Combined Antiallodynic Effect Of Neurotropin And Gabapentin In Rats With L5-spinal Nerve Ligation

Part I the analgesic effect of Neurotropin and gabapentin in rats with L5-spinal nerve ligationObjective:Use rats with L5-spinal nerve ligation (SNL) model to induce classic neuropathic pain,observe the analgesic effect and the characteristics of Neurotropin and gabapentin.Methods:The normal adult male SD rats were randomly divided into spinal nerve ligation group (SNL group) and sham operation group (Sham group).SNL group rats were produced L5-spinal nerve ligation according to the method of Kim and Chung, Sham group rats made the same operation with SNL group, but without ligation and cut off after setting of lines on the L5spinal nerve. Application of von-Frey filament fiber to measure the paw withdraw mechanical threshold (PWMT).14days after spinal nerve ligation rats were randomly divided into seven groups(n=5):different concentrations of neurotropin group (N1group50Nu/kg, N2group100Nu/kg, N3group200Nu/kg); different concentrations of gabapentin group (G1Group25mg/kg, G2group50mg/kg, G3group100mg/kg); control group (C group). The different concentrations Neurotropin and gabapentin with SNL rats were practiced gavage treatment,10ml/kg saline gavage as a control group. Of Neurotropin rats were fed before,30min,60min,90min and120min after administration,applicationed von-Frey filament fibers to measure the PWMT; gabapentin group and control group rats were fed before and30min,60min,90min,120min,150min,180min,210min and240min after administration.applicationed von Frey filament fibers to measure the PWMT. And to observe the changes of the mechanical pain threshold in rats.Results:Compare the different concentrations Neurotropin rats with C group after gavage30min,60min and90min,the difference on PWMT was statistically significant,P<0.05; Compare to the N1, N2and N3rats were fed after30min,60min and90min, the difference on PWMT was statistically significant,P<0.05; and the PWMT in N1, N2and N3rats reached a peak after gavage60min, reached the highest value (6.7±1.3g,8.4±1.2g,10.0±0.9g); different concentrations of gabapentin rats after gavage90min,120min,150min,180min and210min,the PWMT compare to the Group C at the same time point,P<0.05, the difference was statistically significant; G1, G2and G3rats after gavage90min,120min,150min,180min and210min,the PWMT comparison, P<0.05, the difference was statistically significant;after gavage120min, PWMT of G1, G2and G3groups of rats got the highest value (5.8±0.7g,8.2±0.8g,11.4±0.7g).Conclusion:Neurotropin and gabapentin can make the PWMT of L5-SNL rats increase the pain threshold, and a dose-dependent; Neurotropin rapid onset, short duration; gabapentin slowly onset, maintain a longer time.PartⅡ Combined antiallodynic effect of Neurotropin and gabapentin in rats with L5-spinal nerve ligationObjective:To study the combined antiallodynic effect of Neurotropin and gabapentin for L5-SNL model in rats.Methods:SNL14days after the rats were randomly divided into four groups(n=10):N50group (Neurotropin135Nu/kg),G50group (gabapentin45mg/kg), the NG50(Neurotropin135Nu/kg+gabapentin45mg/kg),and the control group (saline10ml/kg), respectively rats were gavage treatment, before gavage and after administration30min,60min,90min,120min,150min,180min,210,240min and270min application of von Frey filament fibers to measure the PWMT of the rats left hind leg.Results:NG50group and C group after gavage30min,60min,90min,120min,150min,180min,210min,240min,the PWMT values comparison, P<0.05, there are significant difference; NG50groups after gavage60min and120min,compare to the PWMT value of the N50group after60min, and the G50group after120min,P<0.05, the difference was statistically significant; NG50in60min and120min PWMT were of value highest,11.3±0.9g and10.9±1.0g. Conclusion:The pain threshold in combination Neurotropin and gabapentin of SNL rats increase, and have two peak times, onset faster compared with gabapentin, maintain longer than Neurotropin. Therefore the combination of Neurotropin and gabapentin to treat neuropathic pain is feasible.