Microcystin-LR regulates circadian clock and antioxidant gene expression in cultured rat cardiomyocytes

Abstract

BackgroundMicrocystins are waterborne environmental toxins that induce oxidative stress and cause injuries in the heart. On the other hand, many physiological processes, including antioxidant defense, are under precise control by the mammalian circadian clock.ResultsIn the present study, we evaluated the effect of microcystin-LR (MC-LR) on the rhythmic expression patterns of circadian and antioxidant genes in rat cardiomyocytes using the serum shock technique. We found that a non-toxic dose (10 μm) of MC-LR decreased the amplitudes of rhythmic patterns of clock genes, while it increased the expression levels of antioxidant genes.ConclusionsOur results indicate an influence of MC-LR on the circadian clock system and clock-controlled antioxidant genes, which will shed some light on the explanation of heart toxicity induced by MC-LR from the viewpoint of chronobiology.

A Review of Cardiovascular Toxicity of Microcystins

“…To date, a large number of studies have shown that MCs can induce cardiovascular toxicity in vivo and vitro directly [36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53]. Table 1 and Table 2 represent summaries of cardiovascular toxicity in in vivo and vitro studies, respectively.…”

“…In addition, MC-LR has recently been confirmed to inhibit the heart rate of Japanese Medaka (Oryzias Latipes) [44]. Currently, Xu et al [49] provided an explanation of the possible role of antioxidant enzymes in the toxicological mechanisms of MCs at the transcription level by treating H 9 C 2 (a kind of rat cardiomyocyte) cell lines with 10 μM MC-LR. The expression levels of cardiac rhythm and antioxidant genes were detected and the results suggested that the expression levels of rhythmic genes ( baml1, cry1, cry2, per1, per2 ) were inhibited, while the antioxidant genes ( catalase, ho-1, sod1, sod2 ) were upregulated.…”