Objective To establish the replicated-deficient recombinant adenovirus-mediated thymidine kinase/acyclovir (Adtk/ACV) system and to evaluate its suicide effect on rat C6 brain gliomas in vitro and in vivo.Methods The plasmid pAdtk and pJM17 were co-infected into 293 cells (adenovector packaging cells) and the results were identified by polymerase chain reaction (PCR) assay. After the glioma C6 cells were transduced by Adtk at different multiplicity of infection (MOI) and exposed to different concentrations of ACV or gancyclovir (GCV), the cell survival curves were studied, and the cell surface was observed with scanning electronic microscopy (SEM). C6 gliomas in vivo at different inoculation days were injected with Adtk intratumorally and ACV intraperitoneally daily, and the survival duration and histologic changes of the rats were observed.Results The infectious Adtk virions had a suicide effect which was enhanced with the increase in MOIs of Adtk and ACV doses along with bystander effect. Under scanning electronic microscope, special pathologic changes were observed. ACV had a similar effect as GCV but a higher dose was used. The survival duration in day 3, day 6 and day 8 groups exceeded 90 days, and the rats in day 10 group survived 28.5±4.6 days, but the survival duration in untreated C6 group and AdLacZ/ACV (adenovirus-mediated LacZ/ACV) treated group were 16.8±3.1 and 14.0±2.2 days respectively. Conclusion Adtk/ACV system can effectively kill the rat brain gliomas in vitro and in vivo.

AIM:To study the expression of signal transduction molecules in the striatum G protein protein 4 (RGS4) and dopamine D2 receptor (D2) in conditioned place preference (CPP) rats treated with methamphetamine (meth).METHODS:METH dependence CPP model was established (1 week and 2 weeks of METH dependence groups),The protein expression of RGS4 and D2,inhibitory G protein alpha-subunit (Gαi),mitogenactivated protein kinase (MAPK) in striatum were determined by Western blotting (WB).The changes of cyclic adenosine monophosphate (cAMP) content in striatum of rats were determined by enzyme linked immunosorbent assay (ELISA).RESULTS:Compared with saline control group,the average time of rats in the methamphetamine-paired chamber for two groups was increased (P ＜ 0.05).Compared with saline control group,RGS4 protein expressions in the two METH dependent groups were reduced (P ＜0.01);compared with 1 week of METH dependence group,that of 2 weeks group was reduced significantly(P ＜ 0.05).D2,Gαi,MAPK protein and cAMP expressions in the two METH dependent groups were increased (P ＜ 0.01);compared with 1 week of METH dependence group,those of 2 weeks were increased significantly (P ＜ 0.05).CONCLUSION:RGS4 and D2 receptor signaling pathways in striatum have changed in METH dependent rats,RGS4 may be involved in the regulation of METH-dependent D2 receptor signaling pathway in METH dependent rats.