The Role Of HCN4 Channel Expression In The Spinal Dorsal Horn Of Rats With Paclitaxel-induced Neuropathic Pain And Its Relationship With GABA_B Receptor

Objective:Paclitaxel,as a clinical antitumor drug,has been widely used in antitumor treatment of breast,ovarian and lung cancer patients,but it has shown dose-dependent neurotoxicity during clinical use,that is paclitaxel-induced peripheral neuropathic pain,it has plagued the medical community,and there is still a lack of effective treatments in clinical practice.Elucidating its pathogenesis is of great clinical significance for finding effective treatments.In this experiment,a paclitaxel-induced neuralgia model in rats was prepared by intraperitoneal injection of paclitaxel.Intrathecal injections of HCN4 channel lentivirus and HCN channel inhibitor ZD7288 were performed to investigate the expression of HCN4 channel in the spinal dorsal horn of rats with paclitaxel-induced neuropathic pain and its relationship with GABA_Breceptor.Methods:The male SD rats of clean grade aged 6?9 weeks,weighing 180?220 g were purchased from the animal experiment center of hebei medical university.The model of paclitaxel-induced neuropathic pain was established by intraperitoneal injection of 2 mg/kg of paclitaxel1,3,5 and 7 days after the experiment.After successful intrathecal catheterization,the rats were randomly divided into 5 groups?n=10?:Paclitaxel model group?P group?,paclitaxel model+saline?N?,paclitaxel model+lentivirus empty vector group?BV group?,paclitaxel model+HCN4 channel lentivirus group?H group?,paclitaxel model+ZD7288 group?I group?,10 rats of the same age as the blank control group?C group?.On the 15th day after intraperitoneal injection,different drugs were intrathecally injected with 20?L:Group N was injected with normal saline,group BV was injected with HCN4 channel lentivirus empty vector?1 X10⁸ TU/ml?,and group H was injected with HCN4channel lentivirus?1 X10⁸ TU/ml?;On the 21th day after intraperitoneal injection:group I was injected with HCN channel inhibitor ZD7288?30?g/20?L?.The 50%mechanical foot shrinkage threshold?MWT?was measured 1 day before intraperitoneal injection?T₀?,14 days?T₁?and21 days?T₂?after injection.The expression of HCN4 channel and GABA_B receptor in the spinal dorsal horn was determined by immunohistochemistry and Western blot 21 days?T₂?after intraperitoneal injection.Results:1.Behavioral results:Compared with the T₀,MWT decreased in group P,N,BV,H and group I at T₁?P<0.05?;Compared with the T₁,MWT increased in group H and group I at T₂?P<0.05?.Compared with group C,MWT decreased in group P,group N,group BV,group H and group I at T₁?P<0.05?;compared with group P,MWT0.05);2.Immunohistochemistry results:Compared with group C,the integrated optical density of HCN4 channel protein increased and GABA_B receptor protein decreased in the spinal dorsal horn of group P at T₂?P<0.05?;compared with group P,the integrated optical density of HCN4 channel protein decreased and GABA_B receptor protein increased0.05);3.Western blot results:Compared with group C,the expression of HCN4 channel protein increased and GABA_B receptor protein decreased in the spinal dorsal horn of group P at T2?P<0.05?;compared with group P,the expression of HCN4 channel protein decreased and GABA_Breceptor protein increased in the spinal dorsal horn of group H and group I at T2?P<0.05?.Conclusion:1.Paclitaxel can induce neuropathic pain by up-regulating the expression of HCN4 channel protein in the spinal dorsal horn of rat.2.The role of GABA_B receptor protein in paclitaxel-induced neuropathic pain may be related to up regulation of HCN4 channels.