The Effect Of Pulsed Radiofrequency On Dorsal Root Ganglion Of SNI Rats On The BDNF Levels In Spinal Microglia

Objective:In this study, we aim to investigate whether the analgesic effect of PRF on DRG is related to the inhibition of BDNF-PI3K-p ERK signal pathway in the spinal cord.We investigated the analgesic mechanisms resulted from PRF on DRG and intrathecal injection of BDNF anti-body or LY294002 of rats with SNI. Adult male SD rats were subjected to SNI and then PRF therapy on dorsal root ganglion(DRG). The general behavioral, PWMT, PWTL changes were surved, the expressions of spinal cord BDNF,PI3 K and ERK protein were tested by using Western-Blot and IF.Methods:1?The effect of PRF on DRG of SNI rats on pain therholds and the BDNF levels in spinal.Rats received PRF treatment on Day 7 after SNI. The general behavioral,PWMT,PWTL changes were respectively performed on first day before SNI and 1,3,5,7,10 and14 days after SNI. On Day 14 after SNI, all rats were killed under deep anesthesia and their lumbar spinal cords were dissected to detect the levels of BDNF, PI3 K and p ERK with immunofluorescence and western blot analysis.2. Effects of intrathecal BDNF anti-body or LY294002 on pain thersholds in rat model of SNI.Under anesthesia, implantation of intrathecal cannula was executed and spared nerve injury was succeeded. The rats were received intrathecal anti-BDNF daily or LY294002 from Day 5 to Day 14 after SNI. The general behavioral,PWMT, PWTL changes were respectively performed on first day before SNI and 1,3,5,7,10 and 14 days after SNI. On Day 14 after SNI, all rats were killed under deep anesthesia and their lumbar spinal cords were dissected to detect the levels of BDNF, PI3 K and p ERK with immunofluorescence and western blot analysis.Results:1 ? The PWMT, PWTL always points were significantly decreased(P<0.05),whereas the expression of BDNF protein in spinal cords after spared nerve injury were simultaneously increased in SNI group, SNI+PRF group and SNI+Free-PRF group than those in Sham group(P<0.05). PRF on DRG on Day 7 after SNI increased PWMT and PWTL significantly compared with in SNI group and in Free-PRF group(P<0.05), but still far under Sham group(P<0.05). And the expression of BDNF protein in spinal cords were significantly decreased after PRF treatment in SNI+PRF group than in SNI group and SNI+Free-PRF group(P<0.05).2?In this study, compared with in Sham group, PWMT and PWTL were decreased in the SNI, SNI+Anti-BDNF, SNI+Saline group(P<0.05), BDNF, PI3 K and p ERK levels were simultaneously elevated in SNI group on Day 14 after SNI than those in Sham group(P<0.05). In group SNI+Anti-BDNF, it was reduced BDNF, PI3 K and p ERK than in Saline group(P<0.05), meanwhile, PWMT and PWTL was increased than SNI and Saline group(P<0.05). In group SNI+LY294002, it was reduced BDNF,PI3 K and p ERK than in DMSO group(P<0.05), meanwhile, PWMT and PWTL was increased than SNI and Saline group(P<0.05)Conclusions:1?These results indicate that activation of BDNF-PI3K-p ERK signal pathway may be highly involved in the formation and development of neuropathic pain. 2?PRF is a very useful treatment for neuropathic pain, and may be via the inhibition of BDNF-PI3K-p ERK signal pathway.