蛛网膜下腔出血对M4型瞬时受体电位通道活性的影响

Effect of subarachnoid hemorrhage on transient receptor potential melastatin 4 channel activity

目的：研究自发性蛛网膜下腔出血（SAH）对M4型瞬时受体电位通道（TRPM4）活性的作用。方法取实验清洁级SD大鼠17只，按照随机数字表法完全随机分为SAH组（10只）和假手术组（7只）。SAH建模后第5天获取脑动脉并用酶促消化法分离脑动脉平滑肌细胞，运用蛋白印迹法检测TRPM4表达及转位率，运用膜片钳技术研究脑动脉平滑肌细胞TRPM4单通道最大电流强度。结果两组大鼠脑动脉平滑肌细胞中均可见荧光染色的TRPM4。假手术组和SAH组总蛋白中TRPM4相对量分别为（24±3）％和（32±4）％，组间差异有统计学意义（t ＝4.47，P ＜0.01）。假手术组和SAH组TRPM4的转位率分别为（44.0±1．9）％和（60.1±2．3）％，且SAH组高于假手术组（χ2＝4.48，P ＜0.05）。钳制电压为－100、－80、－60和－40 mV 时，假手术组TRPM4单通道最大电流强度均大于SAH组，组间差异均有统计学意义[（－1.90±0.10）mV比（－2.23±0.08）mV、（－1.68±0.12）mV比（－1.99±0.12）mV、（－0.89±0.09）mV 比（－1.24±0.09）mV、（－0.69±0.12）mV比（－0.92±0.11）mV，均P ＜0.01]；钳制电压为－20、0、20、40、60、80和100 mV时，两组TRPM4单通道最大电流强度差异均无统计学意义（均P ＞0.05）。结论 SAH 对TRPM4的活性具有诱导作用。

Objective To study the effect of spontaneous subarachnoid hemorrhage （SAH）on transient receptor potential melastatin 4 （TRPM4）channel activity. Methods Seventeen SD rats of clean grade were selected. They were randomly divided into either a SAH （n = 10）or a sham operation group （n = 7） according to the random number table. At day 5 after SAH modeling,the cerebral arteries were harvested and the cerebral arterial smooth muscle cells were isolated using enzymatic digestion method. Western blot was used to detect TRPM4 expression and translocation rate. Patch-clamp techniques were used to study the maximum current intensity of the TRPM4 single channel in cerebral arterial smooth muscle cells. Results The fluorescent-stained TRPM4 were observed in cerebral arterial smooth muscle cells in the 2 groups of rats. The relative quantities of TRPM4 in the total protein of the sham operation group and the SAH group were 24 ± 3% and 32 ± 4% respectively. There was significant difference between the 2 groups （t = 4. 47,P 0. 05）. Conclusion SAH has the induced effect for TRPM4 activity.