Protective effect of polyurethane immobilized human butyrylcholinesterase against parathion inhalation in rat.

Organophosphates (OP) are used in large quantities around the world as agricultural insecticides. Exposure to these toxic chemicals is a serious global health problem. Human plasma butyrylcholinesterase is known to be a good scavenger of organophosphorus pesticides and chemical warfare agents. In this study, purified human plasma butyrylcholinesterase (HuBChE) from pooled outdated human plasma, was immobilized onto the polyurethane foam. The immobilized enzyme showed greater stability at and above room temperature (up to 55°C), compared to the enzyme in solution. Scavenger properties of immobilized enzyme were tested in vitro with parathion and its active metabolite paraoxon. In, in vitro experiments polyurethane foam with immobilized active enzyme removed 40% of parathion and 50% of paraoxon inhibitory effect (based on cholinesterase inhibition). In, in vivo experiments groups of rats inhaled parathion through filters with immobilized active enzyme (Group I), immobilized inactivated enzyme (Group II), and control group (Group III) inhaled solvent only without any parathion or filter. In the Group II animals, activity of plasma and red blood cells cholinesterase was significantly decreased (30 and 28%, respectively) compared to Groups I and III animals. In other tissues such as brain, skeletal muscle and lung, activity of the acetylcholinesterase (AChE) in the Group II animals, was decreased significantly (29, 28, and 22%, respectively). There was no significant differences between Groups I and III animals enzyme activities. In conclusion, immobilized butyrylcholinesterase (BChE) may be useful in scavenging and detoxifying organophosphate compounds both for medical protection and decontamination procedures.