Metallothionein-I/II null cardiomyocytes are sensitive to Fusarium mycotoxin butenolide-induced cytotoxicity and oxidative DNA damage.

Previous studies revealed butenolide (BUT), a Fusarium mycotoxin distributes extensively, induced myocardial oxidative damage, which could be abated by antioxidants such as glutathione. Metallothionein (MT) has proved to attenuate several oxidative cardiomyopathies via its potent antioxidant property. The present study is therefore undertaken to investigate the protective potential of the endogenous expression of MT against BUT-induced myocardial toxicity. Primary cultures of neonatal cardiomyocytes from MT-I/II null mice along with the corresponding wild-type mice will be utilized to determine the possible mechanistic properties of MT. BUT treatment to the cardiomyocytes evoked significant cytotoxicity as evidenced by morphological changes and concentration- and time-dependent reductions in cell viability. Additionally, BUT treatment remarkably increased reactive oxygen species (ROS) production in the cardiomyocytes of both MT-I/II null and wild-type mice. As a result, noticeable DNA damage in both cardiomyocytes was detected by alkaline comet assay. Furthermore, the comparison between the MT-I/II null and wild-type cardiomyocytes indicated that ROS production in the cardiomyocytes from the MT-I/II null mice was higher than from wild-type mice. DNA damage as evaluated by percentage of comet tail DNA, tail length and tail moment was more severe in the MT-l/II null cardiomyocytes than in wild-type myocytes. And in agreement with those results mentioned above, the MT-l/II null cardiomyocytes were more sensitive to BUT-induced cytotoxicity than wild-type cardiomyocytes. Taken together, these findings clearly show that basal MT can efficiently attenuate BUT-induced cytotoxic injuries in cardiomyocytes via the inhibition of intracellular ROS production, and associated DNA damage.