Diethylnitrosamine (DEN) is known as a potential hepatic carcinogen by single administration. This study was designed to measure the effects of DEN-induced cell damage on the triglyceride and cholesterol concentration in the liver, excluding dietary effects. Fertilized chicken eggs, 10 days before hatching, were randomly divided into three groups (n=20) and each egg was injected 10 ul of corn oil (vehicle control), 5 ug of DEN/10 ul and 10 ug of DEN/10 ul into yolk via air sac. After 48 hr and 96 hr incubation, the damage of the chick-embryo liver cell was investigated by electron microscopy and by measuring the concentration of lipid components (total cholesterol, free cholesterol, phospholipid and triglyceride). For eggs administered 10 ug of DEN and incuvated 96 hr, in hepatocyte, the nucleus membrane was roughed, the size of nucleolus was apparently increased and euchromatin was accumulated. Mitochondria were condensed and cristae, located mitochondrial inner membrane, were obscured. Additionally, the levels of triglyceride and cholesterol classes were significantly increased depend on the amount of DEN and incubation time. Especially, triglycerides were notably increased in the group treated with 10 ug DEN at 96 hr, but phospholipids, component of cell membrane, were decreased with significance. As a conclusion, carcinogen induced hepatic lesion was correlated with the changes in lipid component of liver.

Telomeres are the end of chromosomes and consist of a tandem repeat sequence of (TTAGGG)n and associated proteins. Telomerase is a ribonucleoprotein which act as a template for the synthesis of telomeric DNA. Telomeres are essential for chromosome stability and are related with cell senescence, apoptosis and cancer. Even though telomeres and telomerase have been studied extensively, very little is known about telomere dynamics in embryonic cells. This study was carried out to analyze the telomeres distribution and telomerase activity of chicken cells during embryonic and developmental stages. The target cells for analysing were sperms, ovulated ova, early embryonic cells and the cells from brain, heart, liver, kidney and germinal tissue in fetus. Telomeres distribution on target cells was analyzed by Q-FISH (Quantitation-Fluorescence in situ Hybridization) techniques using a chicken telomere repeat probe. Telomerase activity was performed by TRAP assay (Telomeric repeat Amplification Protocol) with target DNA. In results, the telomeres of chicken were found at the ends of all chromosomes. In addition, chicken had interstitial telomeres on chromosomes 1, 2 and 3. Telomerase activity was highly detectable in early embryonic cells, germinal tissues and kidney cells. Whereas telomerase activity was gradually down-regulated when the organs, including brain, heart, and liver, were developed from embryos. In the distribution of telomeric DNA on the embryonic and developmental stages, most of the cells was gradually decreased in telomere quantity during ontogenesis.