Effects Of Electroacupuncture On Expression Of P2X₃/TRPV₁/SP Nociceptors At Xinshu Acupoint Of Acute Myocardial Ischemia Rats

ObjectiveObserve the effects of electroacupuncture（EA）at Xinshu（BL15）on cardiac function and expression of P2X₃/TRPV₁/SP nociceptors at left Xinshu acupoint of acute myocardial ischemia rats.To investigate the relationship of EA mechanism with acupoint response based on P2X₃/TRPV₁/SP nociceptors.Methods1.Grouping and modeling:24 SD rats were randomly divided into the control group,the model group and the EA group,with 8 rats per group.Acute myocardial ischemia model was prepared by subcutaneous injection of 60 mg/kg isoproterenol hydrochloride twice with an interval of 48 h in the model and EA groups.And the control group was injected with normal saline subcutaneously.2.Intervention:After modeling,rats in the EA group were intervened with EA at bilateral Xinshu（BL15）for 30 minutes,once a day for 3 days.The negative pole of the needle is connected to the BL15,while the positive pole is connected to the homolateral caudal root（intermittent wave,15 Hz,1～2 m A）.The control and model group were only grasped and fixed without EA.3.Indicator observation:ST segment deviation and T Amplitude of ECG（electrocardiogram）was recorded in each group of rats.HE staining was used to observe the myocardial structure.The protein and gene contents of P2X₃,TRPV₁,SP at left Xinshu acupoint were detected by Western-blot and RT q PCR（Real-time Quantitative PCR Detection System）.Results1.ECG analysis:a.After modeling,the ST deviation of 16 modeling rats increased（P<0.01）,and the T amplitude voltage of modeling rats decreased（P<0.01）.b.After intervention,compared with the control group,the ST deviation of model group rats decreased（P<0.01）;compared with the model group,the abnormal ST deviation in the ECG got rectified after3days EA treatment（P<0.05）.2.HE staining to observe myocardial tissue structure:the control group myocardial cells were neatly arranged and the edges were clear;The model group showed edematous myocardial cells,loose cytoplasm,blurred cell boundaries,disordered muscle fiber,and inflammatory cell infiltration in the intercellular substance.Compared with the model group,the EA group had obvious improvement in muscle fiber disorders,and reduced inflammatory cell infiltration.3.P2X₃,TRPV₁and SP receptor m RNA expression:compared with the control group,the m RNA expression of P2X₃,TRPV₁and SP in the model group increased（P<0.05）;compared with the model group,the m RNA expression of P2X₃and TRPV₁decreased in the EA group（P<0.01）,the m RNA expression of SP decreased in the EA group,but there was no significant difference（P>0.05）.4.P2X₃,TRPV₁and SP receptor protein expression:Compared with the control group,the protein expression of P2X₃,TRPV₁and SP in the model group increased（P<0.01）;compared with the model group,the protein expression of P2X₃,TRPV₁and SP in the EA group decreased（P<0.05）.Conclusions1.Electroacupuncture can improve the cardiac function of rats with acute myocardial ischemia.2.Acute myocardial ischemia can activate P2X₃/TRPV₁/SP nociceptors at BL15 acupoint.The improvement of myocardial ischemia by EA in rats is related to the inhibition of these nociceptors.P2X₃/TRPV₁/SP nociceptors may be the important substances for transmitting electroacupuncture stimulation signals.