All issues > Volume 44(11); 2001

Original Article

J Korean Pediatr Soc. 2001;44(11):1262-1268. Published online November 15, 2001.

The Effect of Tumor Necrosis Factor-α in Cultured Neonatal Rat Cardiomyocytes

Su Jin SJ Kim¹, Dong Seok DS Lee¹, Ok O Ko², Il Soo IS Mun², Bok Hyun BH Ko², Yong Wook YW Jung²

¹Department of Pediatrics, College of Medicine, Dongguk University, Kyungju, Korea
²Department of Anatomy, College of Medicine, Dongguk University, Kyungju, Korea

Correspondence Dong Seok DS Lee ,Email: lds117@dumc.or.kr

Abstract

Purpose
: Tumor necrosis factor-α(TNF-α) is a pro-inflammatory cytokine that has been implicated in the pathogenesis of cardiovascular disease. Serum levels of TNF-α are elevated in many human cardiac related pathogenic conditions, including heart failure. It is well known that TNF-α inhibits myocardial contractility and induces apoptosis of adult rat cardiomyocytes via stimulation of TNF receptor 1. But pathophysiologically relevant low levels of TNF-α can not induce apoptosis of neonatal cardiomyocytes. So, we evaluated the effects of different concentrations of TNF-α in cultured rat neonatal cardiomyocytes : apoptosis or necrosis.
Methods
: Neonatal ventricular myocytes were isolated from 3-day-old rats by stepwise collagenase dissociation, and the cells were cultured for 3 days. After that, cardiomyocytes were treated with low(25 ng/mL) and high(250 ng/mL) concentration of TNF-α for 48 hours. Apoptosis was determined by terminal deoxynucleotidyl transfer-mediated end labelling(TUNEL) staining, and cell viability was evaluated by lactate dehydrogenase(LDH) measurements using cell culture supernatants.
Results
: Low dose TNF-α did not induce apoptosis compared with controls(10.5±3.5% : 10.4±4.3%). And high dose TNF-α also did not induce significant apoptosis(10.2±3.6% : 10.4±4.3%). There was no detectable morphological changes of cardiomyocytes after low and high concentration of TNF-α treatment. LDH levels after TNF-α treatment was not significant compared with control(control : low : high, 3.2±0.1% : 3.1±0.2% : 3.3±0.3%).
Conclusion
: Our results suggest that high concentration of TNF-α alone can not induce apoptosis and significant cytotoxicity in neonatal rat cardiomyocytes.

Keywords :TNF-α, Neonatal rat, Cardiomyocyte, Apoptosis