Abstract： Objective To investigate the effect of hypertonic saline on cerebral water content, tumor necrosis factor-α (TNF-α) level and neuronal apoptosis following focal cerebral ischemia-reperfusion (IR) injury in rats and explore the mechanisms involved. Methods Ninety-six rats were randomized equally into 4 groups, namely the shame-operated group, untreated IR injury group, and 4.2% and 7.5% hypertonic saline groups (HS-A and HS-B groups, respectively). In the latter 3 groups, cerebral ischcmia was induced by middle cerebral artery occlusion for 2 h followed by administration of the corresponding treatments. Serum sodium concentration was measured at 5 min before and at 30, 60 and 90 min after the reperfilsion. At 22 h of rcperfusion, the rats were sacrificed after neurological deficit evaluation, and brain edema was assessed by measuring the wet-to-dry weight ratio of the brain tissue. TNF-α expression in the ischemic brain tissue was measured by enzyme-linked immunosorbent assay (ELISA), and the neuronal apoptosis was analyzed using TUNEL assay. Results In the saline-treated rats, serum sodium level increased significantly after saline administration, lasting for 60 min before recovering the normal levels in HS-A group and for over 90 min in HS-B group. Compared with that in the sham-operated group, the brain water content in rats of the IR group increased in both of the hemispheres, but more obviously in the ischemic hemisphere. In the two saline-treated groups, the water content decreased significantly in the bilateral hemispheres, which was especially obvious in the ischemic hemisphere;administration of 7.5% saline resulted in greater water content reduction in the ischemic hemisphere than 4.2% saline. Compared with the IR group, the two saline-treated groups showed significant reduction in TNF-α levels and apoptotic cells in the brain along with decreased neurological deficits. Conclusion Hypertonic saline can ameliorate cerebral focal IR injury by decreasing the cerebral water content, TNF-α level and neuronal apoptosis following the injury.