ABSTRACT
Objective To observe the effect of methylprednisolone on the expression levels of aquaporin-4 (AQP-4) and S100 protein in brain tissue of hypertensive intracerebral hemorrhage in rats and to investigate the treatment timing and the possible neuroprotective mechanism of methylprednisolone for hypertensive intracerebral hemorrhage. Methods Sixty-four rats were randomly divided into 3 groups:a sham operation group ( n= 8 ), a control group ( n= 8 ), and a methylprednisolone group ( n= 48 ). The methylprednisolone group was redivided into 2, 4, 8, 12, 24, and 48 hsubgroups (n=8 in each subgroup) according to the modeling to the time intervals of methylprednisolone treatment. Methylprednisolone was administered intraperitoneal y (30 mg/kg fol owed by 15 mg/kg every 6 hours for 3 d) at the corresponding time points in the methylprednisolone group, and the equal volume normal saline was administered intraperitoneal y in the control group. Neurological behavior score was conducted at 24 and 72 h after methylprednisolone treatment. The dry-wet weight method was used to measure hemispheric water content. In situ hybridization and immunohistochemical staining were used to detect the expression changes of AQP-4 mRNA and AQP-4 protein respectively. Double staining immunohistochemistry was used to detect AQP-4 and S100 protein. Results Compared with the sham operation group, the expression level of AQP-4 and brain water content in the control group were significantly increased (al P<0. 05). Compared with the control group, the neurological scores, expression levels of AQP-4 mRNA and protein, as wel as the brain water content in early methylprednisolone subgroups (2 h, 4 h and 8 hsubgroups) were significantly decreased (al P<0. 05). Double staining immunohistochemistry showed that expression levels of AQP-4 and S100 protein in early methylprednisolone subgroups (2 h, 4 h and 8 hsubgroups) were significantly decreased than those in the control group (al P<0. 05). Conclusions Early methylprednisolone may downregulate the expression levels of AQP-4 and S100 protein in the brain tissue after hypertensive intracerebral hemorrhage in rats, and thus attenuate brain edema after intracerebral hemorrhage.