Objective To prepare liposomal bupivacaine and study the local anesthetic effect by injection around sciatic nerve in rats. Methods 0.5% liposomal bupivacaine was prepared with egg yolk phosphatidylcholines,cholesterol,αtocopherol and bupivacaine using film dispersion method. Its size was calculated by light microscope and electron microscope. The encapsulation efficiency was measured by ultraviolet spectrophotometer. Forty SD rats were randomly divided into 4 goups:N1(injected with saline)、N2(injected with blank liposomes)、BP(injected with 0.5% bupivacaine)、BP-L(injected with 0.5% liposomal bupivacaine). Appearance and mechanical pain threshold were evaluated after injecting around sciatic nerve, respectively. Results The morphology of liposomal bupivacaine was like sphere,its size was 150~2 000 nm,and the encapsulation efficiency was 43.6%. No local anesthetic effect was observed in ether group N1 or N2. The duration of liposomal bupivacaine(t1,t2,t3 and ttotal) was longer than bupivacaine. Conclusion Liposomal bupivacaine can be prepared successfully with egg yolk phosphatidylcholines,cholesterol,αtocopherol and bupivacaine by using film dispersion method. The duration of sciatic nerve block by bupivacaine encapsulated in liposomes can be prolonged.
Objective To investigate the effect of curcumin on neuropathic pain in rats. Methods Thirty six male SD rats were randomly divided into 6 groups:sham operation group(Sham), solvent control group(SC),chronic constriction injury group(CCI),and curcumin treated groups(Cur30,Cur100,Cur300). Curmin30,100,300 mg•kg-1•d-1 ip.was respectively given after operation in group Cur30,Cur100,Cur300.Thermal withdrawal latency (TWL) and mechanical withdrawal threshold (MWT) of rats were measured on 1, 2 preoperative and 1, 3, 5, 7, 10, 14 postoperative days. Results TWL and MWT in CCI group were significant lower than in Sham group on every postoperative day(P<0.05,P<0.01).TWL in curcumin treated groups were higher than in CCI group on 7 postoperative day (P<0.05); TWL in group Cur100 and group Cur300 were higher than those in CCI group on 10 postoperative day (P<0.05);TWL in group Cur30 and group Cur100 were higher than in CCI group on 14 postoperative day (P<0.05);MWL in group Cur30 and group Cur100 were higher than in CCI group on 7,10,14 postoperative day (P<0.05). Conclusion Curcumin could alleviate thermal hyperalgesia and mechanical hyperalgesia induced by CCI.