ABSTRACT
Objective: To observe the effect of sea tic nerve pulsed radiofrequency (PRF) on the activation levels of microglia cells and astrocytes in spinal dorsal horn in the chronic constriction injury (CCD 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). CC1 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 CC1 operation for 120 s, with a maximum temperature of 42"C. The mechanical withdrawal thresholds (MWT) and thermal paw withdrawal latencies 0. 05). Conclusion- PRF on sciatic nerve can relieve the neuropathic pain (NT) of the CCI rat models: PRF on saatic nerve can inhibit activation of the microglia cells in the spinal dorsal horn. The analgeac mechanism of PRF on sciatic nerve may be associated with the inhibition of the activation of microglia cells in the spinal dorsal horn.
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.
ABSTRACT
Neuropathic pain is a complex state showing increased pain response with dysfunctional inhibitory neurotransmission. The TREK family, one of the two pore domain K+ (K2P) channel subgroups were focused among various mechanisms of neuropathic pain. These channels influence neuronal excitability and are thought to be related in mechano/thermosensation. However, only a little is known about the expression and role of TREK-1 and TREK-2, in neuropathic pain. It is performed to know whether TREK-1 and/or 2 are positively related in dorsal root ganglion (DRG) of a mouse neuropathic pain model, the chronic constriction injury (CCI) model. Following this purpose, Reverse Transcription Polymerase Chain Reaction (RT-PCR) and western blot analyses were performed using mouse DRG of CCI model and compared to the sham surgery group. Immunofluorescence staining of isolectin-B4 (IB4) and TREK were performed. Electrophysiological recordings of single channel currents were analyzed to obtain the information about the channel. Interactions with known TREK activators were tested to confirm the expression. While both TREK-1 and TREK-2 mRNA were significantly overexpressed in DRG of CCI mice, only TREK-1 showed significant increase (~9 fold) in western blot analysis. The TREK-1-like channel recorded in DRG neurons of the CCI mouse showed similar current-voltage relationship and conductance to TREK-1. It was easily activated by low pH solution (pH 6.3), negative pressure, and riluzole. Immunofluorescence images showed the expression of TREK-1 was stronger compared to TREK-2 on IB4 positive neurons. These results suggest that modulation of the TREK-1 channel may have beneficial analgesic effects in neuropathic pain patients.