Systemic effects of single hindlimb burn injury on skeletal muscle function and cyclic nucleotide levels in the murine model.
This study tested the hypothesis that a single hindlimb burn has both local and distant effects. Male CF1 anaesthetized mice were given a full thickness scald burn of 3 per cent total body surface area (BSA) by immersion of their left hindlimb in water at 95 degrees C for 5 s. Muscle tension was measured through twitch analysis. Levels of cyclic adenosine 3'-5' monophosphate (cAMP) and cyclic guanosine 3'-5' monophosphate (cGMP) were analysed by 125I-radioimmunoassay. Measurements were made in gastrocnemei of the ipsilateral burned and contralateral unburned limbs over a 28-day postburn period. Within 1 week the burned limb showed an increase in both tension and a 100-fold increase in levels of cAMP. However, by the end of the second week muscle tension in the burned limb dropped to one-seventh of control values despite persistence of high levels of cAMP. In contrast, the systemic effects were manifested in the unburned contralateral limb which showed tension to undergo a six-fold compensatory increase at the end of the second week with a 75-fold increase in cAMP. By the end of 4 weeks, tension levels of both burned and unburned limbs were attenuated to one-half control values indicating neuromuscular (NM) dysfunction. Nevertheless, cAMP levels remained elevated in both limbs. Levels of cGMP were reduced throughout the 4-week postburn period. Subsequent to the single hindlimb injury both ipsilateral and contralateral gastrocnemei muscles showed elevated levels of total protein content.(ABSTRACT TRUNCATED AT 250 WORDS)
Tomera
J F
JF
Department of Anaesthesiology, Harvard Medical School, Boston.
Martyn
J
J
D000818:Animals; D002056:Burns / Q000150:complications / Q000378:metabolism / Q000503:physiopathology*; D000242:Cyclic AMP / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D004195:Disease Models, Animal; D006614:Hindlimb; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009124:Muscle Proteins / Q000378:metabolism; D009132:Muscles / Q000378:metabolism / Q000503:physiopathology*; D009468:Neuromuscular Diseases / Q000209:etiology / Q000503:physiopathology; D009712:Nucleotides, Cyclic / Q000378:metabolism*
D009124:Muscle Proteins; D009712:Nucleotides, Cyclic; D000242:Cyclic AMP; D006152:Cyclic GMP