Effects Of Thymopoietin On The Immune System In Mice Model Of Myasthenia Gravis

Objective:To establish an animal model of myasthenia gravis(EAMG)onC57BL/6 mice with synthetic polypeptide of acetylcholin receptor(AchR)α-subunit residues 125-147,and to study the effects of thymopentin(TP-5)on theimmune system of the EAMG model. Method:40 C57BL/6 mice were randomlydivided into normal control,adjuvant control,EAMG control and TP-5 treatmentgroups,each with 10 mice. The synthetic polypeptide was emulsified in completeFreund's adjuvant (CFA) then injected peritonealy into the animals in EAMG controland TP-5 treatment groups to induce the EAMG conditions which were assessed bythe clinical scores of Lennon, grip strength (inverted hang time), immune organ index,serum tidal value of AchR-Ab and serum concentration of IFN-γ. The treatmentefficacy of TP-5 was evaluated by the same parameters in EAMG mice. Results:According to the results of the statistical analysis on the data collected, the invertedhang time of the EAMG group was significanly shorter than the normal control aswell as the CFA control group(P<0.001), the same result was obtained for the serumAchR-Ab concentration (P<0.001). When the clinical scores of Lennon were applied,the successful rate of EAMG induction in this study was 75%. In regard of theefficacy of TP-5 treatment, all the parameters evaluated indicated a significantimprovement of the MG conditions after TP-5 treatment (83.15±11.52 vs. 111.20±21.60,P<0.05 for CD4~+/CD8~+ ratio；0.3484±0.1211 vs. 0.7149±0.1637,P<0.001for AchR-Ab；0.1535±0.0085 vs. 0.1838±0.0131,P<0.001 for IFN-γ；0.00182±0.00034 vs. 0.00220±0.000296,P<0.05 for thymus index and 0.00348±0.00046 vs.0.00397±0.00038,P<0.05 for spleen index). Conclusion:The EAMG model can besuccessfully induced on C57BL/6 mice with the synthetic polypeptide ofAchRα-subunit residues 125-147. The treatment efficacy of TP-5 on MG wasestablished through the evaluation at levels of immune organ index, humoralimmunity, T-cell sub-population, and cellular cytokine.