蛋白表达量降至最低[与S组比较,（0.11±0.11）vs（1.23±0.27）,P〈0.01],24 h开始部分恢复,伤后48 h结蛋白表达增高且出现排列紊乱和无规则聚集的现象;③与T组比较,D组显著降低了伤后4、8 h细胞内Ca2＋浓度[（84.6±9.7）、（89.3±11.8）],结蛋白表达量在伤后2、4 h两组相较无明显差异,但在伤后8 h,D组（0.55±0.18）高于T组（P〈0.05）;④T、D组结蛋白mRNA伤后表达增高,24 h达峰值,D组24 h后表达低于T组。结论 MC后早期结蛋白的破坏以细胞的机械损伤为主,随着细胞内Ca2＋浓度增高,其介导的心肌结蛋白降解增加。通过伤后应用钙通道阻滞剂降低Ca2＋浓度可有效减缓解结蛋白的降解破坏。

英文摘要：

Objective To study the correlation between desmin degradation and calcium overload in rats with myocardial contusion（MC）.Methods One-hundred-and-ten SD rats were randomly divided into a trauma（T） group（n=50）,a trauma ＋ diltiazem（D） group（n=50）,and a control（S） group（n=10）.The MC models were established by chest impact with BIM-III Bio-impactor.The animals in the D group were given diltiazem hydrochloride（0.5 mg/kg） through intraperitoneal injection after trauma.The Ca2＋ concentration,protein expression of desmin,and mRNA expression of desmin in myocardial cells were measured by confocal laser scanning microscopy,immunohistochemistry and Western blotting,and RT-PCR,respectively,before and after（2,4,8,24,and 48 h） trauma.Results Compared with that in the S group,the Ca2＋ concentration in myocardial cells in the T group increased significantly 2 h after trauma（110.4±17.6 vs 74.0±9.3,P0.01）,reached the peak 4 h after trauma（141.1±17.8）,and then decreased gradually to the level before trauma 48 h after trauma（78.6±10.3）.Compared with that in the S group,the protein expression of desmin in the T group decreased to the lowest level 8 h after trauma（0.11±0.11 vs 1.23±0.27,P0.01）,began to increase 24 h after trauma（1.06±0.33）,and was higher than the level before trauma 48 h after trauma（1.82±0.41）.Irregular aggregation of desmin was found in the T group at 48 h after trauma.Compared with the T group,the D group had a significantly lower Ca2＋ concentration in 4 and 8 h after trauma（84.6±9.7,89.3±11.8）.The protein expression of desmin showed no significant difference between the T group and D group in 2 and 4 h after trauma,but was higher in the D group than in the T group 8 h after trauma（0.55±0.18 vs 0.11±0.11,P0.05）.Compared with that of the S group（0.62±0.23）,the mRNA expression of desmin in the D group and T group increased after trauma and reached the peak at 24 h after trauma（1.24±0.30 and 1.63±0.31）.The mRNA expression