Preventive and therapeutic effects of proteasome inhibitor MGª²132 on denerª²vated muscle atrophy of rats

    LI Qiang, LUO Zhuoª²Jing, ZHU Jinª²Yu, BI Long, L¦a Rong, MENG Hao, GENG Dan

    Institute of Orthopaedics, Xijing Hospital, Fourth Military Medical University, Xi¬ðan 710033, China

    ¡¾Abstract¡¿ AIM: To investigate the preventive and therapeutic effects of proteasome inhibitor MGª²132 on the denervated muscle atrophy of rats. METHODS: Thirtyª²six SD were randomly diviª²ded into 3 groups, group A: 50 ¦ÌL MGª²132 group; group B: 100 ¦ÌL MGª²132 group; group C: control group, 12 rats in each group. Standard model of denervated gastrocnemius muscle was established in right limb of each rat. 50 and 100 ¦ÌL MGª²132 (concentration 20 ¦Ìmol/L), 100 ¦ÌL PBS were respectively given by intramuscular injection once per day to right gastrocnemius muscle of each rat of group A, B and C. Six rats of the each group were separately sacrificed after the last injection of the 1st and 4th week, and the gastrocnemius was harvested for measurement of atrophy rate of muscle, total proteins of muscle, diameter and cross section area of myocyte. RESULTS: At the 1st week postinjectively, atrophy rate of muscle, total proteins of muscle, diameter and cross section area of myocyte in group A and B were (24.5¡À3.5)% and (18.2¡À3.3)%, (9.98¡À0.68) mg/mL and (10.56¡À0.84) mg/mL, (14.61¡À1.26) ¦Ìm and (14.96¡À1.34) ¦Ìm, (790.25¡À12.26) ¦Ìm2 and (800.28¡À18.98) ¦Ìm2; there were significant differences from group C (P<0.05), and also between group A and B in atrophy rate of muscle (P<0.05). At the 4th week postinjectively, the above indexes were (60.2¡À3.7)% and(52.1¡À4.0)%, (7.04¡À0.70) mg/mL and (7.96¡À0.68) mg/mL, (10.63¡À1.04) ¦Ìm and (12.16¡À0.98) ¦Ìm, (470.48¡À11.14) ¦Ìm2 and (498.47¡À10.34) ¦Ìm2; there were statistic differences from group C (P<0.05), and also between group A and B in the above indexes (P<0.05). CONCLUSION: Denervated muscle atrophy can be partly prevented by proteasome inhibitor MGª²132 in rats, and the effects rely on the dose of MGª²132 and the injection duration. ......