FUNCTIONAL RECOVERY FROM SCIATIC-NERVE CRUSH LESION IN THE RAT CORRELATES WITH INDIVIDUAL-DIFFERENCES IN RESPONSES TO CHRONIC INTERMITTENT STRESS

The aim of the present study was to monitor the influence of chronic s tress on functional recovery from a sciatic nerve crush lesion in the rat, Male Wistar rats underwent standard unilateral sciatic nerve crus h, Subsequently chronic stress was induced during the recovery phase u sing a daily 30 min shock box session where rats received three electr ic footshocks each session (0.5 sec, 1 mA), Reduced body weight gain, adrenal gland hypertrophy and thymus involution indicated that the str ess rats were chronically stressed, Evaluation of sensorimotor functio n revealed significant differences in recovery between control and str ess groups, Correlational analysis of individual stress rats indicated that recovery of the walking pattern was negatively correlated with a drenal gland and medulla enlargement, thymus involution, and plasma le vels of adrenocorticotrophic hormone (ACTH) and corticosterone 45 min following the final stress session, In control rats, the index of scia tic nerve function (SF index, expressed as the difference between the injured paw and the intact contralateral paw as a percentage) was sign ificantly correlated with adrenal medulla weight only, The present stu dy reveals that chronic intermittent footshock stress impedes sensorim otor recovery following a sciatic nerve crush lesion and that the cons equences of chronic intermittent stress are individually determined. W e suggest that the quality of functional locomotor recovery after nerv e crush lesion is related to the adaptive capacity or coping style of the individual rat. (C) 1997 Wiley-Liss, Inc.