A light stabilizer Tinuvin 770-induced toxic injury of adult rat cardiac myocytes.

Tinuvin 770/bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate is a worldwide used light stabilizer for plastic materials like polyolefins. Tinuvin 770 is a biologically active component of polypropylene tubes. Glossmann and his study group managed to extract this compound by aqueous or organic solvents from laboratory plastic tubes, and propose that Tinuvin 770 is a potent blocker of L-type Ca(2+)-channel through the phenylalkylamine and benzothiazepine-selective drug binding domains of the alpha(1) subunit of the receptor [Proc. Natl. Acad. Sci. U.S.A. 90 (1993) 9523]. We examined the direct morphological effect of Tinuvin 770 in give 25nmol, 0, 30, 60, 120 minute exposure time in isolated cardiomyocytes from adult rats. Incubation of myocytes with Tinuvin resulted in a progressive decline of rod-shaped and viable cells. It was accompanied by an increase in number of hypercontracted myocytes with microbleb formation compared to control and depletion of ATP level. In summary, our results demonstrate that plasma membrane damage and hypercontraction are manifestations of Tinuvin-induced injury of isolated cardiomyocytes.