摘要目的 观察瞬时受体通道C(TRPC)亚型(TRPC1、3、4、5、6、7)在心肌肥厚大鼠心肌中的表达.方法 成年雄性SD大鼠30只,体质量200～240 g.按体质量采用随机数字表法将大鼠分为模型组(20只)和对照组(l0只).模型组通过胸主动脉缩窄术复制大鼠心肌肥厚模型,对照组不结扎胸主动脉,其他手术过程与模型组相同.术后10周,超声心动图检查大鼠心功改变;取大鼠心脏,称重、计算心肌肥厚指数;10％甲醛固定心肌,切片、HE染色,光镜下观察心肌组织的形态学变化.应用实时定量PCR法测定心肌TRPC亚型(TRPC1、3、4、5、6、7)mRNA表达;应用蛋白质免疫印迹(Western blot)法测定心肌TRPC4、TRPC5的蛋白表达,并比较心肌肥厚指数与TRPC4、TRPC5蛋白表达的关系.结果 超声心动图显示,模型组较对照组室间隔厚度、后壁的厚度明显增加[mm:(2.64±0.31)比(1.89±0.15)、(2.30±0.14)比(1.60±0.09),t=9.19、8.57,P均＜0.05].与对照组比较,模型组心肌肥厚指数明显上升[(3.21±0.15)比(1.82±0.10)mg/g,t=17.02,P＜0.01].光镜下,模型组大鼠心肌细胞肥大,细胞核形态异常并明显增大,同时心肌间质纤维结缔组织增生.与对照组比较,模型组大鼠TRPC4、TRPC5 mRNA表达明显增高(1.51±0.48比1.22±0.25、1.65±0.35比1.27±0.87,t=3.55、4.65,P均＜0.05).与对照组比较,模型组TRPC4、TRPC5蛋白表达明显增高(1.45±0.68比1.00±0.54、1.58±0.93比1.00±0.65,t=5.51、7.10,P均＜0.05),心肌肥厚指数与TRPC4、TRPC5蛋白表达相关(r=0.728、0.681,P均＜0.05).结论 TRPC4、TRPC5 mRNA和蛋白表达在心肌肥厚大鼠心肌中明显升高.

abstractsObjective To study the expression of transient receptor potential channel (TRPC) isoforms (TRPC1,3,4,5,6,7) inrats with cardiac hypertrophy.Methods Thirty adult male SD rats,weighing 200-240 g were divided into surgical group (model group,20 rats) and sham group (control group,10 rats) by random number table according to body weight.Aortic coarctation surgery was performed to establish a rat model of myocardial hypertrophy and the control group did not ligate thoracic aorta,but the same surgical procedure with the model group was performed.After 10 weeks,echocardiography was used to check changes of cardiac function; cardiac tissues of rats were weighed and cardiac hypertrophy index was calculated.Cardiac HE staining was used for observation of myocardial tissue morphological changes.Quantitative RT-PCR method was used for measuring the mRNA expression of TPRC isoforms (TRPC1,3,4,5,6,7).Western blotting assay was applied to detect the protein expression of TRPC4 and TPRC5 in hypertrophic cardiac tissue of rats.The relationship between cardiac hypertrophy exponential and TRPC4,TRPC5 protein expression was studied.Results Echocardiography showed that the septal thickness and posterior wall thickness in model group increased significantly compared with those of the control group [mm:(2.64 ± 0.31) vs.(1.89 ± 0.15),(2.30 ± 0.14) vs.(1.60 ± 0.09),t =9.19,8.57,all P ＜ 0.05].Compared with the control group,cardiac hypertrophy index was significantly increased in model group [(3.21 ± 0.15)vs.(1.82 ± 0.10)mg/g,t =17.02,P ＜ 0.01].HE staining of myocardium showed that cardiomyocyte hypertrophy,abnormal nuclear morphology and significantly enlarged nuclear,and hyperplasia of myocardial interstitial fibrous connective tissue could be seen in model group.The mRNA expression of TRPC4 and TRPC5 was significantly increased in the model group as compared to those of the control group (1.51 ± 0.48 vs.1.22 ± 0.25,1.65 ± 0.35 vs.1.27-± 0.87,t =3.55,4.65,all P ＜ 0.05).The protein expression of TRPC4 and TRPC5 was significantly increased in the model group as compared to those of the control group (1.00 ± 0.54 vs.1.45 ± 0.68,1.00 ± 0.65 vs.1.58 ±0.93,t =5.51,7.10,all P ＜ 0.05).The protein expression of TRPC4 and TPRC5 were associated with cardiac hypertrophy index (r =0.728,0.681,all P ＜ 0.05).Conclusion Expression of TRPC4 and TRPC5 is increased in rats with cardiac hypertrophy.