Prolonged
tourniquet use can lead to tissue
ischemia and can cause progressive muscle and nerve
injuries. Such
injuries are accompanied by
calpain activation and subsequent Wallerian-like degeneration. Several known inhibitors, including
leupeptin, are known to impede the activity of
calpain and associated tissue damage. We hypothesize that employment of
leupeptin in a rat model of prolonged hind limb
ischemia can mitigate muscle and nerve
injuries. Sprague-Dawley rats (n = 10) weighing between 300-400 g were employed in this study. Their left hind limbs were subjected to blood flow occlusion for a period of 2-h using a neonatal blood pressure cuff. Five rats were given twice weekly intramuscular
leupeptin injections, while the other five received saline. After 2 weeks, the animals were euthanized, their sciatic nerves and gastrocnemius muscles were harvested, fixed, stained, and analyzed using NIH Image J software. The administration of
leupeptin resulted in larger gastrocnemius muscle fiber cross-sectional areas for the right (non-
tourniquet applied) hindlimb as compared to that treated with the saline (p = 0.0110). However, no statistically significant differences were found between these two groups for the injured left hindlimb (p = 0.1440). With regards to the sciatic nerve cross-sectional areas and sciatic functional index, no differences were detected between the
leupeptin and control treated groups for both the healthy and injured hindlimbs. This research provides new insights on how to employ
leupeptin to inhibit the degenerative effects of
calpain and preserve tissues following
ischemia resulting from orthopedic or
plastic surgery procedures.