Physiological damage in Algerian mouse Mus spretus (Rodentia, Muridae) exposed to crude oil

Small mammals have been used to predict ecotoxicological damage caused by metals in field studies and laboratory exposure. In natural ecosystems, rodents play an important role either as seed dispersers or food providers for various predators since they represent intermediate links in the food chain. Several studies have already focused on the effects of metals on wild rodents, but data provided on the effects of organic contaminants, such as crude oil, are scarce. Among the possible biological indicators, physiological parameters are useful because they reflect, accurately, the organism-environment interaction. The current study aimed: I) to evaluate the effects of the exposure to soil contaminated by crude oil in the Mus spretus mice and II) to select sensitive markers to crude oil pollution. Mice collected in free-contaminated areas were exposed to artificial soil contaminated by crude oil, and compared with animals housed in artificial non-contaminated soil (control soil). External signs such as lethargy and alopecia were observed in the first days of exposure. However, no changes in animals' body weight were recorded although changes in relative weight of some organs (liver, spleen and lungs) were observed. Furthermore, results also revealed increase in basal metabolic rate and decrease in exploratory and locomotor activity. Exposure to soil contaminated also caused dysfunction of the adrenal glands measured through fecal corticosterone levels. Data obtained highlight the relevance of using ex situ models, such as wild mice, and suggest a set of biological markers to predict and monitor environmental damage caused by crude oil exposure.