Effect observation of endothelin A receptor antagonist BQ-123 improves early brain injury of subarachnoid hemorrhage in rats via PI3 K-Akt signaling pathway

Zhao Yaning; Zhao Xu; Li Jianmin; Xue Chengjing

doi:10.3969/j.issn.1672-5921.2016.05.006

Abstract：Objectives To investigate the treatment effect of endothelin A receptor antagonist BQ-123 on early brain injury of subarachnoid hemorrhage (SAH ) in rats and its mechanism. Methods According to the random number table method,120 SD rats were divided into four groups:a sham operation (sham),a SAH,a high-dose BQ-123 (75 μg/ kg),and a low-dose BQ-123 (50 μg/ kg)(n = 30 in each group). A rat model was induced by using the injection of blood into cisterna magna twice. After establishing models at hours 6,24,72,and 144,the rats were further divided into four subgroups. Light and electron microscopes were used to observe the changes of the morphological structure in hippocampal area. Immunohistochemistry and RT-PCR were used to detect the expression levels of phosphoinositide 3 kina (PI3-K),protein kinase B (PKB/ Akt),and mammal target of rapamycin (mTOR). Results (1)In the process of model making,7 rats died and 1 model did not meet the criteria and was excluded from the SAH group. Six rats died in the high-dose BQ-123 group and the low-dose BQ-123 group respectively. One rat in each group did not meet the criteria and was excluded. The rats were included in the final statistical analysis:30 in the sham group,22 in the SAH group,23 in the high-dose BQ-123 group,and 23 in the low-dose BQ-123 group. (2)Compared with the sham group,the expression levels of PI3-K,AKt and mTOR were increased signifi-cantly (all P < 0. 05). Compared with SAH group,the hippocampal neuronal morphology and structure damage were alleviated in the low-dose BQ-123 group. The number of surviving neurons at each time point was increased ([132 ±18],[110 ±16],[84 ±13],[92 ± 10]cells/ HP,all P < 0. 05). The tensile force values of rats were increased at each time point and the learning and memory function were improved. The expression levels of PI3-K and Akt were further increased (all P < 0. 05). The expression level of mTOR was decreased (all P < 0. 05). (3)Compared with the low-dose BQ-123 group,the morphological and structural damage of hippocampal neurons were alleviated. The number of surviving neurons at each time point ([153 ±20],[131 ± 18],[137 ±19]and [135 ± 17]cells/ HP)was increased (all P < 0. 05). The tensile force values of the rats were increased at each time point. The learning and memory function of the animals were improved. The expression levels of PI3-K (3. 8 ± 0. 8,8. 9 ± 2. 4,8. 6 ± 2. 4,and 6. 2 ± 2. 0)and Akt (4. 86 ± 1. 74, 8. 64 ± 1. 62,7. 94 ± 1. 70,and 6. 48 ± 1. 58)were further increased (all P < 0. 05). The expression levels of mTOR (2. 89 ± 0. 26,2. 14 ± 0. 18,1. 94 ± 0. 17,and 1. 62 ± 0. 12)were decreased (all P < 0. 05). Conclusions BQ-123 has as a good therapeutic effect for early brain injury after SAH. Its mechanism may be associated with the regulation of PI3-K/ Akt signaling pathway.