Pattern of Reinnervation in Denervated Rat Gastrocnemius Muscle by Various Procedures of Reinnervation

Kwon, Yong Jin; Kim, Jun Yonug; Moon, Young Il; Lee, Il Woo; Lee, Byung Joo; Roh, Hwan Jung; Goh, Eui Kyung; Chon, Kyong Myong; Wang, Soo Geun; Hwang, So Min

Abstract

BACKGROUND AND OBJECTIVES: We tried to investigate the effectiveness of various methods of reinnervation including nerve-muscle pedicle transfer, nerve anastomosis, nerve implantation. MATERIALS AND METHOD: Forty Sprague-Dawley rats were used. Control group and experimental groups each consisted 5 rats, as follows: a denervated tibial nerve without reinnervation (control), a common peroneal nerve and 2X2 mm tibialis anterior muscle pedicle grafted to the denervated gastrocnemius muscle after the removal of epimysium (group I), a common peroneal nerve and 4X4 mm tibialis anterior muscle pedicle grafted to the denervated gastrocnemius muscle after the removal of epimysium (group II), a common peroneal nerve and 2X2 mm tibialis anterior muscle pedicle grafted to the denervated gastrocnemius muscle after removal of epimysium and part of muscle (group III), a common peroneal nerve and 4X4 mm tibialis anterior muscle pedicle grafted to the denervated gastrocnemius muscle after removal of epimysium and part of muscle (group IV), a common peroneal nerve and 2X2 mm tibialis anterior muscle pedicle inserted to the denervated gastrocnemius muscle (group V), a common peroneal nerve inserted to the denervated gastrocnemius muscle (group VI), and anastomesed common peroneal nerve to distal tibialis nerve (group VII). Electromyography, muscle contraction power study, histotological analysis and counting of motor end-plate were applied for estimating the reinnervation of denervated muscle.
RESULTS
In motor nerve conduction studies, Group VII and III showed significantly higher amplitude of the compound muscle action potentials than other groups. In muscle contraction power studies, Group VII and III showed significantly powerful contraction. In histological analysis, group VII and III showed less muscle atrophy. The motor end-plate count was more in the groups VII, III, I, V, VI, II and IV in order.
CONCLUSION
Nerve anastomosis and 2X2 mm nerve-muscle pedicle transfer showed more successful regeneration of denervated muscle than other reinnervation methods including nerve implantation.