Protective effects of berberine against exhaustion exercise induced myocardial injury in rats / 中华心血管病杂志

Objective@#To investigate the effect and possible mechanism of berberine (Ber) on myocardial injury induced by exhaustion exercise (Ee).@*Methods@#Forty healthy male SPF Sprague-Dawley rats were randomly divided into 5 groups using the random unit group design method: control group, Ee group and Ee plus Ber group (low: 50 mg·kg-1·d-1, medium: 100 mg·kg-1·d-1 and high dose: 150 mg·kg-1·d-1, n=8 each). Ber (1.5 ml) or equal volume saline was given per gavage for 14 days. Rats assigned to Ee groups underwent Ee swimming once daily and rats in control group remain sedentary. After 14 days, echocardiographic measurements were performed and left ventricular ejection fraction (LVEF) and fractional shortening (LVFS), left ventricular diastolic diameter (LVIDd) and left ventricular systolic diameter (LVIDs) were obtained. The morphological structure of heart was detected by HE and Masson staining. Serum superoxide dismutase (SOD) and malondialdehyde (MDA) were measured by enzyme-linked immunosorbent assay. Cardiomyocytes apoptosis was detected by TUNEL method. The protein expression of myocardial hypertrophy marker protein B-type natriuretic peptide (BNP) and apoptotic marker protein (Bcl-2, Bax) in rat myocardial tissue was detected by Western blot.@*Results@#(1) Both LVFS and LVEF were significantly lower, and LVIDs and LVIDd were significantly larger in Ee group than those in control group (all P<0.01). The LVFS and LVEF in medium dose of Ber and high-dose Ber groups were significantly higher, and the LVIDs and LVIDd were significantly smaller than those in Ee group (all P<0.01). (2) The results of HE staining showed that the myocardial cells in control group were closely arranged, regular, normal in morphology, clear in structure, and uniform in staining. The myocardial cells of rats in Ee group were disarranged, cell staining was uneven, and vacuoles appeared in the cytoplasm. The disorder of myocardial cell arrangement and unequal staining in the medium dose of Ber were attenuated than in Ee group. The Masson staining results showed that the myocardial cells in control group were closely arranged, regular, normal in shape, clear in structure, and rarely blue-stained (fibrosis). Myocardial cells in rats in Ee group showed obvious fibrosis. The myocardial cell fibrosis in rats with medium dose of Ber was significantly reduced than exercise group. (3) MDA content in myocardial tissue of rats in Ee group was significantly higher than that of control group, and MDA content in myocardial tissue of rats in medium dose of Ber group was significantly lower than in Ee group (P<0.01). The SOD activity of myocardial tissue in rats was significantly lower than that of control group, while that of rats with medium dose of Ber was significantly higher than that of rats in Ee group (P<0.01). (4) TUNEL staining results showed that only a small amount of apoptosis myocardial cells were seen in control group, and a large number of apoptosis myocardial cells were seen in rats in Ee group. However, the number of apoptotic cardiomyocytes in medium dose of Ber was significantly lower than that in Ee group. The AI of rat cardiomyocytes was significantly higher than that of control group (P<0.01), and the AI of rat cardiomyocytes in median dose of Ber group was significantly lower than in Ee group (P<0.01). (5) BNP and Bax protein expression in the myocardial tissues of rats in Ee group were significantly higher than in control group (P<0.01). BNP and Bax protein expression in the myocardial tissues in median dose of Ber group were significantly lower than that of Ee group (P<0.01). The myocardial protein expression level of Bax was significantly higher, and the myocardial protein level of Bcl-2 was significantly lower in Ee group than in control group (both P<0.01), treatment with median dose of Ber could partly reverse above changes (both P<0.01).@*Conclusion@#Ber can attenuate exhaustion exercise induced myocardial injury and remodeling in rats, and the beneficial effects of Ber might possibly be mediated by reducing free radical release and cardiomyocytes apoptosis.

Research of the heart protective effect of exercise precondition mediated by calcitonin gene related peptide on acute exhaustion rats / 中华危重病急救医学

Objective To observe the heart protective effect of exercise preconditioning (EP) in the acute exhaustion exercise (EE) rats, and explore its action mechanism further. Methods Eighty healthy male Sprague-Dawley (SD) rats were divided into control group (C group), EP group, EE group, and EP+EE group randomly, with 20 rats in each group. The rats in EP and EP+EE groups were trained for 3 weeks according to the daily swimming for 60 minutes (swimming 15 minutes, resting 5 minutes, repeating 3 times) with 6 days each week. The rats in EE and EP+EE groups on the last 1 day after 3 weeks, 3% weight heavy weight was carried once for swimming EE. Two hours after the last EE, abdominal aortic blood and heart was harvested, the levels of serum MB isoenzyme of creatine kinase (CK-MB) and calcitonin gene related peptide (CGRP) were determined by enzyme linked immunosorbent assay (ELISA); the ultrastructure of myocardium was observed by optical microscopy; the levels of myocardial malondialdehyde (MDA) and superoxide dismutase (SOD) were determined by ELISA, the mRNA expression of myocardial CGRP was assayed by reverse transcription-polymerase chain reaction (RT-PCR), and the protein expression of myocardial CGRP was assayed by Western Blot. Results Compared with C group, the levels of serum CK-MB and myocardial MDA were significantly increased, serum CGRP content, myocardial SOD activity, and mRNA and protein expressions of myocardial CGRP were significantly decreased in EE group and EP+EE group. Compared with EE group, the levels of serum CK-MB and myocardial MDA in EP+EE group were decreased [CK-MB (U/L): 13.11±0.77 vs. 15.55±0.90, MDA (μmol/L): 389.57±49.60 vs. 709.08±160.49], the level of serum CGRP, and mRNA and protein expressions of myocardium CGRP were increased [serum CGRP (ng/L): 120.41±9.07 vs. 97.97±9.05, CGRP mRNA (2 -ΔΔCT): 0.45±0.09 vs. 0.14±0.02, CGRP protein (gray value): 0.78±0.08 vs. 0.41±0.04, all P < 0.05], the degree of myocardial injury was obviously alleviated. There was no significant difference in the indexes between the EP group and C group. Conclusion EP has the heart protective effect for the acute EE rats, and the mechanism is closely related to the endogenous protective substance CGRP.

Protective effect of trimetazidine for the rat myocardial tissue after exhaustion exercise / 解放军医学杂志

Objective To explore the protective effect of trimetazidine on the myocardial tissue of rats by observing the oxidative stress, apoptosis and energy metabolism in myocardial tissue of rats after exhausted exercise. Methods Thirty healthy adult male Wistar rats were randomly assigned to three groups (10 each): quiet control group (C), exhausted exercise group (E) and exhausted exercise plus trimetazidine group (TE). Exhausted exercise model was established by forcing the rats swim ceaselessly, rats in group TE received hydrochloric acid trimetazidine (10mg/kg) for intervention. The myocardial tissue of rats was collected after the last exhausted exercise. The myocardial tissue of rats was evaluated by HE staining. The concentrations of superoxide dismutase (SOD), glutathione peroxidase 1 (GSH-Px) and malondialdehyde (MDA) in rats' myocardial cell mitochondria were detected by spectrophotometry. RT-PCR and immunohistochemistry were performed to quantify the mRNA and protein levels of Bax, Bcl-2 and uncoupling protein 2 (UCP2) in myocardial tissue of rats. Terminal-deoxynucleoitidyl Transferase Mediated Nick End Labeling (TUNEL) assay was employed to detect the apoptotic rate of myocardial tissue. Results Compared with group C, the SOD and GSH-Px activities in groups E and TE were reduced (P<0.01), while the MDA activity was increased (P<0.01), and more obvious changes were in group E. The SOD and GSH-Px activities decreased, while the MDA activity increased in group E than in group TE (P<0.01). Compared with group C, the apoptotic rate of myocardial tissue increased in groups E and TE (P<0.01), and the highest apoptotic rate was in group E (P<0.01). Furthermore, the mRNA and protein levels of Bax were significantly elevated in groups E and TE (P<0.01), and the highest expression was in group E (P<0.01). The mRNA and protein levels of BCL-2 were significantly reduced in groups E and TE (P<0.01), and the lowest expression was in group E (P<0.01). Meanwhile, compared with group C, the mRNA and protein expression of UCP2 was significantly increased in groups E and TE (P<0.01). After treatment with hydrochloric acid trimetazidine, the UCP2 expression in group TE was relative decreased than in group E (P<0.01). Conclusion Trimetazidine can reduce the oxidative stress and apoptotic rate of myocardial tissue of rats after exhausted exercise, indicating it plays an important protective role for the myocardial tissue of rats.

Mechanism about exercise preconditioning protect myocardial by means of regulate NLRP3 inflammatory signal pathways on exhaustion exercise rats / 中华危重病急救医学

Objective To discuss the mechanism about exercise preconditioning (EP) protected myocardium by means of regulate NLRP3 inflammasome signal pathways on exhausted exercise rats. Methods The male Sprague-Dawley (SD) rats were randomly divided into four groups: normal control group (C group), no EP on exhausted exercise group (EE group), 3dEP + EE group, and 3wEP + EE group, with 12 rats in each group. In C group and EE group, the rats had not done exercise, while EE group took an exhausted swimming exercise with 3% heavy weight on tail at the end of 3 weeks; 3dEP + EE group and 3wEP + EE group exercised according to the standard of swimming for 60 minutes every day (swam 15 minutes, took a rest for 5 minutes, repeated 3 times), 6 days in a week, and were trained for 3 days and 3 weeks respectively, and took an exhausted swimming exercise on the last day. A light microscope and electron microscope were used to observe the myocardial histopathology and ultrastructure change, and enzyme linked immunosorbent assay (ELISA) was used to detect the levels of serum interleukin (IL-1β, IL-18, IL-6), hypersensitive C-reactive protein (hs-CRP), MB isoenzyme of creatine kinase (CK-MB), and brain natriuretic peptide (BNP). The protein expressions of NLRP3 and caspase-1 were detected by Western Blot. The correlations among all the parameters were analyzed by Pearson correlation analysis. Results Under the light microscope and electron microscope, the myocardial fiber morphological structure was normal, neatly, and no interstitial edema, muscle membrane damage or myocardial cell swellen was found in C group. In EE group, heart tissues were stained obviously uneven, a large number of myocardial fibers were fractured and messed, interstitial fibers were hyperplasiaed and edema moderately, much of myocardial cells were edema and necrosis, inflammatory cells were infiltrated, the number of average infiltration inflammatory cells was highest, mitochondria were edema seriously, part of the crest and a small number of membrane were blended together, fuzzy and crest were fractured, sarcomere were disordered; 3dEP + EE group and 3wEP + EE group heart tissues injuries were obviously alleviated, among the three groups, and the best results were in 3wEP + EE group. Compared with C group, the serum contents of IL-1β, IL-18, IL-6, hs-CRP, CK-MB, BNP and heart tissues protein expressions of NLRP3 and caspase-1 in EE group were significantly increased [IL-1β (μg/L): 18.77±1.28 vs. 12.00±1.55, IL-18 (μg/L): 236.79±15.73 vs. 150.74±7.09, IL-6 (μg/L): 59.31±9.17 vs. 34.65±2.89, hs-CRP (mg/L): 469.37±137.73 vs. 107.15±14.22, CK-MB (U/L): 15.57±0.91 vs. 7.40±0.40, BNP (ng/L): 532.08±63.44 vs. 386.96±34.77, NLRP3 protein (gray value): 0.66±0.07 vs. 0.16±0.06, caspase-1 protein (gray value): 0.96±0.08 vs. 0.48±0.06, all P 0.05]. A positive correlation was shown among IL-1β, IL-18, IL-6, hs-CRP, BNP, CK-MB, NLRP3, and caspase-1 (all P < 0.01). Conclusions EP can reduce inflammatory reaction by regulating the NLRP3 inflammatory signal pathways, and protect the myocardial injury. The protection of the heart by long-term EP is more obvious than that of short-term EP.

EFFECT OF OXYGEN ENRICHMENT OF ROOM AIR ON THE HEMORHEOLOGY OF SOLDIERS AFTER EXHAUSTION-EXERCISE AT 3700m ALTITUDE / 解放军医学杂志

To study the effect of oxygen enrichment of room air on the change of hemorheology of soldiers after high altitude hypoxia and exhaustion exercise at 3700 altitude, the oxygen concentration was increased to 24 0%～25 0% in the rooms at 3700m altitude, the change of hemorheology in 10 soldiers after they had 12h rest and sleep in the oxygen enrichment room was examined in no oxygen enrichment resting state and in oxygen enrichment state as well as after exhaustion exercise in no oxygen enrichment room and in oxygen enrichment room.Hematocrit (HCT), blood viscosity (?b), reduction viscosity (?r) and viscometric aggregation index (VAI) were higher after exhaustion exercise in no oxygen enrichment room as compared with those in no oxygen enrichment resting state, the difference was very significant or signifant ( P 0 05),?b, Plasma viscosity (?p), ?r were decreased after exhaustion exercise in no oxygen enrichment room ( P