Abstract
► We examine the biomonitoring potential of the wild libyan jird,
Meriones libycus towards accidental heavy metal (Cd, Cu, Hg, Ni & Pb) exposure. ► We set up baseline and metal-induced profiles of the animal’s physiology and hematology versus other small mammalian species. ► The specific metal-related stress hemogram shows alterations in red blood cell indices and in the leukogram profile. ► Metal-induced adverse effects on the stress profile of serum biochemistry suggest altered metabolic pathways in the brain, skeletal muscles and liver. ►
M. lybicus proved relevant for evaluating the risk of pollutant exposure on human populations.
The stress profiles of the hemogram and serum biochemistry were determined in the context of heavy metal (Cd, Cu, Hg, Ni and Pb) exposure in the wild libyan jird,
Meriones libycus, from one of Riyadh’s polluted areas versus a reference site. Coupling the pronounced drop in platelets (PLT) (28%) and mean platelet volume (MPV) (17%) with the insignificant responses of other red blood cell indices, suggests bone marrow suppression that is characterized by thrombocytopenia as an initial abnormality. The species-specific stress leukogram for
M. libycus is expressed by leukocytosis (66%), monocytosis (40%), lymphocytosis (23%) with eosinopenia (81%) and neutropenia (42%). Hyperglycemia (50%), hyper-low-density-lipoproteinemia (38%), hypocortisolism (85%) and hypotriglyceridemia (55%) depicted serum biochemistry profile. In polluted jirds, the elevated activities of pseudocholinesterase (PChE) and serum marker enzymes (alanine aminotransferase ALT, aspartate aminotransferase AST and creatine kinase CK) strongly suggest functional damage of the liver and/or heart. A potential role of PChE in low-density lipoprotein (LDL) metabolism is implied in the joint rise of both indices and in the recognized relationship between PChE and lipid metabolites. While increased utilization in lipid metabolism and energy synthesis could rationalize the inhibition of the normal patterns of triglycerides and lactate dehydrogenase (LDH), the inhibited activities of LDH could additionally be attributed to its hormetic behavior towards low and high metal concentrations. The overall findings presented here documented the relevance of
M. libycus in biomonitoring and predicting the risk imposed on human populations living in polluted areas.