Concentrations of free carnosine (a putative membrane-protective antioxidant) in human muscle biopsies and rat muscles

Carnosine has possible functional effects on skeletal muscle contractility, along with membrane-protective, antioxidant effects. We determined tissue free carnosine concentrations in skeletal muscles from patients with neurom uscular diseases and in skeletal and heart muscles from rats of various age s. The effects of age, gender and diagnostic category on free carnosine lev els in patients with neuromuscular diseases were analyzed by a stepwise mul tiple linear regression model. The age of the patients emerged as a signifi cant negative predictor of carnosine concentrations (R = -0.40, P < 0.05). Free carnosine concentrations in rat skeletal muscles also showed a signifi cant negative correlation with the ages of the rats (male rats: R = -0.49, P < 0.05; female rats: R = -0.56, P < 0.05). Only the diagnostic category a myotrophic lateral sclerosis (ALS) emerged as a significant negative predic tor compared to the control group in the stepwise regression model, this wa s confirmed by Wilcoxon Signed Rank Test (P < 0.05). We conclude that the a ge-related decline in muscle mass, strength and function is associated with decreased tissue concentrations of the putative membrane-protective antiox idant carnosine. In addition we found decreased carnosine tissue concentrat ions in ALS. The reduction in carnosine content might be caused by progress ive denervation processes. (C) 1999 Elsevier Science Ireland Ltd. All right s reserved.