Gabapentin reduces mechanical allodynia in a rat model of tibial bone cancer pain / 中华行为医学与脑科学杂志

ABSTRACT

ObjectiveTo explore the effects of gabapentin on mechanical allodynia in rats with tibial bone cancer pain (BCP).MethodsForty-two female SD rats were randomized into 7 groups ( n=6)naive group (group N ),sham operation + NS control group (group SN),sham operation + GBP200mg/( kg · d) group (group SG200),BCP + NS control group (group BN),BCP + GBP50mg/( kg · d) group ( group BGS0),BCP +GBP100mg/(kg · d) group (group BG100),and BCP + GBP200mg/(kg · d) group (group BG200).The rats in group N,SN and BN received 5 ml normal saline and the rats in group SG200,BG50,BG100 and BG200 received 200,50,100 and 200 mg/( kg · d) dose of GBP via feeding from day 7 to 13 after operation,respectively.Mechanical withdrawal threshold(MWT) of the right paw and behavioral assays for ambulatory pain were measured just before operation and on days 1,3,5,7,8,10,12 and 14 after operation.ResultsMWT( (3.78 ± 0.38)g) in rats with BCP decreased and behavioral assays for ambulatory pain (0.76 ± 0.44) increased on day 7 after operation,as compared with those in group N ( ( 14.50 ± 1.38 ) g,(0.00 ± 0.00 ) ) and group sham ( ( 10.21 ± 0.88 ) g,( 0.00 ±0.00) ) (P ＜ 0.05 ).There was no apparent praxiological difference between group SN and group SG200 in a week of continuous application of gabapentin(P＞ 0.05 ).Compared with those in group BN,there was no change on MWT in group BG50 (P ＞ 0.05 ),and however,behavioral assays for ambulatory pain decreased (P ＜ 0.05 ).MWT in group BG100( (5.35 ±0.85)g) and BG200( (5.71 ±0.72) g) increased in day 10 after operation,as compared with those in group BN ( ( 2.61 ± 0.40) g) and group BG50 ( ( 3.28 ± 1.15 ) g) (P ＜ 0.05 ),and the difference was still statistically significant until day 14 (P ＜ 0.05 ).Behavioral assays for ambulatory pain in group BG100 and BG200 decreased from day 8 after operation,as compared with those in group BN and group BG50 (P ＜ 0.05 ).ConclusionGabapentin,in medium to large dosage,can inhibit pain reaction of rats with bone cancer pain.Nevertheless,with the development of cancer,the effect of gabapentin decreases.