The Inflammatory Effects Of Optimized DNA Vaccines On Parkinson’s Disease Mice

Objective：1. To investigate the inflammatory response characteristics of chronicmodel mice of Parkinson’s disease damaged by MPTP.2. To evaluate the neuroprotective effect of optimized DNA vaccine bypreventive immunization for Parkinson’s disease mice.3. To investigate the inflammatory response characteristics ofParkinson’s disease mice immunized with optimized DNA vaccine, andfurther evaluate the efficacy and safety of the optimized DNA vaccine.MethodsFirst, we extracted and prepared sufficient optimized DNA vaccineand empty plasmid by endotoxin plasmid extraction kit. All the C57BL/6normal mice were randomly divided into normal control group, the PBSmodel group, empty plasmid model group, optimized DNA vaccine modelgroup.Then, in the tibialis anterior muscle of posterior limbs of the mice ineach group, were respectively injected PBS, PBS, empty plasmid,pVAX1-IL-4/SYN-B100ul for preventive immunizations, all three times. Three weeks after the last injection, the latter three groups were injectedMPTP to build chronic Parkinson’s disease model mice, the normal controlgroup injected with the same volume of PBS. After the last administration,the mice were observed for behavioral changes; we investigated theexpression level of TH, CD11b and COX-2in substantia nigra ofexperimental mice by immunohistochemistry and western blot methods,detected the mRNA levels of TNF-α, IL1-β inflammatory cytokine byRT-PCR.Results1. In the preventive immunization stage, we found no abnormalbehavior of mice. In the model building process of Parkinson’s disease,each model mice appeared upturned and stiff tail, shaking and rigid limbs,reduced and slow activity, curled and tremulous body and other types ofParkinson’s disease symptoms. Compared with the the PBS model groupand the empty plasmid model group, the behavioral abnormalities inoptimized DNA vaccine model mice significantly improved.2. The result of immunohistochemistry showed significantly reducedTH neurons in the substantia nigra of each model mice, the western blotresult was consistent to the immunohistochemistry result. The TH lostdegree in Optimized DNA vaccine model group significantly reducedcompared with the PBS model group and the empty plasmid model group,the difference was statistically significant. 3. Immunohistochemistry showed a large number of CD11b, COX-2inflammatory cell infiltration in each model mice substantia nigra andcortex and other parts; compared with the the PBS model group and theempty plasmid model group, the CD11b, COX-2cells and proteinexcretion levels in optimize DNA vaccine model group were significantlyreduced, and the difference was statistically significant.4. The TNF-α, IL1-β inflammatory mediators mRNA levels inoptimized DNA vaccine model group were more decreased than the PBSmodel group and empty plasmid model group, the difference wasstatistically significant.ConclusionFrom these results we can conclude that each model group miceexhibited class of Parkinson symptoms, TH neurons decreasedsignificantly indicating that the chronic MPTP modle wassuccessfully constructed; inflammatory cells and inflammatorymediators expression in the model group showed that MPTP inducedinflammatory response in mice brain substantia nigra; optimized DNAvaccine to prevent immunization can reduce the TH neuron loss inmodel mice and inhibit the inflammatory cells and inflammatorycytokines, these results investigate that the optimized DNA vaccineshow neuroprotective and anti-inflammatory effects on chronic MPTPmodle mice, laid a theoretical foundation for further studies to optimize the DNA vaccine.