Localization and expression of heat shock protein 70 with rat myocardial cell damage induced by heat stress in vitro and in vivo

Abstract

The aim of the present study was to investigate the association between heat shock protein (Hsp) 70 expression kinetics and heat stress‑induced damage to rat myocardial cells in vitro and in vivo. The results showed that the activity of heart injury‑associated enzymes, including aspartate aminotransferase and creatine kinase, significantly increased and myocardial cells developed acute histopathological lesions; this therefore suggested that heat stress altered the integrity of myocardial cells in vitro and in vivo. Levels of Hsp70 in vitro decreased following the initiation of heat stress and then steadily increased until heat stress ceased at 100 min; however, in vivo studies demonstrated a gradual increase in Hsp70 levels in the heart cells of rats from the initiation of heat stress, followed by a sharp decline at 100 min. These results indicated that the cells sustained different degrees of injury in vivo compared with those sustained in vitro, this may be due to different regulatory mechanisms in the two environments. Intracytoplasmic Hsp70 signaling was significantly reduced at 60 min in vitro, compared with that of the in vivo study, indicating that Hsp70 consumption may have exceeded its production prior to 60 min of heat stress, and following 60 min the cells produced sufficient Hsp70 protein for their protection against heat stress. Hsp70‑positive signals in the cytoplasm of heart cells in vivo were more prominent in the intact areas compared with those of the degenerated areas and the density of Hsp70‑positive signals was significantly reduced following 60 min of heat stress. In conclusion, comprehensive comparisons of enzymes, cell morphology and Hsp70 levels indicated that decreased levels of Hsp70 were associated with the reduced protective effect on myocardial cells in vitro and in vivo.

In vitro evaluation of aspirin-induced HspB1 against heat stress damage in chicken myocardial cells

“…These enzymes are generally designated as cardiomyocyte damage-related enzymes and further regarded as important indicators for judging acute myocardial injury (Amani et al 2013;Chen et al 2013;Chon et al 2013;Wu et al 2013), especially CK-MB (Zeren et al 2013). In addition to these enzymes, cytopathological changes like swollen in size, uneven staining in the cytoplasm and vacuolar degeneration were clearly identified in a lot of researches (Chen et al 2015;Tang et al 2013). According to these myocardial cell damage markers, it is clearly to find that overexpressed HspB1 by ASA was accompanied with relatively slight heat stress injury in myocardial cells, while severe cell damage appeared when ASA was not involved and the HspB1 level In the ASA-HS group and the ASA group, HspB1 concentration almost kept two orders of magnitude higher than the HS group in which the only HspB1 inducer was high temperature…”

Multistage Targeting Strategy Using Magnetic Composite Nanoparticles for Synergism of Photothermal Therapy and Chemotherapy

“…Next, we investigated the mechanism of the synergism of PTT and chemotherapy‐targeting mitochondria at the protein level by western blot (Figure B). The heat shock protein 70 (Hsp70) is typically synthesized in response to heat stress to protect the cell from thermal damage . Thus, Hsp70 expression was monitored to evaluate the heat stress of the cells.…”

A Photo‐Stable Indocyanine Green and Rapamycin Co‐Delivery System Based on Poly(Glutamic Acid)‐Modified Manganese Phosphate for Synergetic Tumor Therapy

“…One possible reason is that LC3‐II itself may also be degraded by autophagy . Heat shock protein 70 (HSP70) is usually produced in response to thermal or oxidative stress . Therefore, HSP70 expression was also detected by Western blot.…”