Effect of tinuvin 770 [a light stabilizer] on ventricular cardiomyocytes of albino rats and possible protective role of lycopene. toxicological and histological study

ABSTRACT

Tinuvin 770 is a substance used as an ultraviolet light and radiation stabilizer employed universally in the manufacture of plastic materials. It has recently been suggested to possibly cause cardiovascular manifestations. Lycopene is a potent antioxidant carotenoid without provitamin A activity. It is present in many fruits and vegetables; however, tomatoes and processed tomato products constitute its major sources. Lycopene has recently gained great attention for its protective effect against several pathological disorders, particularly coronary heart diseases [CHDs]. This work aimed at evaluating the potential toxic effects of tinuvin 770 on rat myocardium, as well as the possible cardioprotective role of pre-and concomitant lycopene administration, both histologically and biochemically. 50 adult male rats were divided among 5 equal groups. Group I served as a control group. Group II received lycopene orally [4.6 mg/ kg b.w/ day] for 9 weeks. Group III received tinuvin 770 [lmg/ kg b.w] intraperitoneally 3 times a week for 5 weeks. Group IV received lycopene simultaneously with tinuvin for 5 weeks. Group V received lycopene 4 weeks prior to and concurrent with tinuvin 770 for another 5 weeks. The last urine samples and myocardial specimens were collected at the end of the experiment for estimation of norepinephrine levels and histological examination of the ventricular cardiomyocytes respectively. Tinuvin 770 evoked marked increase in norepinephrine urine levels and evident myocardial lesions in group III rats included waviness, myocytolysis and focal hypereosinophilia of the muscle fibers. Ultrastructurally, evident alterations of the myofibrils, mitochondria, sarcoplasmic reticulum and intercalated discs were revealed. On simultaneous lycopene and tinuvin administration [group IV], mild amelioration of the myocardial lesions was depicted, whereas prior treatment with lycopene [group V] resulted in considerable myocardial protection. Tinuvin 770 might be considered as a cardiotoxic agent, and lycopene is especially beneficial in ameliorating its effects