Enzymatic and microstructural changes in the liver of experimental rats fed with fatty diet and fresh or heated soy oil concurrently

Aims. Consumption of heated edible oils may be harmful. The present study aimed to observe the histological changes due to concurrent consumption of soy oil (either fresh or heated) and fatty diet and the changes in the level of alanine transaminase (ALT) and alkaline phosphatase (ALP). Materials and Methods. Forty female Spraque-Dawley rats were equally divided into four groups (I to IV). All the rats in groups II, III and IV were ovariectomised. Rats in group I (control) were fed with 2% cholesterol diet, whereas the rats in groups II, III and IV were fed with 2% cholesterol diet fortified with 15% weight/weight (w/w) fresh soy oil (FSO), once heated soy oil (1HSO) and five times heated soy oil (5HSO) respectively, for 16 weeks. Blood was taken for liver enzymes and analysed before and after 16 weeks of study. At the end of the study the animals were sacrificed, and the liver was examined histologically. The specimens were weighed, formalin fixed and the sections were stained with hematoxylin and eosin. Results. Fresh, 1HSO and 5HSO soy oil caused significant increase in serum ALT and ALP compared to their base line values. Fresh, 1HSO and 5HSO soy oil caused microsteatosis, inflammation and necrosis of the liver tissues. However, there was no significant difference in the ALT and ALP enzyme levels amongst the oil fed groups. Conclusion. It is concluded that the effect of both fresh and heated soy oil on these parameters was not affected by repeated heating except for the inflammation.