RESEARCH ARTICLE Liver disorders related to exposure to gasoline fumes in male rats and role of fenugreek seed supplementation Abeer E. Abdrabouh 1 Received: 13 May 2018 /Accepted: 22 January 2019 # Springer-Verlag GmbH Germany, part of Springer Nature 2019 Abstract Progressive effects of inhalation of gasoline fumes on the liver and the protective potential with fenugreek seed supplementation were evaluated in adult male rats. Twenty-four rats were divided into four groups, unexposed control and fenugreek groups, as well as exposed groups to gasoline fumes for 6 h/6 days/week for 10 weeks, with and without supplementation of fenugreek seed powder in food (5%w/w). Exposure to gasoline fumes resulted in a significant elevation in serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, gamma-glutamyl transferase, total bilirubin, total cholesterol, total triglycer- ides, and low-density lipoprotein, along with a significant decrease in high-density lipoprotein, total protein, and albumin contents compared to the control. Meanwhile, liver oxidative stress markers, malondialdehyde, hydrogen peroxide, and nitric oxide, were highly detected with decreased antioxidants, superoxide dismutase and catalase. Also, levels of inflammatory markers, interleukin(IL)-1β and IL-6, were significantly elevated with fibrotic markers, transforming growth factor (TGFβ1), fibroblast growth factor (FGF1), and collagen I. Histopathological studies illustrated that rats exposed to gasoline fumes have degenerated hepatocytes with cellular infiltration and necrotic areas, along with remarkable deposition of collagen fibers, suggesting an incidence of liver fibrosis. Administration of fenugreek seeds, rich with antioxidant and anti-inflammatory com- ponents, during gasoline exposure showed significant amelioration through suppressing oxidative stress and inflammation. Keywords Air pollution . Gasoline . Oxidative stress . Liver . Cytokines . Fibrosis . Histopathology Introduction Gasoline is a complex mixture of short-chain organic com- pounds, light-chain volatile compounds, and heavy-chain hy- drocarbons (Azari et al. 2012). The light-chain compounds (benzene, toluene, and xylene) known as BTX compounds are highly volatile that could be gradually released into the air (Abubakar et al. 2013). Millions of people are vulnerable to inhale these chemicals either at gasoline refueling stations, workshops of motor mechanics, or workers in petroleum com- panies during production and transportation processes (El- Ghazaly et al. 2016). Gasoline components have shown to modulate the normal physiological and immune response in humans (Abdrabouh et al. 2017) and animals (El-Wakf et al. 2018). Animal studies revealed that gasoline exposure is related to variant impacts including lung injury (Sourour et al. 2012), bone marrow in- jury and hematotoxicity (El-Wakf et al. 2018), genotoxicity (Moro et al. 2013), and hepatotoxicity (Uboh et al. 2012). The liver is an important organ that possesses metabolic, catabolic, anabolic, immune, and detoxifying functions (Itoh et al. 2016) and characterized by high regenerative capacity (Khan and Mudan 2007). Benzene and other related hydrocarbons of gasoline were reported to be metabolized in the liver through intermediate epoxides (superoxide anion, hydrogen peroxide, hydroxyl radicals) that are highly reactive to bind with hepatic microsomal proteins and nucleic acids, leading to cytotoxic effects (Gali et al. 2012). The expression of gasoline-induced liver injury is usually detected biochemically by estimation of some plasma enzymes and lipids. Elevation of liver enzymes and cholesterol are common in monitoring damage in liver cells (Uboh et al. 2012). However, injury is also related to the inflammatory process, where non-parenchymal cells, such Responsible editor: Philippe Garrigues * Abeer E. Abdrabouh abeer_ss2002@yahoo.com 1 Zoology Department, Faculty of Science, Mansoura University, Mansoura, Egypt Environmental Science and Pollution Research https://doi.org/10.1007/s11356-019-04307-x