Effect of sciatic nerve pulsed radiofrequency glial activation levels in spinal dorsal horn in chronic constriction injury rat models and its analgesia effect / 吉林大学学报(医学版)

ABSTRACT

Objective:To observe the effect of sciatic nerve pulsed radiofrequency (PRF) on the activation levels of microglia cells and astrocytes in spinal dorsal horn in the chronic constriction injury (CCI) rat models, and to explore the relationships between the analgesic mechanism of sciatic nerve PRF and the activation levels of microglia cells and astrocytes in the spinal dorsal horn.Methods:Forty male SD rats were randomly divided into CCI shamoperation+RPF sham group (SS group) , CCI sham-operation+RPF group (SP group) , CCI+RPF sham group (CS group) , CCI+RPF group (CP group) (n=10) .PRF was applied on the sciatic nerve on the 4th day after CCI operation for 120s, with a maximum temperature of 42℃.The mechanical withdrawal thresholds (MWT) and thermal paw withdrawal latencies (TWL) were measured to evaluate mechanical hyperalgesia and thermal hyperalgesia 1dbefore operation (D0) and 1, 3, 5, 7dafter operation (D1, D3, D5, D7) .Western blotting method was used to detect the protein expression levels of ionized calcium binding adapter molecule 1 (Iba-1) and glial fibrillary acidic protein (GFAP) in the ipsilateral spinal dorsal horn of L3-5after pain behavioral test (D7) .Results:Compared with SS group, the rats in CS group after CCI had the significant behavioral changes, such as hallux valgus, lameness, toe bending, and foot raising during walking;MWT and TWL were decreased significantly (P＜0.01) ;the expression levels of Iba-1and GFAP proteins in the ipsilateral spinal dorsal horn were increased significantly (P＜0.05) .Compared with CS group, the behavioral changes of the rats in CP group (D5, D7) such as hallux valgus, lameness, toe bending, and foot raising during walking were alleviated significantly;MWT and TWL were increased significantly (P＜0.01) ;the Iba-1protein expression level in spinal dorsal horn was downregulated significantly (P＜0.05) and the GFAP protein expression level did not change significantly (P＞0.05) .Conclusion:PRF on sciatic nerve can relieve the neuropathic pain (NP) of the CCI rat models;PRF on sciatic nerve can inhibit activation of the microglia cells in the spinal dorsal horn.The analgesic mechanism of PRF on sciatic nerve may be associated with the inhibition of the activation of microglia cells in the spinal dorsal horn.