The Application Of Drug Combination For Pain Treatment- Basic And Clinical Research On The Analgesic Effect Of Morphine And Buprenorphine Combination And The Underlying Mechanisms

Part ⅠObservation about analgesic effect of different doses’Buprenorphine combination with morphine for rat model of bone cancer pain and expression of MOR,KOR and DOR in rat’s Periaqueductal Gray, LC and Lumbosacral spina cordAim to investigate the therapeutic effects of different doses of buprenorphine combined with morphine on bone cancer pain in a rat model and evaluatetheexpression of opioid receptors in the central nervous system. Methods Female adult wistar rats were selected for this experiment.After Walker256 rat breast cancer cells were subcutaneously injected into the left tibia of the rats to induce bone cancer pain, the model rats were divided into 8 groups(n=8 for each):M group(morphine 10mg/kg),MB1 group(morphine10mg/kg+ buprenorphine 20ug/kg), MB2 group(morphine10mg/kg+buprenorphine 40ug/kg), MB3 group(morphine10mg/kg+buprenorphine 60ug/kg),BB1 group (buprenorphine50ug/kg +buprenorphine 20ug/kg), BB2 group (buprenorphine50ug/kg+buprenorphine40ug/kg), BB3 group (buprenorphine50ug/kg+buprenorphine 60ug/kg), Control group (isotonic saline 1ml). Morphine and/or buprenorphine were subcutaneously given twice a day (at 7:30am and 7:30 pm, respectively) for 8 consecutive days. From day 1 of injection, all rats underwent behavioral pain tests (tail flick test) after 7:00 pm. To charify the mechanisms underlying these distinct analgesic profiles,western-blot analysis examined the expression of opioid receptors’protein levels in central nerve system.Results The results showed that tail-flick latencyof MB1 and MB2 group is longer than morphine and control group, and the difference is significant(D7&D8, MB1&MB2VS.M group, P<0.001).Furthermoredownregulated of MOR protein, downregulated of DOR protein in PG,upregulated of MOR’s.KOR’s and DOR’s protein in LC and Lumbosacral spina cord of group M. The proteins of MOR were both upregualted in PAG of group MB1 MB2. The protein of KORwere both downregulated of in PAG and lumbosarcral spinal cord of group MB1 compared with thosein the M group (MB1 VS. M group, P<0.001).Conclusion:we found that systemic administration of lower dose buprenorphine could prevent morphine tolerance and would decrease the analgesic effect of morphine. Changes of opioid receptors in PAG and lumbar spinal cord may be one of the mechanisms.Part ⅡObservation about analgesic effect of different doses’Buprenorphine combination with morphine for rat model of bone cancer pain and expression of MOR and apoptosis in rat’s Periaqueductal Gray and Dorsal horn of lumbar spinal cordBackground:Cancer pain is common in patients with cancer. Morphine is the best choice, but tolerance can appear.Aim:To investigate the effects of different doses of buprenorphine combined with morphine in a rat model of bone cancer pain and expression of MOR and apoptosis in rat’s Periaqueductal Gray and Dorsal horn of lumbar spinal cord..Methods:Female adult Wistar rats were divided into eight groups(n=8/group):morphine 10mg/kg (M),morphine10mg/kg+buprenorphine 20 μg/kg (MB1), buprenorphine 20 μg/kg (B1), morphine 10mg/kg+buprenorphine 60 μg/kg (MB2), buprenorphine 60 μg/kg (B2), control(saline, 1ml), sham (surgery without cancer cells), and blank (no intervention).Models were achieved by cancer cell injection into the tibia. The tail flick latency(TFL) and paw withdrawal tests (PWT) were recorded and calculated the %MPE to assess pain. RT-PCR and western-blot analysis examined the expression of MOR’s mRNA and protein levels in PAG and DH. Apoptosis was evaluated by the TUNEL method. Results:MPE% of TFL and PWT in M group began to decrease significantly on Day 6 and Day 5 respectively(P<0.05), to reach a level similar to the control groups by day 8 and day 7 respectively (P>0.05).In the Day 7 and Day 8, MPE% of TFL and PWT in MB1 group were higher than the rest of groups and was statistically significant(P<0.001). The expression of mRNA and protein of MOR of MB1 group were higher than M group both in periaqueductal gray (PAG) and dorsal horn of lumbar spinal cord(DH). The percentage of apoptosis of neurons and glial cells apoptosis in MB1 group was lower than M, B2, MB2 group significantly in the periaqueductal gray and dorsal horn of lumbar spinal cord (P<0.001). Conclusion:Administration of lower dose of buprenorphine attenuated apoptosis via MOR in the periaqueductal gray and dorsal horn of lumbar spinal cord, which might be related to lower morphine tolerance.Part ⅢEfficacy of combination of morphine sulfate controlled-release tablet and buprenorphine sublingual tablet in moderate to severe cancer pain patientObjective To investigate the efficacy of combination of morphine sulfate controlled-release tablet and buprenorphine sublingual tablet in patients with moderate to severe cancer pain, and explore effective analgesic therapies for advanced cancer pain patients. Methods One hundred and fifty patients with advanced cancer pain whose visual analog scale (VAS) scores were greater than 3 points and VAS scores were still greater than 3 points after treated with controlled-release tablet of morphine alone were randomly divided into two groups (n=75):controlled-release morphine tablet alone group (M group) and conbination use of controlled-release morphine tablet with buprenorphine tablet group (MB group). Analgesic effect, adverse reactions, living quality and patient’s satisfaction were compared. Results Compared with single usage of controlled-release tablet of morphine, the analgesic effect of combined therapy was significant, VAS score was significantly reduced(M group/MB group:M 26/10, S 4/0 P<0.05). Nausea, vomiting and other adverse reactions decreased significantly(M group/MB group:nausea and vomiting 12/2, drowsiness 4/2, respiratory depression 9/4, dysuria 8/3,constipation 8/4 P<0.05). Patient’s satisfaction(M group/MB group:very satisfaction 10/14, satisfaction 36/47, P<0.05) and living quality were significantly improved(M group/MB group:sleep(5.5±1.2)/(4.6±0.7), Mood(5.4±0.5)/(4.6±1.2), Daily activities(5.1±0.4)/(4.9±0.5) Social activities(5.5±0.4))/(4.8±1.6) P<0.05). Conclusions The joint application of morphine sulfate controlled-release tablet and buprenorphine sublingual tablet was effective for advanced cancer pain. It can improve the potency of analgesia, reduce the incidence of adverse effects and improve the living quality of patients.