Effect of intrathecal injection of magnesium sulfate on pain behavior in bone cancer pain mouse / 中华行为医学与脑科学杂志

ABSTRACT

ObjectiveTo investigate the effect of intrathecal injection of magnesium sulfate ( MgSO4 ) on pain behavior in mouse with bone cancer pain.Methods56 male 8-10 week old C3H/HeJ mice weighing 18-22 g were divided randomly into 7 groups ( n =8 ):sham group (S group),control group (C group) and MgSO4 plus morphine treat groups( T1-T5 group).Croup C and T mice were induced bone cancer pain models by intra-rightfemur inoculation of osteolytic NCTC2472 cells while group S were injected of only α-MEM.On the 14d after inoculation,group S and C received intrathecal injection of artificial cerebrospinal fluid 5 μl,while group T1-T5 received intrathecal injection of MgSO4 14.4 μg,43.2 μg,86.4 μg,morphine 0.36 μg,MgSO4 14.4 μg-morphine 0.36 μg,which were dissolved in 5 μl artificial cerebrospinal fluid.Micc received pain behavior tests including quantification of spontaneous flinches,paw withdrawal mechanical threshold (PWMT) and paw withdrawal thermal latency (PWTL) at 0.5h before and 0.5h,2h,4h,gh after administration.ResultsTreatment with MgSO4 (14.4 μg),morphine (0.36 μg) have no effect on bone cancer pain,while treatment with MgSO4 (43.2 μg,86.4 μg)can dose-dependently reverse quantification of spontaneous flinches,mechanical allodynia and thermal hypcralgesia which were induced by inoculation as well as MgSO4 14.4 μg-morphine 0.36 μg.At 0.5 h after administration,the quantification of spontancous flinches of the three groups( ( 10.08 ± 1.66),(7.35 ± 1.36),( 10.54 ± 1.32 ) ) were decrcased when compared with control group ( 13.05 ± 2.06 ),PWMT ( (0.81 ± 0.22 ) g; ( 1.33 ± 0.19)g; (0.93 ±0.26)g),PWTL( (10.57 ±1.53)s; (13.12 ±1.71)s; (11.46 ±1.83)s) were increased when compared with control group ( (0.42 ± 0.23 ) g,( 8.87 ± 1.27 ) s) (P ＜ 0.05 ).The effect reached maximum level at 2h,lasted for at least 4h and disappeared at 8h.ConclusionIntrathecal injection MgSO4 can effectively attenuate bone cancer pain dose-dependently.At the same time MgSO4 can amplify the analgesic effect of subliminal morphine.