Influence of nerve growth factor in neuropeptides and nerve conduction velocity in rats with experimental diabetic peripheral neuropathy

Objective To investigate the influence of nerve growth factor (NGF) in neuropeptides and nerve conduction velocity in rats with experimental diabetic peripheral neuropathy (DNP).Methods Thirty-five 6-week-old male Wistar rats,weighing 175-215 g,were chosen in our study and randomly divided into healthy control group (n=10),DNP model group (n=13) and NGF treatment group (n=12).Rats in the latter 2 group were induced with the interference of administered streptozotocin,and rats in the NGF treatment group were treated with NGF (40 μg/kg).The immunopositive cells percentages of substance P (SP) and calcitonin gene-related peptide (CGRP) in dorsal root ganglion (DRG) were observed and measured; the motor nerve conduction velocity (MNCV) and sensory nerve conduction velocity (SNCV) were measured and compared among the three groups.Results As compared with those in the healthy control group,the immunopositive cells percentages of SP (27.710％±3.471％ vs 44.225％±8.213％) and CGRP (36.360％±12.027％ vs 47.400％±13.723％) in the DRG of DNP model group were significantly decreased (P＜0.05); as compared with those in the healthy control group,the MNCV[(35.80±6.19) m/s vs (55.83±10.30) m/s] and SNCV[(39.62±6.69) m/s vs (47.02 ±7.52) m/s)] of DNP model group were significantly decreased (P＜0.05); however,obvious increase of SP (49.417％±6.753％) and CGRP (53.811％±7.125％),MNCV (41.80±3.45) m/s and SNCV (42.92±6.69 m/s) in the NGF treatment group was noted as compared with those in the DNP model group (P＜0.05).Conclusion The nerve conduction velocity and NGF related neuropeptides (SP and CGRP) decrease in rats with DNP; treatment with NGF promotes the expression ofneuropeptides and increases the nerve conduction velocity. Key words: Diabetic neuropathy;  Nerve growth factor;  Neuropeptide;  Nerve conduction velocity