RESUMO
Objective:To investigate the effects of ceftriaxone(CTX) on nuclear factor erythroid 2-related factor 2(Nrf2)/glutathione peroxidase 4(GPX4) pathway and ferroptosis in early brain injury in rats with subarachnoid hemorrhage(SAH).Methods:Forty-eight clean grade male SD rats were randomly divided into sham operation group (Sham group), SAH group, SAH+ CTX group and SAH+ CTX+ Nrf2 inhibitor group (SAH+ CTX+ ML385 group) according to the random number table with 12 rats in each group.Seven days before modeling, rats in SAH+ CTX+ ML385 group were injected intraperitoneally with ML385 (30 mg · kg -1) once a day for consecutive 7 days.And 5 days before modeling, rats in SAH+ CTX group and SAH+ CTX+ ML385 group were treated with CTX(200 mg · kg -1) by intraperitoneal injection once a day for five consecutive days.Rats in Sham group and SAH group were intraperitoneally injected with the same amount of 0.9% sodium chloride solution.After 24 hours of modeling, the neurological function score and brain tissue water content of rats in each group were measured.HE staining was used to observe the morphology of neurons in CA1 and CA3 regions of hippocampus.Prussian blue staining was used to observe the iron deposition in cerebral cortex.Spectrophotometer was used to determine the iron content, malonic dialdehyde(MDA) content, glutathione(GSH) content and GPX4 activity in cerebral cortex.Western blot was used to detect the expression levels of Nrf2 and GPX4 proteins in cerebral cortex.SPSS 23.0 was used for statistical analysis.One-way ANOVA was used to compare the mean of multiple groups of samples, and Dunnett- t test was used for further pairwise comparison between groups. Results:There was a statistically significant difference in the neurological function scores of rats in the four groups 24 hours after SAH ( F=48.40, P<0.001). The neurological function score of rats in the SAH group 24 hours after SAH was significantly lower than those in Sham group and SAH+ CTX group (both P<0.05). The brain water content of rats in the four groups 24 h after SAH was statistically significant ( F=49.61, P<0.001). The brain water content of rats in the SAH group 24 h after SAH was significantly higher than that in Sham group and SAH+ CTX group(both P<0.05). There was statistically significant differences in the number of neuronal necrosis in CA1 and CA3 regions of hippocampus in the four groups 24 hours after SAH ( F=17.44, 246.50, both P<0.001). The numbers of neuronal necrosis in CA1 and CA3 regions of hippocampus in SAH group were significantly higher than those in Sham group and SAH+ CTX group, and the numbers of neuronal necrosis in CA1 and CA3 regions of hippocampus in SAH+ CTX+ ML385 group were significantly higher than those in SAH+ CTX group (all P<0.05). Twenty-four hours after SAH, the amount of iron deposited in the cerebral cortex of rats in the four groups was statistically significant ( F=2 363.0, P<0.001). The iron deposition in the cerebral cortex of rats in the SAH group was significantly higher than those in Sham group and SAH+ CTX group (both P<0.05). There were significant differences in iron content, MDA content, GSH content and GPX4 activity in the cerebral cortex of the four groups 24 h after SAH( F=2 380.0, 1 322.0, 789.1, 815.5, all P<0.001). The content of iron and MDA in the cerebral cortex of rats in SAH group were significantly higher than those in Sham group, while the content of GSH and the activity of GPX4 were significantly lower than those in Sham group (all P<0.05). The content of iron and MDA in the cerebral cortex of rats in SAH+ CTX group were lower than those in SAH group, and the content of GSH and the activity of GPX4 were higher than those in SAH group (all P<0.05). At 24 h after SAH, the expression levels of Nrf2 and GPX4 protein in the cerebral cortex of the four groups were statistically significant ( F=888.7, 1 556.0, both P<0.001). The protein expression levels of Nrf2 (0.382±0.014) and GPX4 (0.329±0.019) in the cerebral cortex in SAH group were lower than those in Sham group ((0.746±0.009), (0.953±0.009)) (both P<0.05). The expression levels of Nrf2 (0.631±0.006) and GPX4 (0.833±0.008) protein in the cerebral cortex in the SAH+ CTX group were significantly higher than those in the SAH group (both P<0.05). The expression levels of Nrf2 (0.427±0.009) and GPX4 (0.525±0.011) protein in the cerebral cortex in SAH+ CTX+ ML385 group were significantly lower than those in SAH+ CTX group (both P<0.05). Conclusion:Ceftriaxone may inhibit ferroptosis during EBI in SAH rats by regulating Nrf2/GPX4 signal axis.