Therapeutic Effect And Mechanism Of Tanshinone ⅡA On PTSD Rats

Objectives:Post-traumatic stress disorder(PTSD)is a serious mental disorder associated with persistent stress.Although the pathogenesis of PTSD is still unclear,patients often show cognitive dysfunction accompanied by inflammation.The currently available drugs are not effective.A large number of clinical and preclinical animal studies have shown that Tanshinone ⅡA(TSA),a natural product isolated from the traditional Chinese herbal medicine Salvia miltiorrhiza,has a rapid and lasting improvement effect on PTSD-like symptoms such as depression and anxiety,suggesting that it may have a certain effect on PTSD,but there is no relevant report.Therefore,in this study,the PTSD rat model was prepared by single-prolonged stress(SPS)method,and the effects of TSA on the behavior,pathological morphology,inflammation and synaptic plasticity of PTSD rats were observed,and the therapeutic effect of TSA on PTSD and its potential mechanism were preliminarily discussed.Methods:1.Establishment and grouping of PTSD animal modelThe PTSD animal model was established by the SPS method,and the modeled PTSD rats were randomly divided into the modeling group(SPS),TSA low-dose group(TSA-L),TSA medium-dose group(TSA-M)and TSA high-dose group(TSA-H),with12 rats in each group.The three treatment groups were given different doses(40 mg/kg,80mg/kg,120mg/kg)of TSA intervention,while a normal control group(Control),Control group and SPS group were given equal amounts of solvent,and all groups were administered continuously by gavage for 14 days.2.Effect of TSA on behavior of PTSD ratsThe behavioral improvement effects of different doses of TSA on PTSD rats were examined by open field,elevated cross maze and Morris water maze experiments.3.Histopathological effects of TSA on hippocampus of PTSD ratsHE and Nissl staining were used to observe the effects of different doses of TSA on the morphology and number of neurons in the hippocampal region of PTSD rats,and to investigate the protective effects of different doses of TSA on hippocampal neurons in PTSD rats.4.Effect of TSA on inflammation of hippocampal neurons in PTSD ratsWestern blot technique was used to examine the expression of IκBα protein,NF-κB p65 protein and i NOS protein in the hippocampus of each group of rats to investigate the effect of TSA on neuroinflammation in the hippocampus of PTSD rats.5.Effects of TSA on axonal regeneration and synaptic plasticity in the hippocampus of PTSD ratsThe expression of Synapsin I,NF200 and Neu N proteins in the hippocampus of rats was detected by immunofluorescence or Western blot technique,and the changes of axons and dendrites were observed by Golgi staining.The expression of Nogo-A,Ng R,Rho A and ROCK Ⅱ in the hippocampus of each group was examined by immunofluorescence or Western blot technique to investigate the effect of TSA on axonal regeneration and synaptic plasticity in the hippocampus of PTSD rats.Results:1.The PTSD model was successfully established by SPS method.The behavioral data showed that the intervention of middle and high dose TSA could significantly improve the autonomic behavior,anxiety and tension of PTSD rats,and showed better spatial learning and memory ability,but the effect of TSA-L group was not obvious.2.Pathological staining results showed that TSA,especially at medium and high doses,could significantly improve the distribution,morphology and number of hippocampal neurons in PTSD rats,with some neuroprotective effects.3.The expression levels of IκBα,NF-κB p65 and iNOS proteins in the hippocampus of rats in the SPS group were higher than those in the Control group,indicating that SPS triggered the activation of inflammatory signals in the hippocampal region of rats.The expression levels of IκBα,NF-κB p65 and i NOS proteins were significantly downregulated by TSA administration intervention,indicating that TSA could effectively inhibit the inflammatory response in the hippocampal region of PTSD rats.4.Compared with the Control group,the expression levels of Synapsin I,NF200 and Neu N in the hippocampal region of the SPS group rats were significantly reduced,while TSA reversed the expression changes of these three proteins,and the results of Golgi staining showed that TSA increased the axonal complexity and dendritic spine density of neurons in the hippocampal region of PTSD rats.This indicates that TSA can promote the regeneration of hippocampal neurons and improve the synaptic plasticity in the hippocampus of PTSD rats to some extent.5.Compared with the Control group,the Nogo-A signaling pathway was significantly activated in the hippocampus of SPS rats,while TSA effectively inhibited the activation of the Nogo-A signaling pathway,suggesting that TSA may promote axonal regeneration of neurons in the hippocampus of PTSD rats through inhibiting the Nogo-A signaling pathway and thus improve synaptic plasticity.Conclusion:1.TSA significantly improved anxiety-like behavior and spatial learning memory deficits in PTSD rats,and had neuronal protective effects in PTSD rats.2.The behavioral ameliorative effects of TSA in PTSD rats may be achieved by inhibiting inflammation in the hippocampal region,improving synaptic plasticity and promoting axonal regeneration.