Effects of Asphyxia Preconditioning on the Content of Inflammatory Media in Brain Tissue after Intracerebral Hemorrhage in Rats

Objective To observe the effects of asphyxia preconditioning on water content and the contents of interleukin-6(IL-6), tumor necrosis factor-alpha (TNF-α), superoxide dismutase(SOD) and malondialdehyde(MDA) in perihemotoma tissue after intracerebral hemorrhage(ICH) in rats. Methods Totally 150 male SD rats were randomly allocated into three groups: sham group(Group S, n=50), ICH group(Group I, n=50) and preconditioning group (Group P, n=50). The rats were anesthetized with 10% chloral hydrate 40 mg·kg-1 celiac injection, paralyzed with vecuronium 0.2 mg·kg-1 and mechanically ventilated. The P group were pretreated with four times of preconditioning, by stopping ventilation for 1 min and reventilation for 5 min per circle. Other groups were not pretreated and only mechanically ventilated. One hour later, all the rats were maintained at an adequate respiratory rate(55 breaths/min) and depth, and the endotracheal tube was removed. ICH model was made by stereotactic injection of 50 μL autologous blood into the caudate nucleus in group P and I, or 50 μL saline in Group S. The changes of brain water content in different regions were measured by the wet and dry weight methods. The content of IL-6 and TNF-α in brain tissues were measured with radioimmunoassay and the content of SOD, MDA were assayed by chromatometry at 6 h, 24 h, 48 h and 72 h after ICH. Results As shown in the ipsilateral basal ganglia, the increase of brain water content after ICH of group P(79.96±0.52, 80.49±0.69)% were much lower than that that in group I(81.78±1.49, 83.93±1.12)% at 24 h and 48 h. The differences were significant(P0.05). The contents of IL-6 and TNF-α in brain increased obviously in group I and P at 6h after ICH, peaked at 48 h, and decreased at 72 h. The contents of TNF-α in groupP were greatly lower at 48 h as compared with group I, P0.05. SOD in perihemotoma decreased significantly after ICH in group I and P. As compared with group I at 48 h (141±33 U/mg), SOD in group P (184±22 U/mg) was much higher, P0.05. MDA increased significantly after ICH in group I and P. While the values were much lighter in group P(3.53±1.42, 6.38±1.01 nmol/mg) than that in group I(5.55±0.93, 8.30±1.65 nmol/mg) at 24 h and 48 h, P0.05. Conclusion Asphyxia preconditioning increases the content of IL-6 and SOD, decreases the content of TNF-α and MDA, alleviates brain water content and demonstrates certain cerebral protective effects after ICH in rats.