论文部分内容阅读
目的研究选择性头部降温对缺血性脑损伤胎羊纹状体神经元凋亡和星形胶质细胞增殖的影响。方法胎羊于妊娠117~124d时通过双侧颈动脉阻塞30min造成双侧脑缺血损伤,损伤后将胎羊随机分为:损伤组(n=10)、2h低温组(损伤后2h开始亚低温治疗,n=7)和6h低温组(损伤后6h开始亚低温治疗,n=8),另设正常对照组(n=5)。通过冷循环水进行选择性头部降温,取脑组织用免疫组化法检测胎羊纹状体caspase-3(半胱天冬氨酸酶-3),GFAP(胶质纤维酸性蛋白)和PCNA(增殖细胞核抗原)的表达。结果①纹状体神经元凋亡:正常对照组中,caspase-3表达极少(11.00±13.77),损伤组caspase-3免疫阳性细胞为177.70±48.69,明显增加(P=0.000),损伤后2h治疗组(54.14±39.44,P=0.000)和损伤后6h治疗组(122.43±52.36,P=0.017)均能减少caspase-3免疫阳性细胞。②纹状体星形胶质细胞增殖:与正常对照组(163.40±21.98)相比,缺血性脑损伤组的GFAP免疫阳性细胞明显增多(433.25±66.69,P=0.000),损伤后2h开始亚低温治疗(219.50±35.31,P=0.000)和损伤后6h开始亚低温治疗(272.50±86.20,P=0.000)均能减少GFAP免疫阳性细胞。③纹状体PCNA阳性细胞的表达:在正常对照组中,PCNA免疫阳性细胞较少,为153.40±12.46,缺血性脑损伤组的PCNA免疫阳性细胞明显增多(353.70±45.60,P=0.000),损伤后2h开始亚低温治疗(187.14±26.26,P=0.000)和损伤后6h开始亚低温治疗(230.25±67.46,P=0.000)均能减少PCNA免疫阳性细胞。结论亚低温可以抑制纹状体神经元的凋亡和星形胶质细胞的增殖,该作用可能为选择性头部降温的脑保护作用机制之一。
Objective To investigate the effects of selective head cooling on the apoptosis and astrocyte proliferation in fetal rat striatum after ischemic brain injury. Methods The fetuses were divided into two groups randomly: injured group (n = 10), hypothermia group 2h (subgroup 2h after injury) (N = 7) and 6h hypothermia group (hypothermia treatment started 6h after injury, n = 8), and another normal control group (n = 5). Selective head cooling was performed by cold water circulation, and the brain tissue was removed for immunohistochemistry to detect the expression of caspase-3, GFAP (glial fibrillary acidic protein) and PCNA (Proliferating cell nuclear antigen) expression. Results ① The apoptosis of striatum neurons: In the normal control group, the expression of caspase-3 was extremely low (11.00 ± 13.77), the number of caspase-3 positive cells in the injury group was 177.70 ± 48.69 (P = 0.000) The 2h treatment group (54.14 ± 39.44, P = 0.000) and the 6h treatment group (122.43 ± 52.36, P = 0.017) all reduced the caspase-3 immunopositive cells. (2) Striatal astrocyte proliferation: Compared with the normal control group (163.40 ± 21.98), the number of GFAP immunopositive cells in the ischemic brain injury group increased significantly (433.25 ± 66.69, P = 0.000) Mild hypothermia treatment (219.50 ± 35.31, P = 0.000) and hypothermia treatment at 6h after injury (272.50 ± 86.20, P = 0.000) decreased GFAP immunoreactive cells. (3) The expression of PCNA positive cells in the striatum: The number of PCNA positive cells in the normal control group was 153.40 ± 12.46, and the number of PCNA immunopositive cells in the ischemic brain injury group was significantly increased (353.70 ± 45.60, P = 0.000) , Mild hypothermia (187.14 ± 26.26, P = 0.000) at 2h after injury and mild hypothermia at 6h after injury (230.25 ± 67.46, P = 0.000) all reduced PCNA immunopositive cells. Conclusion Mild hypothermia can inhibit the apoptosis of striatal neurons and the proliferation of astrocytes, which may be one of the protective mechanisms of selective head cooling.