Long-term hyperglycaemia decreases gastrocnemius susceptibility to permeability transition

Eur J Clin Invest 2010; 40 (4): 319–329 Abstract Background Hyperglycaemia-resulting in mitochondrial bioenergetics’ complications is associated with skeletal muscle dysfunction. The aim of this work was to analyse the effect of long-term severe hyperglycaemia on gastrocnemius mitochondrial bioenergetics, with special relevance on the susceptibility to mitochondrial permeability transition pore (MPTP) opening. Methods Sixteen adult (6- to 8-week-old) male Wistar rats were randomly divided into two groups (n = 8/group): control and diabetic. A single dose (50 mg kg−1) of streptozotocin (STZ) was administrated i.p. to induce hyperglycaemia. In vitro mitochondrial oxygen consumption rates, membrane potential (Δψ) fluctuations, MPTP induction as followed by osmotic swelling and extramitochondrial calcium movements and caspase 9-like activity were evaluated 18 weeks after STZ treatment. Results STZ treatment induced an increase in state 4 and a decrease in the respiratory control ratio with complex I substrates (P