Fiber optic Raman spectroscopy for the evaluation of disease state in Duchenne muscular dystrophy: An assessment using the mdx model and human muscle

Introduction/Aims

Raman spectroscopy is an emerging technique for the evaluation of muscle disease. Here, we evaluate the ability of in vivo intramuscular Raman spectroscopy to detect the effects of voluntary running in the mdx model of Duchenne muscular dystrophy (DMD). We also compare mdx data to muscle spectra from human patients.

Methods

Thirty 90-day old mdx mice were randomly allocated to an exercised group (48 hours access to a running wheel) and an unexercised group (n=15 per group). In vivo Raman spectra were collected from both gastrocnemius muscles and histopathological assessment subsequently performed. Raman data were analysed using principal component analysis fed linear discriminant analysis (PCA-LDA). Exercised and unexercised mdx muscle spectra were compared to human DMD samples using cosine similarity.

Results

Exercised mice ran an average of 6.5km over 48 hours which induced a significant increase in muscle necrosis (P=0.03). PCA-LDA scores were significantly different between the exercised and unexercised groups (P<0.0001) and correlated significantly with distance run (P=0.01). Raman spectra from exercised mice were more similar to human spectra than those from unexercised mice.

Discussion

Raman spectroscopy provides a readout of the biochemical alterations in muscle in both the mdx mouse and human DMD muscle.