目的:探讨动脉性和静脉性蛛网膜下腔出血( SAH)对脑动脉平滑肌细胞电压依赖性钙通道( VDCCs)电流与动静脉血中氧合血红蛋白( OxyHb)浓度以及脑血流量的关系。方法取36只清洁级大鼠,在立体定向仪辅助下,采用鞍上池内注射自体动脉血或静脉血制作大鼠SAH模型。分为动脉性SAH(14只)、静脉性SAH组(13只)和假手术组(9只),并测定动脉血和静脉血OxyHb浓度。SAH模型建立后3 d,用膜片钳检测大鼠脑静息电位和VDCCs电流,用荧光微球法定量分析脑血流量(CBF)。结果(1)动脉性SAH大鼠OxyHb水平明显高于静脉性SAH,分别为(127±4)、(54±6)g/L,假手术组为(50±5)g/L,3组比较差异有统计学意义( P<0.01)。(2)动脉性SAH组VDCCs最大电流明显高于静脉性SAH组和假手术组,分别为(3.22±0.31)、(2.19±0.27)、(2 .1 8± 0.29)pA(P<0.01)。动脉性SAH组VDCCs电流由L-和R-型构成,而静脉性 SAH组电流仅由L-VDCCs构成。(3)动脉性SAH组脑血流量明显低于静脉性 SAH 组和假手术组,分别为(0.83±0.14)、(1.28±0.28)、(1.35±0.19)ml/(g·min)(P<0.01)。结论动脉性SAH对脑动脉平滑肌细胞VDCCs表达和功能的改变作用大于静脉性SAH,该差异可能与动静脉血中OxyHb等血管痉挛因子的浓度和成分差异有关。
Objective To investigate the effect of arterial and venous subarachnoid hemorrhage ( SAH)on voltage-dependent calcium channel( VDCC)currents of cerebral artery smooth muscle cells and the relationship between the concentration of oxyhemoglobin( OxyHb)in arterial and venous blood and cerebral blood flow. Methods Thirty-six clean grade rats were colleted. A rat SAH model was induced by injection of autologous arterial or venous blood in suprasellar cistern using assisted stereotaxic apparatus. The rats were divided into three groups:an arterial SAH( n=14 ),a venous SAH( n=13 ),and a sham operation( n=9 )group. The arterial and venous OxyHb concentrations were measured. Three days after SAH modeling,a patch clamp was used to detect the relative surface area of the cerebral artery smooth muscle cells,resting potential,and VDCC currents in rats. A fluorescent microsphere method was used to quantitatively analyze cerebral blood flow(CBF). Results (1)Arterial SAH OxyHb concentration (127 ± 4 g/L)was significantly higher than venous SAH OxyHb concentration(54 ± 6 g/L),and that of the sham operation group was 50 ± 5 g/L. The differences were statistically significant among the 3 groups( P<0. 01).(2)The maximum current of VDCC of the arterial SAH group(3. 22 ± 0. 31 pA)was significantly higher than that of the venous SAH group(2. 19 ± 0. 27 pA)and the sham operation group(2. 18 ± 0. 29 pA). The differences were statistically significant among the 3 groups( P<0. 01 ). The VDCC currents of the arterial SAH group were consisted of L- and R-currents,while the currents of the venous SAH group were only consisted of L-VDCC.(3)The cerebral blood flow of the arterial SAH group(0. 83 ± 0. 14 mL/[g·min])was significantly higher than that of the venous SAH group(1. 28 ± 0. 28 mL/[g·min])and the sham operation group(1. 35 ± 0. 19 mL/[g·min]). The differences were statistically significant(P<0. 01). Conclusions The changing effect of arterial SAH on the expression and function of the cerebral artery smooth muscle cells are greater than that of the venous SAH. This difference may be associated with the concentration and composition of vasospasm factors of OxyHb in arterial and venous blood.