Correlation between serum IL-1beta levels and cerebral edema extent in a hypertensive intracerebral hemorrhage rat model

Background: Interleukin-1beta (IL-1beta) is a pro-inflammatory cytokine that is increased following hypertensive intracerebral hemorrhage (ICH), potentially related to neural damage by cerebral edema. Objective: To investigate the correlation between post-ICH serum IL-1beta and cerebral edema in a hypertensive rat model. Methods: We used 30 successful ICH male spontaneously hypertensive rats (SHR) subjected to autologous blood infusion and displaying behavioral abnormalities (ICH group), and 30 sham-operated rats. Cerebral edema was assessed at 8, 16, 24, 48, 72, and 120 hours using dry and wet right hemisphere weighing, and serum IL-1beta levels were determined by enzyme-linked immunosorbent assay (ELISA). Nonlinear regression was performed between serum IL-1beta levels and cerebral edema extent at different time intervals after ICH. Results: No significant difference was observed in preoperative blood pressure between the two groups. In ICH rats, behavioral abnormalities were observed at all time points except at 120 hours Intracerebral hemorrhage rats exhibited significantly increased serum IL-1beta levels between 16 and 72 hours, and increased cerebral edema between 24 and 72 hours (all P < 0.05 vs sham-operated rats), but no significant differences were found in the sham-operated group. Serum IL-1beta and cerebral edema in the ICH group returned to baseline by 120 hours Serum IL-1beta levels were positively correlated with cerebral edema (r = 0.906, P = 0.001). Conclusion: Serum IL-1beta was related to cerebral edema extent in hypertensive ICH rats, which may eventually be useful as an indicator for progression of cerebral edema after ICH, and contributing to the choice of a treatment strategy.