Identification and Evaluation of Chronic Low-Level Pb Toxicity Biomarkers in Neonatal Rats
Rajvee Parikh, St. John’s University Student
Marc E. Gillespie, Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences
Abstract: The deleterious health effects of environmental Pb exposure have been observed and documented in numerous populations. Children, in particular, are very vulnerable to Pb toxicity. At the protein level, Pb substitutes for polyvalent cations, such as Ca2+. In proteins that bind Ca2+ for their function, this Pb substitution can interfere with the function of the protein.
The focus of our research is the evaluation of molecular biomarkers that can be used as a diagnostic of chronic low-level toxicity. In order to identify valid molecular makers we have focused on a more complex model system comprised of neonatal and maternal Long evans rats. Animals were divided into four treatment groups (n=4/group) with each group exposed to Pb acetate via drinking water ad libitum. After parturition the pups continued receiving Pb through lactating mothers. Pups were sacrificed on PND 35 and brains were dissected out for further biochemical analysis. Blood Pb levels in each pup were confirmed by the ICP atomic emission spectroscopy. Two treatment groups showed delayed parturition and a decreased number of pups as compared to untreated control. This effect was significant in higher concentrations of Pb. The pups receiving the highest concentration of Pb showed a decreased rate of development as compared to the control.
Previous toxicoproteomic work in our lab had identified the neuronal SNARE (Soluble NSF Attachment protein Receptor) proteins as molecular targets of low-level Pb intoxication. The neuronal SNARE proteins SNAP-25, Synaptobrevin, and Syntaxin are vital components of the vesicular neurotransmitter release machinery. Using our animal model system the SNAREs and associated proteins were evaluated. Protein expression patterns were characterized and evaluated using traditional western gel analysis. Gene expression patterns were characterized with RT-PCR and microarray analysis.