Effect of moxibustion at Shenque (CV 8) on myocardial remodeling and function in exercise-induced fatigue rats

Abstract

To explore the effect of moxibustion at Shenque (CV 8) on myocardial structure and function in exercise-induced fatigue rats. A 12-week treadmill running training was performed to create an exercise-induced fatigue rat model. Sixty eligible male specific-pathogen-free grade Sprague-Dawley rats were randomly divided into a blank group, a control group, a model group, a non-meridian non-acupoint group, a Zusanli (ST 36) group and a Shenque (CV 8) group, with 10 rats in each group. Rats in the blank group did not receive treadmill running training or moxibustion. Rats in the control group did not receive treadmill running training but received mild moxibustion at Shenque (CV 8). Rats in the model group received treadmill running training but no moxibustion. Rats in the non-meridian non-acupoint group, the Zusanli (ST 36) group and the Shenque (CV 8) group received moxibustion at the non-meridian non-acupoint points, Zusanli (ST 36) or Shenque (CV 8) immediately after each treadmill running training, 15 min each time, once a day for 5 consecutive days a week at a 2-day interval, 60 times of moxibustion in total. Left ventricular end-diastolic diameter (LVEDd), left ventricular end-systolic diameter (LVESd), left ventricular diastolic volume (LVDv), left ventricular systolic volume (LVSv), ejection fraction (EF), stroke volume (SV), early diastolic peak flow velocity of mitral valve (E) and late diastolic peak flow velocity of mitral valve (A) of each group before and after the last treadmill running training were measured. Blood was collected 6 h after the last treadmill running training, and serum C-reactive protein (CRP), myoglobin (Mb), creatine kinase-myocardial band (CK-MB), cardiac troponin I (cTnI) and cardiac troponin T (cTnT) levels were detected. Finally, the heart was separated, the heart mass (HM) was measured, the cTnT level of the myocardial tissue was detected, the ultrastructural changes of the left ventricular myocardium were observed by transmission electron microscope, the left ventricular fraction shortening (LVFS), E/A and heart mass index (HMI) were calculated. Compared with the same group before treatment, the rat cardiac LVEDd, LVESd, LVDv, LVSv, SV, E and A were significantly increased (all P<0.01), and the rat LVFS, E/A and EF were significantly decreased (all P<0.01) in the model group and the non-meridian non-acupoint group after treatment; the rat cardiac SV, LVDv, LVSv, E and A were all increased (all P<0.01), while E/A and EF were decreased (all P<0.01) in the Zusanli (ST 36) group after treatment; the rat cardiac LVDv, E and A were significantly increased (P<0.01 or P<0.05), and E/A was significantly decreased (P<0.01) in the Shenque (CV 8) group after treatment. After treatment, compared with the blank group, the rat cardiac LVEDd, LVESd, SV, LVDv, LVSv, E, A, the serum CRP, Mb, CK-MB, cTnI, cTnT and HMI, and the myocardial cTnT were increased (all P<0.01), and the LVFS, E/A and EF were all reduced (all P<0.01) in the model group; compared with the model group and the non-meridian non-acupoint group, rats in the Zusanli (ST 36) group and the Shenque (CV 8) group showed decreased LVEDd, LVESd, SV, LVDv, LVSv, E, A, serum CRP, Mb, CK-MB, cTnI, cTnT and HMI, and myocardial cTnT (P<0.01 or P<0.05), along with increased LVFS, E/A and EF (all P<0.01); compared with the Zusanli (ST 36) group, Mb and A of the Shenque (CV 8) group were decreased (both P<0.01), while both E/A and EF were increased (P<0.01, P<0.05). Transmission electron microscopy examination showed that myofibrils in the blank group and the control group were neatly arranged with clear light and dark bands; the model group and the non-meridian non-acupoint group showed different degrees of myofibril disintegration and breakage, increased and aggregated mitochondria of different sizes, and increased electron density. The myofibrils in the Shenque (CV 8) group and Zusanli (ST 36) group were arranged neatly with clear light and dark bands, and compensatory hyperplasia of mitochondria. Moxibustion at Shenque (CV 8) and Zusanli (ST 36) both can effectively improve the occurrence of myocardial remodeling in exercise-induced fatigue rats, and the effect of moxibustion at Shenque (CV 8) is better in improving cardiac function.