High throughput phenotyping of left and right ventricular cardiomyopathy in calcineurin transgene mice

Naoxintong capsule attenuates heart damage after ischemic stroke via Nuclear factor-κB / Pyrin domain-containing protein 3 / Caspase-1 signaling

ETHNOPHARMACOLOGICAL RELEVANCE

Ischemic stroke (IS) is a major cause of mortality. Inflammation exerts an essential part of brain-heart communication after IS. Naoxintong capsule (NXT), derived from the classical Traditional Chinese Medicine (TCM) formulation Bu-Yang-Huan-Wu-Tang, are extensively employed in China to manage IS, myocardial infarction (MI), and atherosclerosis. Previous clinical studies have demonstrated the protective effects of NXT in anti-atherosclerosis, cerebral infarction, angina, and acute coronary syndrome. However, the potential therapeutic mechanism of NXT for IS remains unknown.

AIM OF THE STUDY

This study aims to investigate a potential mechanism for enhancing brain-heart interaction following an ischemic stroke.

MATERIALS AND METHODS

C57BL/6J mice underwent permanent middle cerebral artery occlusion (MCAO) for durations of 6, 12, and 24 h. The effects of NXT on the brain were observed via TTC, Nissl and TUNEL staining, immunofluorescence staining, and Zea-Longa scores. Simultaneously, the effects of NXT on the heart were evaluated via H&E staining and echocardiography. Inflammatory factors in heart and serum were determined via ELISA or luminex liquid suspension chip detection. Network pharmacology predicted the targets and signaling pathways of NXT. The binding affinity between potential targets and active compounds of NXT was assessed through molecular docking. The expression levels of IκBα, IKKβ, NF-κB, NLRP3, and caspase-1 were evaluated via Western blotting.

RESULTS

The Zea-Longa scores, infarct rate, and the rate of apoptosis in the brain at 6, 12, and 24 h of MCAO mice were markedly decreased by NXT. Additionally, they clearly enhanced the NeuN positive rate and prevented microglia from activating at 24 h. NXT significantly reduced the level of myocardial injury biomarkers (Lactate dehydrogenase (LDH) and Creatine kinase isoenzyme MB (CK-MB) at 24 h, N-terminal pro-brain natriuretic peptide (NT-pro BNP) at 6, 12, and 24 h), improved ejection fraction, fractional shortening, stroke volume, and cardiac output at 24 h. The levels of MIP-1α in cardiac tissue and IL-1β in serum were both markedly lowered by NXT. Furthermore, the NF-κB/NLRP3/caspase-1 signaling pathways may be potential mechanisms of NXT. Molecular docking indicated that IKKβ, IκBα, NF-κB, NLRP3, and caspase-1 may serve as potential targets for the action of representative active ingredients in NXT. NXT could reduce the expression levels of IKKβ, NF-κB, NLRP3, and caspase-1 in brain and heart tissues while increasing the expression of IκBα.

CONCLUSIONS

Our study illustrates that NXT efficiently attenuated inflammation in the brain and heart by blocking the NF-κB/NLRP3/caspase-1 signaling pathway. These findings provide appealing insights into the multi-organ perspective on human health via identifying shared inflammatory impacts and heart-brain linkages.

Experimental ischaemic stroke induces transient cardiac atrophy and dysfunction

BACKGROUND

Stroke can lead to cardiac dysfunction in patients, but the mechanisms underlying the interaction between the injured brain and the heart are poorly understood. The objective of the study is to investigate the effects of experimental murine stroke on cardiac function and molecular signalling in the heart.

METHODS AND RESULTS

Mice were subjected to filament-induced left middle cerebral artery occlusion for 30 or 60 min or sham surgery and underwent repetitive micro-echocardiography. Left ventricular contractility was reduced early (24-72 h) but not late (2 months) after brain ischaemia. Cardiac dysfunction was accompanied by a release of high-sensitive cardiac troponin (hsTNT (ng/ml): d1: 7.0 ± 1.0 vs. 25.0 ± 3.2*; d3: 7.3 ± 1.1 vs. 52.2 ± 16.7*; d14: 5.7 ± 0.8 vs. 5.2 ± 0.3; sham vs. 60 min. MCAO; mean ± SEM; *p < 0.05); reduced heart weight (heart weight/tibia length ratio: d1: 6.9 ± 0.2 vs. 6.4 ± 0.1*; d3: 6.7 ± 0.2 vs. 5.8 ± 0.1*; d14: 6.7 ± 0.2 vs. 6.4 ± 03; sham vs. 60 min. MCAO; mean ± SEM; *p < 0.05); resulting from cardiomyocyte atrophy (cardiomyocyte size: d1: 12.8% ± 0.002**; d3: 13.5% ± 0.002**; 14d: 6.3% ± 0.003*; 60 min. MCAO vs. sham; mean ± SEM; **p < 0.01; *p < 0.05), accompanied by increased atrogin-1 and the E3 ubiquitin ligase murf-1. Net norepinephrine but not synthesis was increased, suggesting a reduced norepinephrine release or an increase of norepinephrine re-uptake, resulting in a functional denervation. Transcriptome analysis in cardiac tissue identified the transcription factor peroxisome proliferator-activated receptor gamma as a potential mediator of stroke-induced transcriptional dysregulation involved in cardiac atrophy.

CONCLUSIONS

Stroke induces a complex molecular response in the heart muscle with immediate but transient cardiac atrophy and dysfunction.

Guidelines for measuring cardiac physiology in mice

Cardiovascular disease is a leading cause of death, and translational research is needed to understand better mechanisms whereby the left ventricle responds to injury. Mouse models of heart disease have provided valuable insights into mechanisms that occur during cardiac aging and in response to a variety of pathologies. The assessment of cardiovascular physiological responses to injury or insult is an important and necessary component of this research. With increasing consideration for rigor and reproducibility, the goal of this guidelines review is to provide best-practice information regarding how to measure accurately cardiac physiology in animal models. In this article, we define guidelines for the measurement of cardiac physiology in mice, as the most commonly used animal model in cardiovascular research.

Listen to this article’s corresponding podcast at http://ajpheart.podbean.com/e/guidelines-for-measuring-cardiac-physiology-in-mice/.