Objective To investigate the neuroprotective effect of sophocarpine against transient focal cerebral ischemia via down-regulation of the acid-sensing ion channel 1(ASICl) in rats.Methods Twenty-five SD rats were randomly allocated into sham operation,cerebral ischemia/reperfusion,and 5,10,and 20 mg/kg sophocarpine pretreatment groups (n=5 in each group).A rat focal ischemia model was induced by the intraluminal suture method.Five,10 and 20 mg/kg sophocarpine were injected intraperitoneally for pretreatrnent.2,3,5-triphenyltetrazolium chloride staining was used to detect cerebral infarct volume.TUNEL staining was used to detect apoptosis.Immunohistochemistry and Western blot were used to detect the expression of ASIC1 and ASIC2.Results The infarct volume after ischemia-reperfusion was(181.21±9.21)mm3,while the 5,10,and 20 mg/kg sophocarpine pretreatment groups were(150.12±6.19),(52.31±4.20),and(32.18±3.82)mm3,respectively;the neurological function scores in the cerebral ischemia/reperfusion group was(3.62±0.36),while the 5,10,and 20 mg/kg sophocarpine pretreatment grows were(3.15±0.36),(1.92±0.18),and(1.85±0.21),respectively;The surviving neurons only accounted for(31.2±2.8)% of the total cell number in the cerebral ischemia-reperfusion group,while they accounted for(51.2±3.7)%,(76.5±2.1)%,and(77.1±4.1)% in the 5,10,and 20 mg/kg sophocarpine pretreatnmat groups.Compared with the cerebral ischemia/reperfusion group,the cerebral infarct volume was decreased significantly in the sophocarpine pretreatrnent groups(all P<0.01),the neurological function scores were decreased significantly(all P<0.01),and the number of apoptotic cells was decreased significantly (all P<0.01).Immunohistochemistry showed that the number of ASIC-1 positive cells in the sham operation,cerebral ischemia-reperfusion,and 5,10,and 20 mg/kg sophocarpine pretreatment groups were(162.5±8.3),(165.1±5.3),(138.3±7.2),(82.1±6.3),and(69.2±5.5)/mm respectively;Western blot showed that the ASIC1 protein expression was decreased sigaificantly in the 10 and 20 mg/ky sophocarpine pretreatment groups (P<0.01),while there WaS no significant difference in the ASIC2 protein expression.Condusions Sophocarpine may play a neuroprotective role for cerebral ischemia-reperfusion injury in rats via down-regulating the expression of ASIC1 protein.%目的 探讨槐果碱对酸敏感离子通道(acid-sensing ion channel,ASIC)的影响及其在缺血性脑损伤大鼠中的神经保护作用.方法 25只SD大鼠随机分为假手术组、脑缺血再灌注组以及槐果碱5、10和20 mg/kg预处理组,每组5只.采用线栓法建立局灶性大鼠缺血模型,5、10和20 mg/kg槐果碱腹腔注射预处理.2,3,5-氯化三苯基四氮唑染色法检测脑梗死体积,TUNEL染色法检测细胞凋亡,免疫组织化学法和Western印迹法检测ASICI和ASIC2表达.结果 脑缺血再灌注组脑梗死体积为(181.21±9.21)mm3,而5、10和20 mg/kg槐果碱预处理组分别为(150.12±6.19)、(52.31±4.20)和(32.18±3.82)mm3;脑缺血再灌注组神经功能评分为(3.62±0.36)分,而5、10和20 mg/kg槐果碱预处理组分别为(3.15±0.36)、(1.92±0.18)和(1.85±0.21)分;脑缺血再灌注组存活神经细胞仅占总细胞数(31.2±2.8)%,而5、10和20 mg/kg槐果碱预处理组分别为(51.2±3.7)%、(76.5±2.1)%和(77.1±4.1)%.与脑缺血再灌注组比较,槐果碱预处理组脑梗死体积显著缩小(P均<0.01),神经功能评分显著降低(P均<0.01),凋亡细胞数量显著减少(P均<0.01).免疫组化显示,假手术组、脑缺血再灌注组以及5、10和20mg/kg槐果碱预处理组ASICI阳性细胞数量分别为(162.5 ±8.3)、(165.1±5.3)、(138.3±7.2)、(82.1±6.3)和(69.2±5.5)个/mm2,10和20 mg/kg槐果碱预处理组ASICI显著减少(P均<0.01);Western印迹显示,假手术组、脑缺血再灌注组以及5、10和20 mg/kg槐果碱预处理组ASICI表达分别为0.58±0.08、0.61±0.10、0.42±0.07、0.12±0.03和0.19±0.02,10和20 mg/kg槐果碱预处理组显著下调(P均<0.01);ASIC2表达分别为0.51±0.06、0.58±0.11、0.49±0.05、0.55±0.03和0.51±0.11,各组之间无显著差异.结论 槐果碱可能通过下调ASICI表达对脑缺血再灌注大鼠起着神经保护作用.
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