Histological and Biochemical Effects of Cigarette Smoke on the Liver of Wistar Rats

Abstract

Aims: This work aims at determining the effect of cigarette smoke on the liver of albino Wistar rats, to evaluate the histological, as well as the biochemical changes in the adult albino rat’s liver and to elucidate the relationship between exposure period and effect. Study Design: An experimental study which lasted for 4 weeks was conducted at the Animal House of The College of Health Sciences, Nnamdi Azikiwe University, Nnewi campus. Methodology: Twenty four (24) adult albino Wistar rats were divided into four groups (A, B, C and D) each consisting of six rats. The average weight of each group was taken. Group A (normal control) had no exposure to cigarette smoke throughout the period of experiment. Groups B, C and D were exposed to cigarette smoke for two, three and four weeks respectively. The duration of exposure for each cigarette is 10±4 minutes and one hour interval was left between burning of each cigarette. After the experiment, blood samples were collected through direct cardiac punctures and delivered into plain test tubes for biochemical assay, and the animals painlessly sacrificed under chloroform anesthesia. The liver was excised, fixed in 10% formal saline for 48 hours and processed using paraffin wax processing techniques. Results: Rats in groups B, C and D showed varying degrees of loss of appetite, moderate irritability and breathing difficulties with significant decrease in body weights after second and third weeks (P=.001). Significant increase in aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities between the control and test groups was observed (P=0.000). Histologicaly, the liver of rats in group C shows marked necrosis and fatty deposition. Conclusion: The study reveals adverse effect of passive cigarette smoke on the liver morphology and biochemistry of the animal model. The need for similar study in humans is advocated.