Restoration of gastrocnemius muscle in MDX mice of different age after injury and implantation of xenogenic muscle tissue.

The intensity of regeneration of crossed gastrocnemius muscle was evaluated in two groups of mdx mice of different age 2 weeks after implantation of crushed muscle tissue from newborn rats into the wound defect area. The effect of xenoplasty manifested in increased weight of the damaged muscle. The effect was observed in mice aging 12–16 weeks but not in those aged 40–48-weeks. Structural changes in the skeletal muscle tissue intrinsic of mdx mice and augmenting with age were detected in intact mice before the experiment. Activity of muscle fiber regeneration in intact and injured muscle of 40–48-week-old mice was significantly lower than in 12–16-week-old ones. Myoblasts of the xenogenic transplant retained viability in recipient muscles for at least 2 weeks. Post-traumatic regeneration was stimulated in only 12–16-week animals. Xenoplasty was ineffective in older animals and even somewhat enhanced the destructive processes in the muscle. It seems that age-specific regeneration activity of the recipient skeletal muscle tissue should be taken into consideration in the development of effective strategy of cell therapy for progressive muscular dystrophy.