The purpose of this study was to examine the effects of unilateral sciatic nerve injury on unaffected hindlimb muscles of rats.

Adult male Sprague-Dawley rats were assigned to one of three groups: control (C) group (n=10) that had no procedures, sham (S) group (n=10) that underwent sham left sciatic nerve transection, and sciatic nerve transection (SNT) group (n=9) that underwent left sciatic nerve transection. At 15 days rats were anesthetized, and the soleus, plantaris and gastrocnemius muscles were dissected.

Muscle weight of the unaffected plantaris muscle in the SNT group was significantly lower than in the other two groups. Type II fiber cross-sectional areas of the unaffected plantaris and gastrocnemius muscles in the SNT group were significantly smaller than in the other two groups. The decrease of muscle weights and Type I, II fiber cross-sectional areas of the unaffected three muscles in the SNT group were significantly less than that of the affected three muscles.

Hindlimb muscle atrophy occurs in the unaffected side after unilateral sciatic nerve injury, with changes in the plantaris and gastrocnemius muscle being more apparent than changes in the soleus muscle. These results have implications for nursing care, in the need to assess degree of muscle atrophy in unaffected muscles as well as affected muscles.