Objective: Magnetic resonance spectroscopy (MRS) has the potential to noninvasively delineate early biochemical changes in denervated muscle. In this study, we examine metabolic changes in denervated rat facial muscles using quantitative invitro 1H and 31P MRS.
Methods: Forty male Wistar rats were subjected to transection of the facial nerve trunk on the left and sham exposure on the right, and allowed to recover. The animals were then reoperated at 1, 2, 4, or 8 weeks after the initial procedure. EMG of the facial muscles and facial nerve conduction studies were performed at both time points, and facial muscles were harvested from normal and control sides at the second procedure. Perchloric acid extracts of facial muscles were then prepared for analysis using MRS.
Results: The results showed a progressive time-dependent decrease in Cr, PCr, Pi, ATP, and ADP all on the transected side.
Conclusion: This study is an important step in the development of clinically relevant noninvasive methods of assessing and quantifying degeneration in nerve-muscle systems.