Long-term exposure to crotonaldehyde causes heart and kidney dysfunction through induction of inflammatory and oxidative damage in male Wistar rats

Abstract

Crotonaldehyde is a ubiquitous hazardous pollutant, present in cigarette smoke and automobile exhaust and is endogenously generated by lipid peroxidation. Most of the current studies focus on its lung toxicity. However, there have been few investigations on the cardiac and renal toxicity caused by crotonaldehyde exposure. We hypothesized that oral intake of crotonaldehyde can cause inflammatory and oxidative/nitrosative damage to the heart and kidneys. Therefore, we treated male rats with crotonaldehyde by gavage at 0, 2.5, 4.5, and 8.5 mg/kg/day for 120 d and evaluated the alterations in histological and serological parameters, oxidative state, and inflammation responses to explore the roles of crotonaldehyde-induced oxidative/nitrosative stress and inflammation in the heart and kidney dysfunction and to explore the relationship between heart and kidney dysfunction. We found that body weight increment, as well as heart and kidney coefficients decreased with an increasing crotonaldehyde dosage. Histological examinations indicated that crotonaldehyde exposure led to focal myocardial necrosis, cardiac fibrosis, renal tubular epithelial cell edema, and renal lymphocyte infiltration. We also assessed the impact of crotonaldehyde treatment on oxidative/nitrosative stress markers, antioxidant enzymes, inflammatory biomarkers, heart/kidney functional markers, and angiotensin II-aldosterone-brain natriuretic peptide (AngII-ALD-BNP) levels. Overall, we found that proinflammatory cytokine and malondialdehyde levels increased in a dose-dependent manner. Furthermore, crotonaldehyde treatment (4.5 and 8.5 mg/kg) significantly prevented the upregulation of antioxidant enzyme activity, thereby increasing oxidative/nitrosative stress (p < 0.05). Moreover, we found that the levels of AngII and ALD increased, whereas the levels of BNP decreased, consistent with heart and kidney dysfunction. Collectively, these results suggest that long-term, low-dose crotonaldehyde exposure leads to an imbalance in AngII-ALD-BNP levels, which mediates cardiac hemodynamic changes causing internal oxidative/nitrosative stress and inflammatory reactions, leading to renal and cardiac dysfunction in male rats.

Keywords:

• Crotonaldehyde
• kidney
• heart
• histological alteration
• oxidative stress
• nitrosative stress
• inflammatory damage
• AngII-ALD-BNP

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was supported by the Natural Science Foundation of Shandong Province [grant number ZR2016YL016], Shandong, PR China.