Comparative evaluation of heat stress and fuel Vapour exposure on hepatic histology and liver function Biomakers in Adult Wistar Rats

Environmental stressors such as extreme heat and fuel vapour exposure have become significant public health concerns due to their adverse effects on various organs of the body, particularly the liver, which plays a central role in metabolism, detoxification, and maintaining physiological homeostasis. Prolonged exposure to these stressors may induce oxidative stress, inflammation, and structural damage to hepatic tissues, thereby impairing liver function.
This study was designed to comparatively evaluate the effects of evaluate the effects of heat stress and fuel vapour exposure on hepatic histology and liver function biomakers in Adult wistar .  A total of 12 healthy adult albino Wistar rats weighing between 150-200g were used for the study and randomly assigned into 3 groups, comprising a control group, an extreme heat exposure group, and an extreme fuel vapour exposure group. The experimental exposures were carried out for 2 weeks. At the end of the exposure period, blood samples were collected for biochemical analysis of liver enzymes, including alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP). Liver tissues were also harvested and processed for histological examination using Haematoxylin and Eosin staining techniques.
The results showed significant increases in liver enzyme activities in both the heat-exposed and fuel vapour-exposed groups compared with the control group (p < 0.05). The heat-exposed group recorded AST, ALT, and ALP values of 117.50 ± 1.44 IU/L, 126.50 ± 0.86 IU/L, and 182.24 ± 2.19 IU/L, respectively, compared with control values of 94.00 ± 2.31 IU/L, 92.00 ± 0.58 IU/L, and 121.31 ± 1.77 IU/L. The fuel vapour-exposed group demonstrated the highest enzyme levels, with AST, ALT, and ALP values of 187.50 ± 4.33 IU/L, 237.50 ± 1.44 IU/L, and 316.22 ± 3.51 IU/L, respectively, indicating significantly greater hepatotoxicity than heat exposure (p < 0.05).
Histological examination revealed normal hepatic architecture in the control group, characterized by preserved hepatic lobules, well-arranged hepatocyte cords, and normal central veins. The fuel vapour-exposed group exhibited mild diffuse inflammatory cell infiltration and mild disorganization of the central vein. The heat-exposed group also demonstrated diffuse inflammatory cell infiltration but showed moderate stromal degeneration, indicating structural alterations in hepatic tissue.
In conclusion, both extreme heat exposure and fuel vapour exposure adversely affected liver structure and function in adult Wistar rats. However, fuel vapour exposure produced more pronounced biochemical alterations and greater hepatotoxic effects than extreme heat exposure. These findings highlight the potential occupational and environmental health risks associated with prolonged exposure to these stressors and emphasize the need for preventive measures to minimize liver damage in exposed populations.