Exercise combined with trimetazidine improves anti-fatal stress capacity through enhancing autophagy and heat shock protein 70 of myocardium in mice

METTL21C mediates autophagy and formation of slow-twitch muscle fibers in mice after exercise

Homeostasis is essential for muscle repair and regeneration after skeletal muscle exercise. This study investigated the role of methyltransferase-like 21C (METTL21C) in skeletal muscle of mice after exercise and the potential mechanism. First, muscle samples were collected at 2, 4 and 6 weeks after exercise, and liver glycogen, muscle glycogen, blood lactic acid and triglyceride were assessed. Moreover, the expression levels of autophagy markers and METTL21C in skeletal muscle were analyzed. The results showed that the expression levels of METTL21C and MYH7 in the gastrocnemius muscle of mice in the exercise group were significantly higher after exercise than those in the control group, which suggested that long-term exercise promoted the formation of slow-twitch muscle fibers in mouse skeletal muscle. Likewise, the autophagy capacity was enhanced with the prolongation of exercise in muscles. The findings were confirmed in mouse C2C12 cells. We discovered that knockdown of Mettl21c reduced the expression of MYH7 and the autophagy level in mouse myoblasts. These findings indicate that METTL21C promotes skeletal muscle homeostasis after exercise by enhancing autophagy, and also contributes to myogenic differentiation and the formation of slow muscle fibers.

Preoperative exercise training decreases complications of minimally invasive lung cancer surgery: A randomized controlled trial

OBJECTIVE

Limited evidence exists regarding the efficacy of preoperative exercise in reducing short-term complications after minimally invasive surgery in patients with non-small cell lung cancer. This study aims to investigate the impact of preoperative exercise on short-term complications after minimally invasive lung resection.

METHODS

In this prospective, open-label, randomized (1:1) controlled trial at Xiangya Hospital, China (September 2020 to February 2022), patients were randomly assigned to a preoperative exercise group with 16-day alternate supervised exercise or a control group. The primary outcome assessed was short-term postoperative complications, with a follow-up period of 30 days postsurgery.

RESULTS

A total of 124 patients were recruited (preoperative exercise group n = 62; control n = 62). Finally, 101 patients (preoperative exercise group; n = 51 and control; n = 50) with a median age of 56 years (interquartile range, 50-62 years) completed the study. Compared with the control group, the preoperative exercise group showed fewer postoperative complications (preoperative exercise 3/51 vs control 10/50; odds ratio, 0.17; 95% CI, 0.04-0.86; P = .03) and shorter hospital stays (mean difference, -2; 95% CI, -3 to -1; P = .01). Preoperative exercise significantly improved depression, stress, functional capacity, and quality of life (all P < .05) before surgery. Furthermore, preoperative exercise demonstrated a significantly lower minimum blood pressure during surgery and lower increases in body temperature on day 2 after surgery, neutrophil-to-lymphocyte ratio, and neutrophil count after surgery (all P < .05). Exploratory research on lung tissue RNA sequencing (5 in each group) showed downregulation of the tumor necrosis factor signaling pathway in the preoperative exercise group compared with the control group.

CONCLUSIONS

Preoperative exercise training decreased short-term postoperative complications in patients with non-small cell lung cancer.

Cardiorespiratory fitness and morbidity and mortality in patients with non-small cell lung cancer: a prospective study with propensity score weighting

INTRODUCTION

This study aimed to investigate the association between cardiorespiratory fitness (CRF) and perioperative morbidity and long-term mortality in operable patients with early-stage non-small cell lung cancer (NSCLC).

PATIENTS AND METHODS

This prospective study included consecutive patients with early-stage NSCLC who underwent presurgical cardiopulmonary exercise testing between November 2014 and December 2019 (registration number: ChiCTR2100048120). Logistic and Cox proportional hazards regression were applied to evaluate the correlation between CRF and perioperative complications and long-term mortality, respectively. Propensity score overlap weighting was used to adjust for the covariates. We performed sensitivity analyses to determine the stability of our results.

RESULTS

A total of 895 patients were followed for a median of 40 months [interquartile range 25]. The median age of the patients was 59 years [range 26-83], and 62.5% were male. During the study period, 156 perioperative complications and 146 deaths were observed. Low CRF was associated with a higher risk of death (62.9 versus 33.6 per 1000 person-years; weighted incidence rate difference, 29.34 [95% CI, 0.32 to 58.36] per 1000 person-years) and perioperative morbidity (241.6 versus 141.9 per 1000 surgeries; weighted incidence rate difference, 99.72 [95% CI, 34.75 to 164.70] per 1000 surgeries). A CRF of ≤ 20 ml/kg/min was significantly associated with a high risk of long-term mortality (weighted hazard ratio, 1.98 [95% CI, 1.31 to 2.98], p < 0.001) and perioperative morbidity (weighted odds ratio, 1.93 [1.28 to 2.90], p = 0.002) compared to higher CRF.

CONCLUSION

The study found that low CRF is significantly associated with increased perioperative morbidity and long-term mortality in operable patients with early-stage NSCLC.

High-intensity interval training alleviates exhaustive exercise-induced HSP70-assisted selective autophagy in skeletal muscle

This study was designed to probe the effect of chaperone-assisted selective autophagy (CASA) on the maintenance of proteostasis during exhaustive exercise and uncover the alteration of CASA in muscle fibers with pre-high-intensity interval training (HIIT) intervention-induced muscle adaptation in response to exhaustive exercise. Rats were randomly divided into a control group; an exhaustive exercise group; and an HIIT + exhaustive exercise group. Results show myofibril damage and BiP levels were increased after exhaustive exercise, and the levels of the HSP70, BAG3, ubiquitin, autophagy-related proteins, and their interactions were increased. HIIT intervention before exhaustive exercise could decrease myofibril injury and BiP levels, accompanied by down-regulation of HSP70/BAG3 complex and selective autophagy. In conclusion, exhaustive exercise promotes CASA to clear protein aggregation for keeping proteostasis in muscle fibers; pre-HIIT intervention improves myofibril injury and unfold protein response caused by exhaustive exercise, which might contribute to inhibit the augmentation of CASA.

Neuroprotective potential of trimetazidine against tramadol-induced neurotoxicity: role of PI3K/Akt/mTOR signaling pathways

Tramadol (TRA) causes neurotoxicity whereas trimetazidine (TMZ) is neuroprotective. The potential involvement of the PI3K/Akt/mTOR signaling pathway in the neuroprotection of TMZ against TRA-induced neurotoxicity was evaluated. Seventy male Wistar rats were divided into groups. Groups 1 and 2 received saline or TRA (50 mg/kg). Groups 3, 4, and 5 received TRA (50 mg/kg) and TMZ (40, 80, or 160 mg/kg) for 14 days. Group 6 received TMZ (160 mg/kg). Hippocampal neurodegenerative, mitochondrial quadruple complex enzymes, phosphatidylinositol-3-kinases (PI3Ks)/protein kinase B levels, oxidative stress, inflammatory, apoptosis, autophagy, and histopathology were evaluated. TMZ decreased anxiety and depressive-like behavior induced by TRA. TMZ in tramadol-treated animals inhibited lipid peroxidation, GSSG, TNF-α, and IL-1β while increasing GSH, SOD, GPx, GR, and mitochondrial quadruple complex enzymes in the hippocampus. TRA inhibited Glial fibrillary acidic protein expression and increased pyruvate dehydrogenase levels. TMZ reduced these changes. TRA decreased the level of JNK and increased Beclin-1 and Bax. TMZ decreased phosphorylated Bcl-2 while increasing the unphosphorylated form in tramadol-treated rats. TMZ activated phosphorylated PI3Ks, Akt, and mTOR proteins. TMZ inhibited tramadol-induced neurotoxicity by modulating the PI3K/Akt/mTOR signaling pathways and its downstream inflammatory, apoptosis, and autophagy-related cascades.

Exercise prevents fatal stress-induced myocardial injury in obese mice

Introduction

This study aimed to explore whether aerobic exercise (AE) can prevent fatal stress-induced myocardial injury.

Methods

Thirty C57BL/6J mice were divided into either a normal diet, high-fat diet, or high-fat diet plus AE (n=10 per group). The AE protocol consisted of eight weeks of swimming. At the end of the diet and AE interventions, the mice were stimulated with fatal stress caused by exhaustive exercise (forced weight-loaded swimming until exhaustion), after which cardiac function was evaluated using echocardiography, myocardial ultrastructure was examined using transmission electron microscopy, and myocardial apoptosis was assessed using western blotting and TUNEL. Mitophagy, mitochondrial biogenesis and dynamics, and activation of the macrophage migration inhibitor factor (MIF)/AMP-activated protein kinase (AMPK) pathway were evaluated using quantitative PCR and western blotting. Obesity phenotypes were assessed once per week.

Results

AE reversed high-fat diet-induced obesity as evidenced by reductions in body weight and visceral fat compared to obese mice without AE. Obesity exacerbated fatal stress-induced myocardial damage, as demonstrated by impaired left ventricular ejection fraction and myocardial structure. The apoptotic rate was also elevated upon fatal stress, and AE ameliorated this damage. Obesity suppressed mitophagy, mitochondrial fission and fusion, and mitochondrial biogenesis, and these effects were accompanied by suppression of the MIF/AMPK pathway in the myocardium of mice subjected to fatal stress. AE alleviated or reversed these effects.

Conclusion

This study provides evidence that AE ameliorated fatal stress-induced myocardial injury in obese mice. The cardioprotective effect of AE in obese mice might be attributed to improved mitochondrial quality.

Rhodiola pre-conditioning reduces exhaustive exercise-induced myocardial injury of insulin resistant mice

Myocardial injury reduction and recovery under acute cardiac stress are adversely impacted by insulin resistance (IR). We previously demonstrated that Rhodiola improved cardiac anti-stress capacity in mice. Thus, this study focuses on the preventive efficacy of Rhodiola on exhaustive exercise (EE)-induced myocardial injury of IR mice. An 8-week high-fat diet (HFD) model of IR mice was established. Rhodiola was administrated by garaging. After the 8-week intervention, half of the mice performed EE to simulate acute cardiac stress, and determine myocardial injury; The remaining mice were sacrificed following fasting to assess metabolic disorder. We found myocardial injury induced by EE in IR mice was worse and was alleviated by Rhodiola pre-conditioning. Further, the nuclear factor erythroid 2-related factor 2 (Nrf2)-related antioxidant system was impaired by HFD, while mitochondrial dynamic fusion and fission were activated by HFD as a physiological protective compensation. The Rhodiola administration rescued Nrf2 impairment and further facilitated mitochondrial fusion and fission. All these results indicate that Rhodiola is a potential treatment for the prevention of cardiac events in type 2 diabetes mellitus and metabolic syndrome patients, and the Nrf2-related antioxidant activity and mitochondrial dynamics are the proposed mechanisms.

Trimetazidine and exercise offer analogous improvements to the skeletal muscle insulin resistance of mice through Nrf2 signaling

INTRODUCTION

Insulin resistance (IR) plays a key role in the pathogenesis and clinical course of patients with multiple metabolic diseases and diabetes. This study aimed to explore the effect of trimetazidine (TMZ) on skeletal muscle IR in mice fed a high-fat diet (HFD) and explore the possible underlying mechanism.

RESEARCH DESIGN AND METHODS

In vivo, a HFD mouse IR model was adopted and TMZ and exercise were used to intervene. Postintervention the following were determined: blood levels of glucose and insulin, homeostasis model assessment of IR index, expression of skeletal muscle insulin signaling-related proteins phosphorylated insulin receptor substrate 1 (p-IRS1/IRS1) and phosphorylated protein kinase B (p-AKT/AKT), nuclear factor erythroid 2 related factor 2 (Nrf2) signaling pathway, and oxidative stress. In vitro, a palmitate-treated C2C12 myotube IR model was constructed. Cellular glucose uptake, p-IRS1/IRS1, and p-AKT/AKT were determined, and reactive oxygen species (ROS) production was analyzed based on treatments with specific small interfering RNA of Nrf2 with or without TMZ. Western blot was used to obtain the protein expression level and ROS production by functional analysis kits.

RESULTS

In vivo, TMZ and exercise decreased the blood glucose and insulin levels and homeostasis model assessment of IR index, increased skeletal muscle insulin signaling-related protein ratios of p-IRS1/IRS1 and p-AKT/AKT, and both interventions activated Nrf2 signaling and reduced oxidative stress production in HFD mice. In vitro, TMZ reduced the oxidative stress reaction, increased the ratios of p-AKT/AKT and p-IRS1/IRS1, and attenuated the insulin stimulation of PA-induced glucose uptake. However, in the absence of Nrf2, TMZ failed to resist the effects of IR.

CONCLUSIONS

This study showed that TMZ, like exercise, brought about marked improvements to HFD-induced skeletal muscle IR through TMZ, a common pathway with exercise in the form of Nrf2, regulating oxidative stress. We provide new evidence to support the use of TMZ for diabetes treatment.

Trimetazidine and exercise provide comparable improvements to high fat diet-induced muscle dysfunction through enhancement of mitochondrial quality control

Obesity induces skeletal muscle dysfunction. The pathogenesis of which appears to substantially involve mitochondrial dysfunction, arising from impaired quality control. Exercise is a major therapeutic strategy against muscle dysfunction. Trimetazidine, a partial inhibitor of lipid oxidation, has been proposed as a metabolic modulator for several cardiovascular pathologies. However, the effects of Trimetazidine on regulating skeletal muscle function are largely unknown. Our present study used cell culture and obese mice models to test a novel hypothesis that Trimetazidine could improve muscle atrophy with similar results to exercise. In C2C12 cells, high palmitic acid-induced atrophy and mitochondrial dysfunction, which could be reversed by the treatment of Trimetazidine. In our animal models, with high-fat diet-induced obesity associated with skeletal muscle atrophy, Trimetazidine prevented muscle dysfunction, corrected metabolic abnormalities, and improved mitochondrial quality control and mitochondrial functions similarly to exercise. Thus, our study suggests that Trimetazidine successfully mimics exercise to enhance mitochondrial quality control leading to improved high-fat diet-induced muscle dysfunction.

The Treatment of Rhodiola Mimics Exercise to Resist High-Fat Diet-Induced Muscle Dysfunction via Sirtuin1-Dependent Mechanisms

Muscle dysfunction is a complication of high-fat diet (HFD)-induced obesity that could be prevented by exercise, but patients did not get enough therapeutic efficacy from exercise due to multiple reasons. To explore alternative or supplementary approaches to prevent or treat muscle dysfunction in individuals with obesity, we investigated the effects of Rhodiola on muscle dysfunction as exercise pills. SIRT1 might suppress atrogenes expression and improve mitochondrial quality control, which could be a therapeutic target stimulated by exercise and Rhodiola, but further mechanisms remain unclear. We verified the lipid metabolism disorders and skeletal muscle dysfunction in HFD feeding mice. Moreover, exercise and Rhodiola were used to intervene mice with a HFD. Our results showed that exercise and Rhodiola prevented muscle atrophy and dysfunction in obese mice and activating the SIRT1 pathway, while atrogenes were suppressed and mitochondrial quality control was improved. EX-527, SIRT1 inhibitor, was used to validate the essential role of SIRT1 in salidroside benefit. Results of cell culture experiment showed that salidroside alleviated high palmitate-induced atrophy and mitochondrial quality control impairments, but these improvements of salidroside were inhibited by EX-527 in C2C12 myotubes. Overall, Rhodiola mimics exercise that activates SIRT1 signaling leading to improvement of HFD-induced muscle dysfunction.