| Objective: Spinal cord ischemia/reperfusion injury(Spinal cord ischemia-reperfusion injury,SCII)is a common,unpredictable,and serious complication in thoracic and abdominal aortic surgery.SCII can induce a series of secondary events,such as neuronal or microglial damage,as well as further motor and sensory impairment.Studies have shown that these injuries are closely related to inflammatory response.Nmb(neuromedin B)is a neuropeptide belonging to the cinobufagin family.It was originally extracted from porcine stomach and spinal cord tissues.After binding to the receptor,Nmb can perform a variety of physiological functions,including regulating food intake,smooth muscle contraction,body temperature,and stress response.T-type calcium channels belong to the Cav3 family of low-voltage activated T-type channels(low voltage-activated channels,LVT).There are three subtypes of α1 subunits of T-type calcium channels: Cav3.1,Cav3.2and Cav3.3.Cav3.2 is specifically expressed in brain and peripheral organs and plays different pharmacological characteristics.Some studies have found that the activation of Cav3.2 can significantly increase the expression of IL-1 in the rat model of cerebral ischemia-reperfusion.Mi RNAs is a kind of non-coding single-stranded RNA with a length of about 22 nucleotides.It inhibits the translation of m RNA or promotes its degradation by interacting with the 3’ untranslated region(UTR)of the target gene.It has been confirmed that many miRNAs are involved in the process of central nervous system(CNS)injury.In the rat spinal cord nerve ligation(SNL)model,miR-214-3p inhibits astrocyte colony-stimulating factor and participates in neuropathic pain after nerve injury.Since the relationship between miR-214-3p and Nmb has not been studied,in this study,I further understand the mechanism of SCII and provide new ideas for the development of new therapeutic strategies by studying the relationship between Nmb,Cav3.2,IL-1,and miRNAs.Methods: The SCII model was established by clamping the abdominal aorta of SD male rats for 60 minutes.The targeted binding relationship between miR-214-3p and Nmb was detected by the double luciferase reporter gene.Intrathecal injection of miR-214-3p atomic,miR-214-3p antagomir,PD168368(Nmb R inhibitor)and Cav3.2-si RNA were used to verify the regulatory relationship between miR-214-3p and Nmb/Cav3.2 and its effect on SCII damage in rats.The protein expression levels of Nmb,Cav3.2,and IL-1β were detected by Western blotting(WB),and the behavior of rats was tested by Tarlov score.The cellular localization of Nmb and Cav3.2 was quantitatively detected by immunofluorescence staining,the expression of Nmb and Cav3.2 in Sham group and IR group was analyzed,and the cell type was determined by cell specific markers.Results: Compared with the sham group,the protein expression levels of Nmb,Cav3.2,and IL-1β in the IR-24 h group were significantly increased.Compared with IR group,intrathecal injection of PD168368 significantly inhibited the expression of Cav3.2 and inflammatory factor IL-1β,while intrathecal injection of Cav3.2-si RNA decreased the expression of IL-1 β.Overexpression of miR-214-3p decreased the expression of IL-1 β and improved the motor function of lower limbs in rats with IR,while inhibiting the expression of miR-214-3p could reverse these effectsConclusions: In the rat model of SCII,the expression of Nmb increased and Cav3.2 was activated 24 hours after spinal cord injury,which led to abnormal excitation of motoneurons in the anterior horn of the spinal cord and increased release of IL-1β.Increasing the level of miR-214-3p could improve this effect. |
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