Effects of Simulated Heat Waves on ApoE-/- Mice

Chunling Wang,Shuyu Zhang,Shuanghe Shen,Ying Tian,Baojian Wang

doi:10.3390/ijerph110201549

Abstract

The effects of simulated heat waves on body weight, body temperature, and biomarkers of cardiac function in ApoE-/- mice were investigated. Heat waves were simulated in a meteorological environment simulation chamber according to data from a heat wave that occurred in July 2001 in Nanjing, China. Eighteen ApoE-/- mice were divided into control group, heat wave group, and heat wave BH4 group. Mice in the heat wave and BH4 groups were exposed to simulated heat waves in the simulation chamber. Mice in BH4 group were treated with gastric lavage with BH4 2 h prior to heat wave exposure. Results showed that the heat waves did not significantly affect body weight or ET-1 levels. However, mice in the heat wave group had significantly higher rectal temperature and NO level and lower SOD activity compared with mice in the control group (p < 0.01), indicating that heat wave had negative effects on cardiac function in ApoE-/- mice. Gastric lavage with BH4 prior to heat wave exposure significantly reduced heat wave-induced increases in rectal temperature and decreases in SOD activity. Additionally, pretreatment with BH4 further increased NO level in plasma. Collectively, these beneficial effects demonstrate that BH4 may potentially mitigate the risk of coronary heart disease in mice under heat wave exposure. These results may be useful when studying the effects of heat waves on humans.

Highlights

IntroductionAs a type of extreme weather, have significant impacts on human health [1]
Heat waves, as a type of extreme weather, have significant impacts on human health [1]
Our results showed that ET-1 levels in the three groups of ApoE-/- mice showed no significant differences after heat wave exposure, the Nitric Oxide (NO) level in the heat wave group was 10.36 μmol/L higher than that in the control group, implying that heat wave exposure increased vasodilation and heat dissipation in ApoE-/- mice, as a defense mechanism against heat-induced increase in body temperature

Summary

Introduction

As a type of extreme weather, have significant impacts on human health [1]. Duration and frequent occurrence of high-temperature weather leads to increased hospitalization and mortality of patients with cardiovascular disease. The number of deaths from cardiac events caused by hot weather in China has increased and contributed to the increasing prevalence of coronary heart disease in China, which reached 6.49% in 2004 [2]. The average summer temperature in Nanjing has shown a significant upward trend, with more frequent occurrence of heat waves than the national average, likely attributable to global warming [3]. The rate of heart diseases such as coronary disease has significantly increased in Nanjing over the years [4,5]

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Conclusion