RESUMEN
OBJECTIVE: To investigate the antinociceptive effect of intrathecal administration of HSV-I amplicon vector-mediated HPPE. METHODS: Sprague Dawley rats (290+/-30) g were randomly divided into pHSVIRES-HPPE-LacZ (SHPZ) group, pHSVIRES-LacZ (SHZ) group, and saline group (NS), and 3 d, 1 week, 2 weeks, 3 weeks, 4 weeks, and 5 weeks group,which were anesthetized with 10% chlroral hydrate 300- 350 mg/kg. A microspinal catheter was inserted into the lumbar subarachnoid space. Rats were intrathecally delivered with recombinant HSV-I amplicon vector SHPZ, SHZ or NS. The HPPE expression was detected by reverse transcription-polymerase chain reaction (RT-PCR) and radioimmune assay. Formalin 50 microL (5%) was injected into the left hindpaw, pain intensity scoring (PIS) was used to assess the antinociceptive effect. RESULTS: After in vivo transferring,neurocyte demonstrated strong positive signals with X-gal immunohistochemical staining. RT-PCR and L-enkephalin radioimmune assay found that the neural cells transferred foreign gene (HPPE) had effective expression. Intrathecal delivery of SHPZ showed antinociceptive effects on formalin induced pain for 5 weeks compared with SHZ. CONCLUSION: This amplicon virus can transfer HPPE into rat central nerve system neural cells and express efficiently, suggesting SHPZ is satisfactory treatment for gene therapy for chronic pain. Intrathecal delivery SHPZ demonstrated antinociceptive effects on formalin induced pain.