| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2000: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1999: ¥2,700,000 (Direct Cost: ¥2,700,000)
|
|---|
| Research Abstract |
Spinal cord injuries (SCI) were induced in rats in order to investigate the sequential changes of the paralytic skeletal muscle fibers, especially features from ATPase histochemistry and myosin heavy chain (MHC) isoforms biochemistry were observed in the atrophied muscle fibers.
In ATPase activity, type I muscle fibers remarkably decreased toward 5 weeks after the transection, and type II muscle fibers increased accompanying with the decrease of type I in soleus (SOL). In extensor digitorum longus (EDL), type I muscle fibers were not detected 3 weeks after the transection, but they appeared 5 weeks after the transection again.
We also examined the myosin heavy chain (MHC) compositions of SOL and EDL by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). In the wet weight (mg/BW) of SOL was decreased 40-50% compared with that of control, whereas the weight of EDL showed no significant change. The type I MHC of SOL muscles in SCI rats gradually reduced toward 5 weeks after the operation, while type IId and IIb MHC appeared andnincreased after 1 week. In the EDL muscles of SCI, type IIb MHC was slightly decreased and type IId increased after 3 weeks.
In the single fiber analysis, the number of pure type MHC-expressing fibers distinctly decreased in the SOL muscle after 3 weeks, whereas hybrid fibers markedly increased. In the EDL muscles of SCI, the number of pure type fibers slightly decreased toward 5 weeks after operation. These results indicate that the differences of MHC-expression between SOL and EDL after SCI is due to the muscle condition whether lengthened or shortened, and the original MHC compositions differing SOL from EDL.
|
