ABSTRACT
Objective:To observe the ferroptosis in hippocampal neurons of rats with multiple cerebral concussion (MCC) .Methods:Ninety clean grade male Wistar rats with a body mass of (250±10) g were randomly divided into control group (12 rats) and model group (78 rats) according to the random number table method. The rat of MCC model was prepared by hitting the frontotemporal lobe of rats with free fall method once a day for 3 consecutive days.Then the MCC model rats were randomly divided into 12 h, 24 h, 48 h, 72 h, 7 d and 14 d groups with 12 rats in each group. The balance beam experiment was used to detect the motor coordination function of the rats. The levels of interleukin-β(IL-1β), interleukin-6(IL-6), serum glutathione (GSH), neuron-specific enolase (NSE) in serum of rats were detected by ELISA.The content of iron ion in hippocampus was detected by colorimetry. The mRNA and protein levels of glutathione peroxidase 4(GPX4), ferritin heavy (FTH) and ferritin light(FTL) in the hippocampus were detected by RT-PCR and Western blot. Prussian blue staining was used to observe the iron deposition in brain tissue.The ultrastructural changes of hippocampal neurons and mitochondria were observed by transmission electron microscope. SPSS 24.0 statistical software was used for one-way ANOVA among groups, and LSD test was used for multiple pairwise comparison.Results:In the balance beam experiment, the passing time and motor coordination score of rats in each group were significantly different ( F=30.08, 60.34, both P<0.05). The passing time and motor coordination score of rats in the 48 h group ((87.00±4.74) s, (4.75±0.43)) were significantly higher than those in the control group ((35.13±6.99) s, (0.75±0.23)) (both P<0.05). There was significant difference in the total iron ion content, Fe 2+ content and Fe 3+ content in hippocampus of rats in each group ( F=25.20, 94.42, 40.25, all P<0.05), and the content of Fe 2+ in hippocampus of 48 h group was significantly higher than that of the control group ((10.17±0.05) ng/μL, (8.65±0.01) ng/μL)( P<0.05). In the results of RT-PCR and Western blot, the mRNA and protein levels of GPX4, FTH and FTL in hippocampus of each group were significantly different ( F=37.94, 82.09, 49.01, 71.63, 28.94, 15.78, all P<0.05). The mRNA level and protein level of GPX4 ((1.09±0.01), (0.23±0.01) )and FTL ((1.60±0.03), (0.64±0.02)) in 24 h group were significantly higher than those of the control group (GPX4: (1.00±0.02), (0.17±0.01)), FTL: ((1.00±0.04), (0.32±0.01))(all P<0.05). The mRNA level and protein level of FTH ((0.24±0.03), (0.07±0.01)) in 24 h group were significantly lower than those of the control group((1.00±0.01), (0.67±0.03))(both P<0.05). The results of electron microscope showed that the hippocampal neuronal cells of the model rats were reduced, the nucleolus was broken and the nuclear membrane was shrunk in varying degrees, the mitochondria were swollen and deformed and there were vacuoles, and the cristae in the mitochondria decreased or disappeared. Conclusion:The levels of inflammatory reaction and oxidative stress in the multiple cerebral concussion model rats increase, and the hippocampal neurons show the characteristics of ferroptosis, especially at 24 h and 48 h.
ABSTRACT
Objective To detect the long term effect of pure and multiple concussions on spatial cognitive of rats.Methods One hundred and eighty 7-week-old Spragne-Dawley male rats with weight of 280 ± 30g were chosen and randomly divided into a control group and a concussion group.The cerebral concussion was induced in the rats using a metallic pendulum striker concussive device.After the first strike,the brain injury group was randomly divided into a pure cerebral concussion(PCC)group and a multiple cerebral concussion(MCC) group.After the second strike,the MCC group was randomly divided into two-fold cerebral concussion(2MCC) group and three-fold cerebral concussion(3MCC) group.The striking interval was 24h.One,3 and 6 months after trauma,their cognitive function was tested using Morris water maze.Results One month later after injury,there was no significant difference in the escape latency between the control group and PCC group.Significant differences in the measurement were observed between the control/PCC group and 2MCC group on the 7th day after the injury,also between the control/PCC and 3MCC groups on the 6th and 7th day.And there were significant differences between the 2MCC and 3MCC groups on the 6th and 7th days.The non-platform test did not observe any significant differences among the four groups.Three months after injury,there was still no significant difference between the control group and PCC group,PCC and 2MCC groups,as well as 2MCC and 3MCC groups in the escape latency.However,there was significant difference between the control group and 2MCC group on the 5th,6th and 7th days,between the control group and 3MCC group on the 4th,5th,6th and 7th days,as well as between PCC group and 3MCC group on the 6th and 7th days.In the non-platform test,there was no significant difference between the control group and PCC group,between PCC group and 2MCC group,as well as between 2MCC group and 3MCC group.However,2MCC and 3MCC groups spent significantly less time in the former platform quadrant,when compared with the control group and 3MCC group spent significantly less time than PCC group.Six months after injury,significant differences in the escape latency were observed between the control group and PCC group on the 6th and 7th days,and 2MCC group on the 5th,6th and 7th days,also and 3MCC groups on the 2nd,3rd,4th,5th,6th and 7th days,still between PCC group and 2MCC group on the 6th and 7th days,as well as between PCC group and 3MCC group on the 4th,5th,6th and 7th days.Moreover,there was significant difference between 2MCC and 3MCC groups only on the 7th day.In the non-platform test,PCC group,2MCC group and 3MCC group spent significantly less time in the former platform quadrant compared with the control group.Moreover,in this test significant differences were found between PCC group and 2MCC/3MCC group,but not between 2MCC group and 3MCC group.Conclusion With the increase of cerebral concussion times,earlier and more serious damage of spatial cognition will appear,with a significant cumulative effect in rats.Such rat model can be used to study the pathological changes of cognitive impairment in chronic traumatic encephalopathy.
ABSTRACT
Objective To observe learning and memory behavior changes of one time cerebral concussion called pure cerebral concussion(PCC)and three times cerebral concussion called multiple cerebral concussion (MCC)after injured 24 days in rats.Methods A metallic pendulum striker device was deployed to duplicate PCC and MCC model in SD rata which were the complete closed head injury model.The animals were divided into PCC and MCC groups at random.One control group was used,each group has eight animals(n=8).One 8-arms radial maze was used to assessed each animal's capabilities,that is,spatial reference memory,working memory,spirited activity and take in food.Results Compared with control group,there were some significance(P＜0.05)in both experiment groups post injury,that was,(1)The food intake decreased,PCC group from the 1st to the 11th day(from 0.00±0.00 to 2.62±1.76)after injury,MCC group from the 1st day to the 24th day(from 0.00±0.00 to 0.75±1.48)after injury.(2)Spirited activity depressed,PCC group on the 1st to the 7th,13rd day(from 4.87±1.24 to 10.0±2.39)after injury,MCC group on the 1st to 8th,22nd day(from 4.25±5.03 to 9.37±4.20)after injury.(3)The spatial reference memory was lower in early then gradually increased,PCC group on the 1 st to 7th day(from 0.50±0.75 to 3.O0±1.06)after injury,MCC group from the 1st to 19th day(from 1.88±2.10 to 2.50±2.44)after injury.(4)The working memory was delaying damaged,PCC group from the 1st to the 6th day and the 10th to the 23rd day(from 0.00±0.00 to 4.25±3.05)after injury,MCC group on the 1～4th,6th,9～13th,15th,16th,19th～22nd day(from 0.25±0.46 to 3.12±2.87)after injury.Conclusion The injured rata'capability of spatial reference memory,working memory,spirited activity and food intake were obviously damaged after CC,and the MCC group's capability of spatial reference memory,spirited activity and food intake was worse than PCC group.