Traumatic brain injury (TBI) is a major reason for temporary or permanent dyskinesia and cognitive impairment of the organism. Generally, TBI induces subsequent neuroinflammation to assist cell debris removal and tissue repair and regeneration after injury. However, overactivation or long-term activation of immune cells will exacerbate nerve damage or death, cause cognitive dysfunction, and ultimately lead to neurodegenerative diseases. Therefore, secondary damage caused by persistent inflammation is a key component of TBI pathological process. As the main metabolite of anaerobic glycolysis, lactate is increased after TBI and participates in brain inflammation as an important immune regulatory molecule rather than a metabolic waste. Importantly, histone lysine lactylation as a novel type of histone post-translational modifications (HPTM) derived from lactate allows lactate to participate in the regulation of complex immunopathophysiological processes of the central nervous system after TBI. Further study on the process of histone lactylation and its immune regulation mechanism during TBI may provide new insights for early intervention and improvement of TBI prognosis. Thus, the authors reviewed the role of histone lactylation in the immune regulation of TBI, so as to further elucidate the mechanism of TBI and the explore new warning and prevention measures from the perspective of HPTM.

Objective:To investigate the changes of cognitive function in non-fatal drowning rats after blast-induced traumatic brain injury (bTBI).Methods:Eighty SD rats were divided into normal group, bTBI group, drowning group and bTBI plus drowning group according to the random number table, with 20 rats per group. Rats in normal group were not injured. In bTBI group, bTBI was established in a BST-I biological shock tube with a pressure of 4.0 MPa in the driving section. In drowning group, rats were subjected to non-fatal drowning by falling into the water with temperature of 18 ℃ and depth of 30 cm from the height of 1 m and were taken out quickly after swimming to exhaustion. After being injured in a biological shock tube, rats in bTBI plus drowning group were immediately forced to drowning using the same method. On day 3 post-injury, the neurocognitive function was evaluated by elevated plus maze and Morris water maze tests. Morphological changes of neurons in CA1 and CA3 regions of hippocampus were observed by Nissl staining, and the number of surviving neurons were counted. The concentrations of hippocampal neurotransmitters glutamate, γ-aminobutyric acid (GABA), glycine and endoplasmic reticulum stress (ERS) related glucose-regulated protein 78 (GRP78) and caspase-12 were examined by ELISA analysis. Levels of B-cell lymphoma-2 (Bcl-2), Bcl-2 associated protein (Bax) and caspase-3 were detected by Western blotting. The ratio of Bcl-2 to Bax was calculated as well.Results:In elevated plus maze test, the percentage of open arm entry and number of head-dipping behaviour were decreased in bTBI plus drowning group compared with normal and bTBI groups at 3 days after injury ( P<0.05 or 0.01), with no statistical difference from those in drowning group ( P>0.05). The number of head-dipping behaviour in drowning group was lower than that in bTBI group ( P<0.05). In Morris water maze test, bTBI plus drowning group showed increased target latency on the third and fourth days of spatial acquisition training and decreased number of crossing the target area and percentage of swimming time in the target quadrant during probe trials as compared with normal group ( P<0.05 or 0.01), but there was no statistical difference among bTBI, drowning and normal groups (all P>0.05). Nissl staining showed that the neurons in the CA1 and CA3 regions of hippocampus in normal group were arranged neatly with clear Nissl bodies at 3 days after injury, while the other groups showed different degrees of injury. In contrast with normal group, the neurons in the CA1 and CA3 regions of hippocampus in all other groups were decreased with the lowest number in bTBI plus drowning groups ( P<0.05 or 0.01). In ELISA analysis, the level of hippocampal glutamate in bTBI plus drowning group was higher than that in all other groups at 3 days after injury and the level in bTBI injury and drowning groups was higher than that in normal group ( P<0.05 or 0.01); the level of hippocampal glycine in bTBI plus drowning group was lower than that in normal group ( P<0.05), but there was no statistical difference among bTBI, drowning or normal groups (all P>0.05); the concentration of hippocampal GABA had no statistical difference among all groups (all P>0.05). In addition, the concentration of GRP78 in bTBI injury, drowning and bTBI injury plus drowning groups were increased compared with normal group ( P<0.05 or 0.01), but did not statistically differ from each other (all P>0.05). The concentration of caspase-12 in drowning and bTBI plus drowning groups were increased compared with normal group ( P<0.05 or 0.01), but was not statistically different from each other ( P>0.05), and its concentration in bTBI plus drowning group was increased compared with bTBI group ( P<0.05). In Western blotting, the level of Bcl-2 in bTBI plus drowning group was decreased compared with all other groups at 3 days after injury, and the level in bTBI and drowning groups were decreased compared with normal group, but a much lower level was observed in drowning group than that in bTBI group ( P<0.05 or 0.01); the level of Bax in bTBI plus drowning group was increased compared with all other groups at 3 days after injury, and the level in drowning group was increased compared with normal group ( P<0.05 or 0.01), with no statistical difference between bTBI and drowning groups ( P>0.05). The ratio of Bcl-2 to Bax in bTBI plus drowning group was decreased compared with all other groups, while the ratio in bTBI and drowning groups were decreased compared with normal group, showing a much lower level in drowning group than that in bTBI group ( P<0.05 or 0.01). Also, the level of caspase-3 in drowning and bTBI plus drowning groups were increased compared with normal and bTBI groups ( P<0.05 or 0.01), but there was no statistical difference between drowning and bTBI plus drowning groups ( P>0.05). Conclusions:Non-fatal drowning can aggravate hippocampal neuron damage in bTBI rats and cause memory, emotion and other cognitive dysfunction. The mechanism may involve the imbalance of hippocampal neurotransmitters glutamate and glycine, which activates the downstream pro-apoptotic pathway through ERS in the early stage of injury to induce hippocampal neuron apoptosis.

Objective To explore the expression and change of ski-interacting protein (SKIP) in rats after spinal cord injury. Methods A total of 60 adult female Sprague-Dawley rats were randomly divided into sham group (n=30) and spinal cord injury (SCI) group (n=30), each group was further divided into five time points including one day, three days, five days, seven days, and 14 days with six rats in each time points. The model was established at T10 with modified Allen's technique, and the sham group only bit the lamina of rats. The hindlimbs behavior was assessed with Basso-Beattie-Bresnahan (BBB) score at each time point. The pathological changes of spinal cord neurons were detected with Nissl staining. The expression of SKIP were observed with immunofluorescence staining. Results The BBB scores were signif-icantly lower in each time point in SCI group than in the sham group (t>48.267, P<0.001). Compared with the sham group, Nissl bodies in the cytoplasm of spinal cord neurons began to disintegrate, coalesce and irregularly distribute, the neurons began to degenerate and die on the fifth day, and the damage deteriorated on the 14th day. Immunofluorescence staining showed that SKIP expression was mainly expressed in the gray matter of the spinal cord and little expressed in the white matter. The expression of SKIP gradually increased after SCI, and reached a peak on the fifth day (t=-17.035, P<0.001) and decreased significantly on the 14th day (t=3.853, P<0.05). Conclusion SKIP may be a new signaling molecule, which play an important role in neuronal apoptosis after SCI.

Objective To explore the expression and the changes of ski with time in the injured spinal cord in rats. Methods Sixty adult female Sprague-Dawley rats were randomly divided into sham group (n=30) and injury group (n=30), each group were further divided into 1 week, 2 weeks, 4 weeks, 8 weeks and 12 weeks subgroups, with 6 rats in each subgroup. Spinal cord injury at T10 was established with modi-fied Allen's technique (10 g × 25 mm) in the injury group. The hindlimbs behavior of rats was rated with Basso-Beattie-Bresnahan (BBB) scores 1 day, 3 days, 1 week, 2 weeks, 4 weeks, 8 weeks and 12 weeks after spinal cord injury. Three rats in each subgroup were stained with HE staining to observe the pathological changes of the spinal cord and the formation of cavity. The other 3 rats were analyzed with im-munofluorescence staining of ski and semi quantitative analysis. Results The BBB scores of each time point were less in the injury group than in the sham group (P<0.05). Necrosis was the major pathological change in the injury groups 1 and 2 weeks after injury;cystic cavity completely formed 4 weeks after injury, with dense scar tissue around it;there was no significant change in the cavity and scar 8 and 12 weeks after injury, however, the adjacent spinal cord was obviously thinner. Ski expressed little in the normal spinal cord, and expressed more and more after injury, peaked at 8 weeks and decreased then. Ski was mainly observed in white matter in the sham group and 12 weeks injury subgroup, which was in gray matter 2, 4 and 8 weeks after injury. Ski was highly expressed around the cavity in injury center and formed high expression band. Conclusion Ski expresses after spinal cord injury in rats, that may be associated with the activation and prolif-eration of astrocytes and the formation of glial scar.

Objective To explore the learning and memory impairment and pathology in hippocampus in rats after spinal cord contu-sion. Methods 36 adult female Sprague-Dawley rats were randomly divided into sham group (n=18) and spinal cord injury group (n=18). Spinal cord injury model at T10 was established with modified Allen's technique (10 g × 25 mm). The hindlimbs behavior of rats was rated with Basso-Beattie-Bresnahan (BBB) scores once a week for 5 weeks. They were tested with motor evoked potentials (MEP) and Morris wa-ter maze 5 weeks after injury. The pathology of hippocampus was detected with HE staining 1 week, 3 weeks and 5 weeks after injury, 4 rats in a group, repectively. Results The BBB scores were significantly lower in the spinal cord injury group than in the sham group at each time point (P<0.05). The latencies of both N1 and P1 wave of MEP were significantly longer in the spinal cord injury group than in the sham group (P<0.001), while the amplitudes were significantly less (P<0.001). For the Morris water maze, the latency of arrival platform were sig-nificantly longer in the spinal cord injury group than in the sham group (P<0.001), and the time in target was significantly less (P<0.001), with more systematic positioning or annular positioning, while the sham group with more space-based positioning. Morphologically abnor-mal cells in hippocampus gradually increased since the first week after injury, with the decrease of cells survival, while it was normal in the sham group. Conclusion Spinal cord contusion can cause learning and memory impairment in rats, which may be related to injury in hippo-campus.

Objective To study the differentiation and proliferation ability of the spinal neural stem cells (NSCs) at different gestational ages in fetal rats. Methods Sprague-Dawley fetal rats were divided into group A (12 days of pregnancy), group B (14 days of pregnancy) and group C (16 days of pregnancy). NSCs were separated with enzyme-assisted microdissection. The diameter and numbers of NSCs balls were measured at different time. The cell growth curve was drawn with CCK8 colorimeter. NSCs were identified with BrdU/Nestin immunohistochemical staining. They were induced with 10% fetal bovine serum for 10 days, and the expression of β-tubulinⅢ and glial fibrillary acidic protein was detected with immunocytochemistry. Results There were cells expressed BrdU, Nestin, β-tubulinⅢ and GFAP in all the group. The most cells (22.74±0.79%) expressed β-tubulinⅢ in the group B, but no significant difference between group B and group C. The cell vitality on the 5th day of third-generation neural stem cells was the most in group B. Conclusion For enzyme-assisted microdissection, it may obtain more neurons to isolate the neural stem cells from 14 days of pregnancy pregnant rats.

Objective To observe the effects of valproic acid (VPA) on function recovery of injuried spinal cord with transplanted neural stem cell in adult rats. Methods 96 SD rats were divided into 4 groups randomly: the injury group, VPA group，NSCs group and NSCs+VPA group. All rats were hemi-sected at T10 level. The rats in VPA group were injected with VPA 300 mg/kg·d introperitoneally twice a day. Those in NSCs group were transplanted with absorbable gelatin sponge absorbing the identified NSCs. Those in NSCs+VPA group were dealed the same as those in NSCs group, and injected with VPA 300 mg/kg·d introperitoneally twice a day. They were assessed with Basso-Beattie-Bresnahan(BBB) scale and electrophysiology examination in 2nd, 4th and 8th week. The nuclear yellow retrograde tracing and DIL anterograde tracing were performed in 8th week. Results The number of neurons traced with DIL and nuclear yellow of NSCs+VPA group were more than that of other groups. The BBB scores and indexes of electrophysiology examination of NSCs+VPA group improved more than other groups, especially the motor evoked potentials. Conclusion VPA promotes neural stem cells transplant to repair the function of injuried spinal cord in adlut rats.

Objective To observe the differentiation of neural stem cells(NSC)into neurons under different astrocytes feeding layers.MethodsThe NSC purified from primary cultured clones and labeled by DAPI in serum-free media were plated in different feeding layers:cyto-plasma astrocytes and fibrous astrocytes respectively with Neural Basal(NB)media.After 10 d,immunohistochemistry with antibody NF-200 was taken to calculate the percents of neurons by 20 fields of vision chosen randomly.The differentiated neurons were stained with AchE and labeled with Fura-3AM.ResultsThe ratios of differentiated neurons in cyto-plasma and fibrous astrocytes were 72% and 43% respectively.In most differentiated neurons the AchE staining was positive and had the activity of Ca2+ stimulated by medicine.ConclusionThe cyto-plasma astrocytes can induced NSC differentiated into neurons,especially into active motor neurons,which can be chosen for a new seeding cells in the nervous tissue engineering.

Objective To observe the regulative effect of high dose of glucocorticoid (GC) on protein synthesis and mRNA transcription of corticotropin-releasing hormone (CRH) in paraventricular hypothalamic nucleus (PVN) so to ascertain whether there exists difference upon effect of GC either at high dose or at normal dose. Methods A total of 60 Wistar rats were divided into five groups, ie, blank control group, 10 -6 mol/L dexamethasone (DEX) group, 10 -9 mol/L DEX group, 9 g/L saline group and group that was treated with 10 -4 mol/L RU486 first and then with 10 -6 mol/L DEX. The drugs were given through femoral vein. CRH protein expression was measured by means of immunohistochemistry and laser confocal scanning microscophy (LCSM); CRH mRNA transcription level was investigated by in situ hybridization. Results There appeared positive CRH mRNA granules in cytoplasm of PVN after administration with 10 -6 mol/L DEX for 20 minutes but could be seen positive fluorescent granules of CRH protein 30 minutes later, which was reversed at an in advance blockage of GR, as was free in 10 -9 mol/L DEX group, 9 g/L saline group and blank control group. Conclusions High dose of GC can up regulate CRH gene expression in PVN and differs much from the traditional effect of GC at normal dose, as may be due to that high dose of GC exerts effects depending on membrane glucocorticoid receptor but normal dose of GC dose via iGR.

Objective To probe the mechanism of anticonvulsant by melatonin from the angle of neurotransmitter.Methods Rat status epilepticus(SE) model was induced by pilocarpine(PILO).?-aminobutyric acid(GABA) content and glutamin acid decarboxylase(GAD)67 mRNA expression was detected at 6,48,72 h,and 7 d in the hippocampus of post-SE rats.The effect of melatonin on these changes was observed.Results GABA content was significantly lower in the hippocampus than in control(P