[Comparison of distributions of muscle injection and intravenous administration of human mesenchymal stem cells in denervated muscles of the sciatic nerve injured rats].

OBJECTIVE

To explore the better transplantation way of mesenchymal stem cells (MSCs) in neuromuscular disease and its effect on the recovery of injured sciatic nerves.

METHODS

Human MSCs were isolated, cultured and fluorescently labeled in vitro. Fifty-four rats were randomly divided into MSC intramuscular (ims), intravenous (iv) and saline administration groups. The sciatic nerve was crashed by hemostat for 5 min. MSCs (10(6)) were injected 3 days after injury. Sciatic nerve function index (SFI), electromyography and muscle biopsy specimens were recorded on ad3, ad7,ad14, ad21, ad28 and ad60.

RESULTS

Denervation and regeneration of nerves were observed in the three groups. Spontaneous activity and action potential happened earlier in ims injected group than in the other two groups. The nerve conductivity velocity of ims injected rats was significantly faster than those of the iv group and the control group on d14 [(32.27+/-7.42) m/s,(22.92+/-7.34) m/s and (17.67+/-5.52) m/s; F=5.661,P=0.042]. On d60, the conduction velocity was about the same among the three groups(P>0.05). However, compound muscle action potential (CMAP) amplitude in ims injected group was significantly higher as compared with the other two groups[ims injected group (12.50+/-2.06) mV, iv group (1.50+/-0.20) mV, control group (10.13+/-4.04) mV, F=6.347, P=0.033]. The MSCs were able to be observed only in ims injected tissues 3 weeks after implantation (A large number of small undifferentiated cells were found outside the myofibers and some were found between the cells.) The atrophy of gastrocnemius in ims injected group was much less severe than that of the other 2 groups. The diameter of muscle fibers was significantly longer on d60 (F=4.537, P=0.021).

CONCLUSION

Intramuscular injection of MSC was well distributed in denervated muscle, which provides a new way of nerve regeneration in the rat model of sciatic nerve injury.