| Objective: To explore the expressions of C-fos and Reg-Ⅲβ in thedorsal root of rats with neuropathic pain mediated by dorsal root reflex,and to investigate the effect of nimodipine treatment on them.Methods: After the establishment of dorsal root reflex-mediatedneuropathic pain by selective spared nerve injury (SNI) in SD rats, VonFrey filament measurement and real-time fluorescence quantitativepolymerase chain reaction (RT-qPCR) were performed to determine themechanical pain threshold of rats’ hind limbs and the endogenousmRNA expressions of C-fos and Reg-Ⅲ β in the dorsal root at differenttime points, respectively. Nimodipine was given at gradient doses in theexperimental rats to examine its effect on the molecular expressions.Results: Compared with the unchanged mRNA expressions of C-fos andReg-Ⅲ β in rats from shamed-surgery group, they uniformly increased inrats from SNI groups, among which C-fos mRNA peaked at3days aftersurgery (8.92-fold, P <0.01), and Reg-Ⅲ β mRNA peaked at5days aftersurgery (7.96-fold, P <0.01). After intraperitoneal injection ofnimodipine, the increasing tendencies of both C-fos and Reg-Ⅲβ expression were substantially inhibited in a time-and dose-dependentmanner. Similar antagonistic effect of nimodipine treatment with regardto mechanical pain threshold was also determined in a dose-dependentmanner, which progressively decreased in the SNI model rats as early as1day after surgery compared to the basal level (23.34±1.34vs.48.30±0.93, P<0.001). It continued till5days after surgery and followedby a slow recovery. On day5after surgery, nimodipine treatmentresulted in a significant inhibition on the decline of pain threshold(17.50±0.89vs.5.76±0.91, P<0.001)Conclusion: Selective SNI substantially induces mRNA expressionsof C-fos and Reg-Ⅲβ in the dorsal root of rats. Nimodipine treatmentcan significantly alleviate the neuropathic pain and reduce its duration,which may be potentially related to the reversal of c-fos and Reg-Ⅲβexpressions. |
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