Investigation On The Protective Effects Of Histone Deacetylase Inhibitor (HDACi) On Brain Ischemia

Aim To investigate the effects of permanent occlusion of the middle cerebral artery（p-MCAO）on theprotein acetylation and the involvement of protein modification in the brain damage. To studythe protective effects and the underlying mechanism of histone deacetylase inhibitor (HDACi),trichostatin A (TSA),on oxygen/glucose deprivation (OGD) injured PC12cells;Methods:Permanent occlusion of the middle cerebral artery(MCAO) was established in micewith an nylon monofilament.The establishment of p-MCAO model is determined byNeurological Severity Scores (NSS) and TTC staining. The neurologic deficit score wasdetermined according to Zea-Longa’s Standard, and the infarct volume was assessed withsoftware (Adobe Photo Shop5.0) after TTC (2,3,5-Triphenyl Tetrazolium Chloride) staining.The effective concentration of HDACi in vivo was determined by the decrease of neurologicdeficit score and infarct volume.The alternation of protein acetylation level and Arginase1expression in mice brain in different time point was detected by Western blot. PC12OGD injurymodel was established by using cobalt chloride (CoCl2) and glucose-free medium, and treatedby TSA. Cell viability was measured by MTT assay, cell apoptosis and necrosis was observed byPI and Hoechst staining, fluorescence microscope were applied to determine the change ofMitochondrial membrane potential in each group, flow cytometry detection and fluorescencemicroscope were applied to determine the reactive oxygen species in each group,the change ofcell protein acetylation level in varying degrees and the impact of TSA treatment on PC12OGDinjury model were analyzed by Western blot. Results Western blot analyses showed that theexpression of acetylation-protein and Arginase1was reduced in the mice subjected to p-MCAOat different time points; the expression of acetylated proteins and Arginase1reduced in theischemic mice subjected to1h p-MCAO and reduced significantly in the ischemic micesubjected to24h p-MCAO. Compared with control,80nmol L-1TSA significantly improvedcells viability and reduced intracellular reactive oxygen species (p＜0.05); Western blot analysesshowed that the expression of acetylation-protein is reduced in PC12OGD model, moreover,TSA treatment could increase the protein acetylation. Conclusion Acetylated protein and theexpression of Arginase1are reduced in the ischemic mice subjected to p-MCAO, which maycause the brain edema and energy metabolic. TSA significantly protects the OGD injured PC12 cells, the possible underlying mechanisms may be relate to maintain or increase the acetylationlevel of the energy metabolism enzymes, whereby to keep the PC12cells from the injury inducedby OGD.