Hippocampal Warburg Effect Mediates Hydrogen Sulfide-induced Regulation Of Microglia Polarization And Improvement Of Depressive-like Behaviors In Parkinson Disease Rats

[Background and Objective]Depression is the most common complication of Parkinson's disease.At present,there is still a lack of effective drug for treatment of PD-associated depression.Hydrogen sulfide?H₂S?is a novel neuronal signaling molecule with neuromodulatory effects.We have previously demonstrated that H₂S attenuates depressive-like behaviours and that H₂S up-regulates the hippocampus Warburg effect in the PD rat model.It has been confirmed that Warburg effect regulates microglia polarization and that microglia polarization plays important role in depressive-like behaviours.In the present work,we will explore whether H₂S attenuates the depression-like behavior in PD rats by modulating the microglia polarization and whether the hippocampus Warburg effect mediates the improvement of depression-like behavior and the modulation of microglial polarization induced by H₂S in PD rats.[Methods]1.Establish a PD rat model by subcutaneous injection of rotenone?ROT?on the back of the neck.2.Novelty-suppressed bean test?NSFT?,forced swimming test?FST?and tail suspension test?TST?were used to evaluate the depression-like behavior of rats;Elevated plus-maze test?EPMT?was used to evaluate the anxiety-like behavior of rats;open field test?OFT?was used to evaluate the spontaneous activity of rats.3.The immunofluorescence technique was used to detect the average fluorescence intensity of Iba1.4.Western blot detection of the level of Induction nitric oxide synthase?iNOS?and Arginase-1?Arg-1?,Chitinase 3-like 3?Ym-1?expression.5.The Griess reagent detects the Nitric Oxide?NO?content.6.The ELISA kits detect the IL-1?,TGF-?1,IL-4 content.[Results]1.H₂S antagonizes depression-like behaviors in the ROT-induced PD ratsSodium hydrosulfide?NaHS,30 and 100?mol/kg/d,i.p.,4 w?,a H₂S donor,significantly decreased the latency to the first bite of food in NSFT and decreased the duration of immobility time of ROT-induced PD rats in the TST.NaHS?30 and 100?mol/kg/d,i.p.,4 w?significantly decreased the duration of immobility of ROT-induced PD rats in the FST.NaHS?100?mol/kg/d,i.p.,4w?markedly increased the number of entries into the open arm of ROT-induced PD rats,while the number of total arm entries among groups was no change significantly in the EPMT.There was no significant difference in the total distance of rats in the OFT.These results indicated that H₂S ameliorates the depressive-like behaviors in the ROT-induced PD rats.2.H₂S modulates the microglial polarization in the hippocampus of ROT-induced PD ratsNaHS?30,100 mol/kg,i.p.,4 w?significantly reduced the average fluorescence intensity of Iba-1 in the hippocampus of ROT-induced PD rats,indicatting that H₂S inhibits the activation of microglia in the hippocampus of ROT-induced PD rats.NaHS?30,100?mol/kg,i.p.,4 w?significantly reduced the expression of iNOS and the contents of NO and IL-1?in the hippocampus of ROT-induced PD rats,and significantly increased the expressions of Arg-1 and Ym-1 as well as the contents of TGF-?1and IL-4in the hippocampus of ROT-induced PD rats.These results indicated that H₂S improves the microglia M2 polarization in the hippocampus of ROT-induced PD rats.3.Inhibiton of Warburg effect by 2DG abolishes the inhibitory action of H₂S in the depression-like behaviors of ROT-induced PD ratsIn NSFT,2-DG?3?g/w,icv,3 w?reversed the shortening effect of NaHS?100?mol/kg,ip,4 w?on the feeding latency of ROT-induced PD rats,and 2-DG had no effect on the feeding latency of rats.In FST and TST,2-DG?3?g/w,icv,3 w?significantly reversed NaHS?100?mol/kg,ip,4w?-decreased the immobility time of ROT-induced PD rats.In EPMT,2-DG?3?g/w,icv,3 w?significantly reversed NaHS?100?mol/kg,ip,4w?-increased the percentage of entering the open arm in the ROT-induced PD rats,but did not affect the total number of entering the open and closed wall of ROT-induced PD rats.2-DG?3?g/w,icv,3 w?did not affect the spontaneous activity of rats.These results indicate that inhibition of Warburg effect abolishes the inhibitory effect of H₂S on the depression-like behaviors in ROT-induced PD rats.4.Inhibiton of Warburg effect by 2DG reverses the improving effect of H₂S on the microglia M2 polarization in the hippocampus of ROT-induced PD rats2-DG?3?g/w,icv,3 w?reversed NaHS?100?mol/kg,ip,4w?-inhibited the activation of hippocampal microglia in the ROT-induced PD rats.2-DG?3?g/w,icv,3 w?reversed NaHS?100?mol/kg,ip,4w?-reduced the expression of iNOS as well as the contents of NO and IL-1?,and abolished NaHS?100?mol/kg,ip,4 w?-increased the expressions of Arg-1and Ym-1 as well as the contents of TGF-?1 and IL-4,in the hippocampus of ROT-induced PD rats.The above results indicated that inhibited Warburg effect reverses the improving effect of H₂S on the hippocampal microglia M2 polarization of ROT-induced PD rats.[Conclusion]1.H₂S attenuates the depression-like behavior in the ROT-induced PD rats;2.Promoting the hippocampal microglial M2 polarization is involved in the antagonizing role of H₂S in the depression-like behaviors of ROT-induced PD rats;3.Hippocampal Warburg effect mediates H₂S-induced the improvement of depression-like behavior and the promotion of hippocampal microglia M2-polarization in the ROT-induced PD rats.