Protective effect of hydrogen sulfide on acute cerebral vasospasm in subarachnoid hemorrhage models

Abstract

Objective To study the effect of hydrogen sulfide (H2S) on acute cerebral vasospasm (CVS) after subarachnoid hemorrhage (SAH) and explore its mechanism. Methods (1) A total of 48 adult male SD rats were randomly allocated into a normal group, a SAH group, a low dose NaHS group and a high dose NaHS group (n=12). Rat models of SAH were induced by injecting autologous blood into the prechiasmatic cistern. Rats in the later two groups were given 0.7 mg/kg and 2.8 mg/kg NaHS, respectively, 0.5 h after modeling. Neurological scale scores were assessed 24 h after modeling; HE staining, TUNEL and immunohistochemical double-staining were employed to detect the morphology of approximated A2 blood vessel of anterior cerebral artery (ACA), tube wall thickness and endothelial cell apoptosis, respectively. (2) Brain microvascular endothelial cells (BMECs) were chosen and divided into blank control group, 100 μmol/L OxyHb prevention group, 25 μmol/L NaHS pretreatment group and 100 μmol/L NaHS pretreatment group. The cells were collected and observed 24 h after treatment, and then, the number of endotheliocytes was counted, and the Caspase-3 protein expression was detected by Western blotting. Results (1) The neurological scale scores (8.5±2.4) were significantly lower, the vessel wall ([43.5±6.2] μm) was significantly thickened, the lumen area ([30 488±938) μm2) was obviously reduced, and the number of TUNEL positive cells ([36.51±11.45]%) was remarkably increased in the SAH group as compared with those in the normal group (16.1±1.7, [25.8±3.5] μm, [51707±1422] μm2 and [2.86±0.75]% in turn, P<0.05). The neurological scale scores (11.6±1.9 and 15.4±2.3) were significantly higher, the vessel wall ([34.7±3.7] and [31.7±4.6] μm) was significantly thinned, the lumen area ([41 463±1104] and [45 244±1217] μm2) was obviously increased, and the number of TUNEL positive cells ([17.14±5.36] and [8.10±4.62] %) was remarkably reduced in the low dose NaHS group and high dose NaHS group as compared with those in the SAH group (P<0.05). The neurological scale scores in high dose NaHS group were significantly higher than those in the low dose group and the number of TUNEL positive cells was signficantly smaller than that in the low dose group (P<0.05). (2) The number of apoptotic endothelial cells ([40.56±9.85] %) and the expression of Caspase-3 (0.395±0.122) in OxyHb prevention group were significantly larger/higher than those in the blank control group (P<0.05). The number of apoptotic endothelial cells and the expression of Caspase-3 in the low dose group ([16.65±6.35]% and [0.223±0.083]) and high dose group([14.12±6.65] % and [0.208±0.104]) were obviously reduced as compared with those in the OxyHb prevention group, with significant differences (P<0.05). Conclusion H2S can effectively expand cerebral vasospasm, and its vasoprotective mechanism may be through inhibiting vascular endothelial cell apoptosis. Key words: Subarachnoid hemorrhage; Acute Cerebral vasospasm; Hydrogen sulfide; Endothelial cell; Apoptosis