Effect of hypoxic preconditioning on ERS protein, phosphorylated eIF2α, expression in rats after traumatic brain injury

Liu Guangjie; Liu Jiachuan; Wang Jinbiao; Yang Yanyan; Zhang Xing; Wang Chunlin; Tang Hong; Xu Shen

doi:10.11850/j.issn.1009-122X.2016.02.013

Abstract：Objective To explore the effect of hypoxic preconditioning on endoplasmic reticulum stress (ERS) protein, phosphorylated eukaryotic translation initiation factor 2α (P-eIF2α), expression in traumatic brain injury rats. Methods Sprague Dawley rats were randomly divided into control group (n=8), hypoxic preconditioning group (HPC, n=8), traumatic brain injury group (TBI, n=96) and traumatic brain injury after hypoxic preconditioning group (HPCT, n=96).The TBI model of rats were made by modified Feeney's method and hypoxic preconditioning was performed in a hypobaric chamber for 3 days (-50 kPa, 3 h/d) in advance. Immunohistochemistry and Western blotting were used to detect the expression of P-eIF2α. The apoptosis of neurons was detected by TUNEL staining. Results The P-eIF2αprotein appeared in 3 h after traumatic brain injury, and the appearance trended to increase from 6 to 12 h, then achieved its apex in 1 d and the trend decreased from 3 d to 14 d. The difference of appearance in 6 h-7 d was significant between the groups of HPCT and TBI (P<0.05). Apoptosis cells were detected by TUNEL staining, which appeared in 6 h after TBI, then trended to increase from 12 h to 1 d, achieved its apex in 3 d and the trend decreased from 7 d to 14 d. However, in the HPCT group, the apoptosis rate declined obviously in 12 h-7 d after TBI compared with TBI group, and the difference between the two groups was significant (P<0.05). Conclusions Hypoxic preconditioning can selectively inhibit the expression of P-eIF2αprotein in the cortex of rats after TBI, reduce the ERS-related injury, decrease the rate of cell apoptosis, maintain the stability of neuron function.