A correlative study of tumor necrosis factor-α in ischemic brain tissue and brain edema after cerebral ischemia-reperfusion in rats / 国际脑血管病杂志

ABSTRACT

Objective To investigate the relationship between tumor necrosis factor-α (TNF-α) in ischemic brain tissue and bran edema after cerebral ischemia-reperfusion in rats.Methods Eighty four male SD rats were randomly assigned to either a cerebral ischemia reperfusion group (n =44) or a sham-operation group (n =40). A model of middle cerebral artery occlusion for 120 minutes followed by reperfusion was induced in rats using the suture method. The infarct size was determined by 2, 3, 5-triphenyi terazoloride (TTC) staining at 6 h,24 h, 3 d, and 7 d respectively after the reperfusion. Dry-wet weight method was used to measure brain water content and evaluate the extent of brain edema. The enzyme-linked immunosorbent assay (ELISA) was used to detect the concentration of TNF-α in ischemic brain tissue. Results TNF-α level in ischemic brain tissue was increased at 6 h (445.8 ±91.7 pg/ml) after the reperfusion, and reached the peak at day 3 (715.5 ±121.3 pg/ml). There were significant differences compared to the sham-operation group and other time points (all P＜0.001). After that, it was decreased gradually, but it was still higher than that in the shamoperation group at day 7 (478.1 ± 145.5 pg/ml vs. 148.5 ± 101.7 pg/ml, P＜0.005). The initial change of the water content in brain tissue lagged behind the increased TNF-α. It did not increase significantly until 24 h after cerebral ischemia-reperfusion (P ＜0.001). It reached the peak at day 3 (P ＜0.001), and it was still higher than that in the control group at day 7 (P ＜0.05). The evolution of cerebral infarct volume was in accordance with the changes of TNF-α level. Conclusions TNF-α is associated with the changes of brain edema and infarct volume,and it is harmful to brain tissue.