Metabolic and electrophysiological changes in rabbit skeletal muscle during ischaemia and reperfusion.
OBJECTIVE
To clarify the effects of ischaemia and reperfusion on membrane potential of skeletal muscle in rabbits, and to study its correlation with the energy charge and the lactate content.


METHODS
Open experimental study.


METHODS
20 isolated rabbits' hindlimbs.


METHODS
The femoral arteries were cannulated and the limbs amputated at the level of the hip joint. Blood was removed by thorough perfusion with Ringer's solution. Below knee fasciotomies were done, and the whole limbs were immersed in Ringer's solution during periods of ischaemia. Reperfusion was with a modified Krebs' buffer with Dextran T70 saturated with oxygen.


METHODS
Measurements of membrane potential; ATP, ADP, and AMP concentrations; and lactate concentrations in muscles after 1 (n = 8), 2 (n = 4), 4 (n = 4), or 6 (n = 4) hour periods of ischaemia followed by a 2 hour period of reperfusion compared with those in 4 limbs that were made ischaemic for 8 hours and not reperfused.


RESULTS
During the first hour of ischaemia the membrane potential decreased from -90 mV to -63 mV and the energy charge remained unchanged at 0.9. After 8 hours of ischaemia the membrane potential had decreased to -20 mV, the energy charge was 0.2, and the lactate content had increased by a factor of 12. During reperfusion the membrane potential was restored only in limbs that had been subjected to 1 hour of ischaemia, whereas energy charge was also restored in those subjected to 2 and 4 hours of ischaemia. The lactate content decreased during reperfusion in all limbs.


CONCLUSIONS
Assessment of membrane potential is more sensitive than that of energy charge as an indicator of recovery of skeletal muscle after a period of ischaemia followed by reperfusion.
Oredsson
S
S
Department of Surgery, Helsingborg Hospital, Sweden.
Arlock
P
P
Plate
G
G
Qvarfordt
P
P
D000244:Adenosine Diphosphate / Q000032:analysis; D000249:Adenosine Monophosphate / Q000032:analysis; D000255:Adenosine Triphosphate / Q000032:analysis; D000818:Animals; D004734:Energy Metabolism; D007511:Ischemia / Q000378:metabolism* / Q000503:physiopathology*; D007773:Lactates / Q000378:metabolism*; D008564:Membrane Potentials / Q000502:physiology*; D008839:Microelectrodes; D009132:Muscles / Q000098:blood supply / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology*; D011817:Rabbits; D012044:Regression Analysis; D015424:Reperfusion; D013997:Time Factors
D007773:Lactates; D000249:Adenosine Monophosphate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate