Prolonged exercise training increases intramuscular lipid content and perilipin 2 expression in type 1 muscle fibres of patients with type 2 diabetes.

Abstract

The aim of the present study was to investigate changes in intramuscular triglyceride (IMTG) content and perilipin 2 expression in skeletal muscle tissue following 6 months of endurance type exercise training in type 2 diabetes patients, 10 obese, male type 2 diabetes patients (age 62 ±1 y, BMI 31±1 kg/m2) completed 3 exercise sessions per week, consisting of 40 min ofcontinuous endurance type exercise at 75% VO2 peak, for a period of 6 months. Muscle biopsies collected at baseline and after 2 and 6 months of intervention were analysed for IMTG content and perilipin 2 expression using fibre type specific immunofluorescence microscopy. Endurance type exercise training reduced trunk body fat by 6±2% and increased whole-body oxygen uptake capacity by 13±7% (P<0.05). IMTG content increased two-fold in response to the 6 months exercise training in both type I and type II muscle fibres (P<0.05). A three-fold increase in perilipin 2 expression was observed from baseline to 2 and 6 months of intervention in the type I muscle fibres only (1.1±0.3, 3.4±0.6, and 3.6±0.6% fibre stained, respectively; P<0.05). Exercise training induced a 1.6-fold increase in mitochondrial content after 6 months of training in both type I and type II muscle fibres (P<0.05). In conclusion, this is the first study to report that prolonged endurance type exercise training increases the expression of perilipin 2 alongside increases in IMTG content in a type I muscle fiber type specific manner in type 2 diabetes patients.