ABSTRACT
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.
ABSTRACT
Objective:To explore the effects of enriched environment combined with melatonin on learning and memory function and DNA oxidative damage in senescence accelerated mouse prone 8 (SAMP8) mice.Methods:Twenty-four 6-month-old SPF healthy male SAMP8 mice were randomly divided into model group, enriched environment group, melatonin group and enriched environment+ melatonin group, with 6 mice in each group. Six homologous SAMR1 mice of the same age were used as the control group. The mice in the enriched environment group and the enriched environment+ melatonin group were fed in the enriched environment. At the same time, the mice in the melatonin group and the enriched environment+ melatonin group were subcutaneously injected with melatonin (8 mg /(kg·d)) once a day for 28 d. The mice in the model group, the control group and the enriched environment group were subcutaneously injected with an equal volume of 0.9% sodium chloride solution once a day for 28 days. Aging score was used to evaluate the aging of mice. Morris water maze and Y maze tests were used to evaluate the learning and memory ability of mice. The cell morphology of hippocampus in mice was observed by hematoxylin-eosin staining, and the level of Aβ 1-42 protein in hippocampus of mice was detected by immunohistochemical staining. The levels of γ-H2A histone family member X(γ-H2AX) and 8-hydroxy-2 deoxyguanosine(8-OHdG) proteins in hippocampus of mice were detected by Western blot and Enzyme-linked immunosorbent assay. SPSS 25.0 statistical software was used to process the data. One-way analysis of variance was used for comparison among multiple groups, and LSD- t test was used for further pairwise comparison. Results:(1)There was a statistical difference in aging scores among the 5 groups of mice after intervention ( F=126.4, P<0.01). After intervention, the aging scores of mice in the enriched environment group, melatonin group, and enriched environment+ melatonin group were lower than that in the model group (all P<0.05), and the score of the enriched environment+ melatonin group was significantly lower than that in the enriched environment group ( P<0.05). (2)The time and group interaction, group main effect and time main effect of the escape latency among the 5 groups of mice were statistically significant ( F=11.2, 799.9, 121.8, all P<0.01). From day 2 to day 4, the escape latencies of mice in the enriched environment group, melatonin group and enriched environment+ melatonin group were significantly lower than that in the model group (all P<0.05). There was a statistically significant difference in the target quadrant residence time and cross-platform times among the 5 groups ( F=70.38, 48.83, both P<0.01). The target quadrant residence time and cross-platform times of mice in the enriched environment group, melatonin group, and enriched environment+ melatonin group were significantly higher than that in the model group (all P<0.05). (3) There were significant differences in the total number of alternations and correct rates among the 5 groups ( F=291.328, 113.482, both P<0.01). The total numbers of alternations and correct rates in melatonin group ((29.46±3.75)times, (53.16±3.47)%) and the enriched environment+ melatonin group((32.57±3.52)times, (58.60±4.13)%)were significantly higher than those in the model group ((18.62±3.96)times, (43.61±3.92) %)(all P<0.05). (4)The results of hematoxylin-eosin staining and immunohistochemistry staining showed that compared with the model group, the cell structure and morphology of the hippocampus of mice in enriched environment group, melatonin group, and enriched environment+ melatonin group were significantly improved, and the expression of Aβ 1-42 was significantly reduced (all P<0.05). (5) There were statistically significant differences in the levels of γ-H2AX and 8-OHdG proteins in the hippocampus of the 5 groups of mice ( F=78.09, 117.20, both P<0.01). The levels of γ-H2AX and 8-OHdG of mice in the enriched environment+ melatonin group ((1.37±0.26), (4.79±0.35)pg/μg) were significantly lower than those in the enriched environment group ((2.83±0.25), (7.23±0.41)pg/μg) and the melatonin group ((2.43±0.22), (6.69±0.28)pg/μg) (all P<0.05). Conclusion:Both enriched environment and melatonin can significantly improve the learning and memory function of SAMP8 mice, and the combined treatment effect is more significant.The mechanism may be related to the reduction of DNA oxidative damage in hippocampus.