The protective effect of exogenic nerve growth factor by intrathecal injection on lidocaine-induced neurotoxicity in rats

Abstract

Objective To investigate the protective effect of exogenic nerve growth factor (NGF) on lidocaine-induced neurotoxicity in rats.Methods After successful intrathecal catherization and positive lidocaine test,60 rats were randomly allocated into NS group (S group) and NGF groups (N group) which included P0,P1 and P8 subgroups with 10 in each subgroups.Two P0 subgroups:sham operation; Two P1 subgroups:20％ lidocaine 20 μl intrathecal injection.Two P8 subgroups:20％ lidocaine 20 μl intrathecal injection and NS/NGF 20 μl intrathecal injection on consecutive 7 d.TFL and MF on consecutive 7 din two P8 subgroups and the pathologic changes in the spinal cord by method of microscopy and electron scope were observed by a blind investigator in each subgroups.Results Compared with S group P8 subgroup,maximal effect proportion (MEP) of TFL [(62.5± 20.3)％ vs (32.6±23.5)％,(51.9±23.7) ％ vs (25.8±26.3)％,(43.8±22.5)％ vs (20.5±24.3)％,(38.4±25.7)％ vs (18.5±23.7)％] (P＜0.05) and MF 3 vs 0,3 vs 0,3 vs 0,3 vs 0 (P＜0.05) were significantly decreased at the timing of 5 d-7 d.Edema vacuolar degeneration and interstitial edema in white matter of posterior horn of spinal cord were found in P8 subgroup of group S.On transmission electroscope,typical changes included interstitial edema,loosening of the laminae of myelinated fibers,axon swelling and local degeneration with most serious injury in P8 subgroup of group S,however,the above is improved in P8 subgroup of group S.Conclusions Exogenic NGF may repair the cells undergoing apoptosis therefore decrease the injury probably. Key words: Lidocaine; Spinal cord; Neurotoxicity; Nerve growth factor