Effects of anoxia on cellular damage in the incubated mouse diaphragm.

Satisfactory ultrastructural integrity of the mouse diaphragm was maintained in vitro in modified Krebs-henseleit saline for 3h when the rate of oxygenation was 2.8 ml sec-1 (95% O2 + 5% CO2). Hypoxic (O2 = 1.6-2.0 ml sec-1) or anoxic (95% N2 + 5% CO2) conditions triggered typical Ca-triggered myofilament damage, believed to be induced by a rise in [Ca]i. It was unaffected by omission of Ca from the saline, but the muscle was protected at 7.8 degrees C. 'High-O2' gassing (10 ml sec-1) also caused a characteristic, but different, damage with swollen sarcoplasmic reticulum and spacing of the myofibrils.