| Background Traumatic brain injury (TBI) is a common neurosurgical acute, which causes motor and sensory dysfunction due to secondary injuries such as nerve cell apoptosis, necrosis and inflammatory response with TBI, seriously affecting the quality of patients’ life. So far there is no effective treatment. Early protection of nerve cells and the control of the inflammatory response after TBI is an important target for clinical drug intervention. Recent extensive studies have demonstrated that VPA (valproic acid) plays essential roles in many aspects of neurotrophic and neuroprotective. On the basis of the establishment of an animal model of closed head injury, we utilized VPA at the early stage to explore the effects of VPA on the recovery of nerve functions of rats with TBI and its mechanismsthrough the investigations of behavioral scores, nerve cell apoptosis, expression changes of HSP70and caspase-3, TNF-α and IL-1β in brain tissue and dynamic changes of TNF-α and IL-1β in brain tissue in this study, providing theory foundations for VPA clinical application on the treatment of TBI.Object We analyzed nerve cell apoptosis, time-course expression changes of HSP70and caspase-3, TNF-α and IL-1β and dynamic alterations of TNF-α and IL-1β in the rats brain tissue after VPA intervention by establishing rat model of closed head injury. The aims in this study are to explore the roles of VPA in antiapoptosis of cells, protecting nerve cells and reducing the inflammatory response of rats with TBI.Methods Healthy male SD rats were randomly divided into normal control group, the simple trauma group and VPA treated group. Rat model of closed head injury was established and then the nerve functions of the rats within each group at different time points were evaluated by Nervous system disease severity score (NSS); Optical microscope and In Situ Nick-End Labeling (TUNEL) were used to observe the morphological changes of the brain tissue detect apoptosis in rat brain tissue, respectively; Immunohistochemical staining (SP method) was utilized to detect the time-course expression of HSP70and caspase-3protein in brain cells within each group; Immunofluorescence was employed to analyze the TNF-a and IL-1β protein expression of brain cells within each group at different time points; Enzyme-linked immunosorbent assay (ELISA) was performed to determine the dynamic changes of TNF-α and IL-1β in brain tissue within each group at different time points, and then these data were statistically analyzed.Results1. Behavior determination:Behavioral scores showed varying degrees of recovery in rats with TBI after VPA treatment. No significantly statistical difference was observed among the three groups in3days post-traumatic (P>0.05); the difference was significant between VPA therapy and simple trauma groups after treatment of7d,14d,21d and28d(P<0.05).2. In Situ Nick-End Labeling (TUNEL) detection:The number of apoptosis positive cells of the rat injury District cortex in simple trauma group and VPA treated group were higher than that of normal control group at each time point. The number of apoptosis positive cells in VPA treated group was lower than that of simple trauma group at each time point. All the differences were statistically significant (P<0.05)3. Immunohistochemical detection:The average gray value of HSP70was lower and caspase-3was higher significantly in VPA treated group compared to simple trauma group at the same time points. Both of the differences were statistically significant (P<0.05).4. Immunofluorescence:The positive cells of TNF-a and IL-1β in brain tissue were less in VPA treated group in contrast to simple trauma group at the same time points. The difference was statistically significant (P<0.05).5. ELISA (enzyme-linked immunosorbent assay) test:The protein concentrations of TNF-α and IL-1β in brain tissue were higher in simple trauma group and VPA treated group in comparison with normal control group at the same time points after modeling and the difference was statistically significant (P<0.05). The protein level of TNF-α and IL-1β in brain tissue were lower in VPA treated group compared to simple trauma group at the same time points after modeling and the difference was statistically significant (P<0.05).Conclusions Neurological function of rats with TBI can be efficiently improved after VPA treatment, which play important roles in the resistance to apoptosis, protecting nerve cells and the relief of inflammatory reactions. |
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