Study On The Mechanism Of BDNF/TrkB Signaling Regulating Synaptic Efficacy And Mitochondrial Function In Bone Cancer Pai

Objective In the advanced stage of cancer,bone metastasis of cancer cells can occur,leading to the destruction of bone structure and seriously affecting the quality of life of patients.Research has shown that the BDNF/Trk B pathway regulates the transmission of pain signals and plays an important role in the occurrence and development of pain.This study focuses on the BDNF/Trk B signal in the dorsal horn of the spinal cord,using a rat model of bone cancer pain as the research object.By analyzing the changes in downstream signals and synaptic related protein expression levels that regulate the activity of this signal,the mechanism of BDNF/Trk B signal regulation of pain transmission is explored,providing research ideas and potential targets for the treatment of cancer pain.Methods Male SD rats were injected with breast cancer cell MRMT-1 into the tibia to establish a bone cancer pain model.The success of the model was verified by X-ray imaging,HE staining morphology of bone slices and pain behavior detection of rats in each group.After successfully establishing the model,the effects of intrathecal administration of Trk B receptor antagonist ANA-12 and PI3 K inhibitor LY294002 on pain perception behavior in rats with bone cancer pain were recorded;Morphological analysis of spinal dorsal horn neuron activity and inflammatory levels;Observation of changes in the morphology and quantity of mitochondria and synaptic vesicles in the spinal cord using transmission electron microscopy;Immunoblotting and immunofluorescence were used to detect the expression levels of BDNF/Trk B,downstream signaling related proteins,mitochondria,and synaptic proteins in the spinal cord tissue of rats in each group;Cellular level analysis of the protective effects of ANA-12 and LY294002 treatments on inflammation induced mitochondrial damage.Results(1)Successfully constructed a BCP rat model: behavioral tests showed an increase in pain sensitivity in rats,X-ray showed tibial bone tissue damage,HE staining showed trabecular bone loss,and bone structure destruction;(2)The activity of glial cells in the spinal cord of BCP rats increases,the expression of inflammatory factors increases,and the infiltration of inflammation increases;(3)BDNF/Trk B and downstream signaling pathways Akt/GSK-3 in the spinal cord of BCP rats β Increased activity,intrathecal injection of ANA-12 and LY294002 inhibits BDNF/Trk B and Akt/GSK-3 β Signal activity;(4)Inhibiting BDNF/Trk B and downstream signals downregulating pain sensitivity of BCP animals and enhancing their motor ability to alleviate bone cancer pain;(5)Transmission electron microscopy observation showed an increase in vesicles in the presynaptic activated area of BCP rats,and Nissl staining results showed a decrease in the number of neurons,indicating a decrease in synaptic efficacy in BCP rats;(6)The expression levels of synaptic related proteins,mitochondrial related proteins,and calcium signaling related proteins in BCP rats are abnormal.Inhibiting BDNF/Trk B and downstream signals can restore the expression levels of these proteins and balance excitatory inhibitory synaptic signals;(7)Cellular level validation of ANA-12 and LY294002 inhibiting inflammation induced mitochondrial functional damage: ANA-12 and LY294002 upregulate IL-1 β The mitochondrial membrane potential is reduced and IL-1 is down regulated β Induced increase in mitochondrial ROS levels.Conclusion Inhibiting the BDNF/Trk B signaling pathway can regulate synaptic efficacy,restore mitochondrial function,and alleviate pain perception behavior in bone cancer pain rats.