Skeletal muscle subsarcolemmal mitochondrial dysfunction in high-fat fed rats exhibiting impaired glucose homeostasis.
OBJECTIVE
To investigate whether changes in body energy balance induced by long-term high-fat feeding in adult rats could be associated with modifications in energetic behaviour and oxidative stress of skeletal muscle subsarcolemmal (SS) and intermyofibrillar (IMF) mitochondrial populations.


METHODS
Adult rats were fed low-fat or high-fat diet for 7 weeks.


METHODS
Body energy balance and composition analysis together with plasma insulin and glucose level determination in the whole animal. Oxidative capacity, basal and induced proton leaks as well as aconitase and superoxide dismutase activities in SS and IMF mitochondria from skeletal muscle.


RESULTS
High-fat fed rats exhibit increased body lipid content, as well as hyperinsulinemia, hyperglycaemia and higher plasma non-esterified fatty acids. In addition, SS mitochondria display lower respiratory capacity and a different behaviour of SS and IMF mitochondria is found in the prevention from oxidative damage.


CONCLUSIONS
A deleterious consequence of decreased oxidative capacity in SS mitochondria from rats fed high-fat diet would be a reduced utilization of energy substrates, especially fatty acids, which may lead to intracellular triglyceride accumulation, lipotoxicity and insulin resistance development. Our results thus reveal a possible role for SS mitochondria in the impairment of glucose homeostasis induced by high-fat diet.
Lionetti
L
L
Section of Physiology, Department of Biological Sciences, University of Naples Federico II, Via Mezzocannone 8, I-80134 Naples, Italy.
Mollica
M P
MP
Crescenzo
R
R
D'Andrea
E
E
Ferraro
M
M
Bianco
F
F
Liverini
G
G
Iossa
S
S
D000818:Animals; D001823:Body Composition / Q000502:physiology; D004041:Dietary Fats / Q000008:administration & dosage; D002149:Energy Intake; D004734:Energy Metabolism; D018149:Glucose Intolerance / Q000378:metabolism*; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D008931:Mitochondria, Muscle / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D009765:Obesity; D018384:Oxidative Stress / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D012508:Sarcolemma / Q000378:metabolism
D004041:Dietary Fats