To investigate the effect and mechanism of genistein on early brain injury (EBI) following subarachnoid hemorrhage (SAH).

A total of 156 male C57BL/6J mice were selected and the mouse SAH model was established using intravascular puncture. Pre experiment: 72 mice were selected and set at two time points of 24 and 72 h, with 36 mice at each time point. Mice at each time point were randomly divided into 6 groups: Sham group, SAH group, solvent group (SAH+Vehicle), low dose group (genistein 5 mg/kg), medium dose group (genistein 15 mg/kg), and high dose group(genistein 30 mg/kg), with 6 mice in each group. The SAH grading, neurological function, and brain water content at 24 and 72 h after SAH were evaluated to determine the optimal injection dose of the drug. After that, 54 mice were randomly divided into three groups: Sham group, SAH group and SAH+genistein group, with 18 mice in each group. The permeability of blood-brain barrier was measured by measuring the extravasation of Evans blue. Tunel staining was used to observe cell apoptosis. Western blot was used to verify the expression of apoptosis-related proteins and blood-brain barrier related proteins. Then, 30 mice were randomly divided into 5 groups, including Sham group, SAH+Vehicle group, SAH+genistein group, SAH+genistein+DMSO group, SAH+genistein+Sirtinol group, with 6 mice in each group. Western blot was used to verify the protein levels of SIRT1, p53 and AC p53.

(1) At 24 and 72 h after SAH, the bleeding volume score and brain water content of the medium and high dose groups were significantly reduced compared to the solvent group, while the Garcia score and balance beam experiment score were significantly increased. Among them, the effect of the medium dose group was the most significant. Therefore, 15 mg/kg of genistein was selected for subsequent experiments. (2) After 24 h of SAH, compared with the SAH group, the Evans blue exudation in the SAH+genistein group decreased, and the protein expression of ZO-1, Occludin, and Claudin-5 increased, with statistical significance (P<0.05). The results of Tunel staining and Western blot analysis showed that compared with the SAH group, the SAH+genistein group had a lower neuronal apoptosis rate, decreased expression of apoptotic proteins Caspase-3, Cleared Caspase-3, and Bax, and increased expression of anti apoptotic protein Bcl-2, with statistical significance (P<0.05). (3) After 24 h of SAH, compared with the SAH+Vehicle group, the SAH+genistein group showed a significant increase in SIRT1 protein expression, while the expression of p53 and AC p53 proteins decreased significantly, with statistical significance (P<0.05); Compared with the SAH+genistein+DMSO group, the SIRT1 protein expression in the SAH+genistein+Sirtinol group significantly decreased, while the expression of p53 and AC p53 proteins significantly increased, with statistical significance (P<0.05).

Genistan can regulate SIRT1/p53 signaling pathway, reduce cerebral edema and neuronal cell apoptosis, and improve EBI after SAH in mice, which has significant therapeutic significance for SAH.