Histological, Biochemical and Genetic Investigation of Liver Aging in Rats

BACKGROUND/AIMS: Aging is a chronic, complex and irreversible process that leads to functional deterioration in cells.Structural and functional changes occur in the liver during aging.This study aimed to determine age-related changes in rat liver tissue using histological, biochemical, and gene-expression analyses. MATERIALS AND METHODS:Wistar albino male rats were used in the study; two groups were formed: a young group (10 weeks) and an aged group (18 months).Blood and tissue samples were collected from the subjects while they were under general anesthesia.Liver enzymes were measured in blood samples.Gene expression levels of interleukin-6 (IL-6), nuclear factor kappa B (NF-kB), mammalian target of rapamycin (mTOR) protein complex, and caspase-3 (Cas-3) in liver tissues were evaluated by real-time polymerase chain reaction following total ribonucleic acid isolation and complementary DNA synthesis.Histological scoring was performed on tissues from the groups.Tissues were evaluated with hematoxylin-eosin, Masson's trichrome, periodic acid-Schiff, and Ki-67 proliferation index stains.RESULTS: Biochemically, significant increases in cholesterol, triglycerides, alanine transaminase, and alkaline phosphatase were observed in the aged group.Light microscopic examination revealed an increased number of Ki-67-positive and binucleated hepatocytes, vacuolization, sinusoidal congestion, bile-duct proliferation, and increased collagen in the aged group.While Cas-3 and mTOR gene expression increased significantly in the aged group, no differences were observed in IL-6 and NF-kB levels.CONCLUSION: Histological, apoptotic, and autophagic changes have been observed during physiological aging, and they are known to influence liver function.