Effect of time and storage temperature on cholinesterase activity in blood from normal and organophosphorus insecticide-treated horses.

This study examines the impact of time and storage temperature on cholinesterase activity in horse blood, finding that blood from normal or organophosphate-treated horses can be used for cholinesterase evaluation for up to a week when stored at 5 C.

Research Methods and Participants

• The research was carried out on 22 horses in total. Six of these were treated with trichlorfon, an organophosphorus insecticide, six with dichlorvos, another organophosphorus insecticide, and ten were left untreated to act as control subjects.
• The study was designed to examine the effects of delays between blood sample collection and testing, which is a common practical concern in clinical testing.

Measurement of Cholinesterase Activity

• The cholinesterase activity in the blood of each horse was measured using an adaptation of the Ellman colorimetric method, a widely accepted technique used to measure the cholinergic activity.
• After the initial cholinesterase activity was recorded, the blood from every horse was split into three groups and stored at different temperatures: 5 C (refrigerated), 20 C (room temperature), or 38 C (incubated).

Results and Implications

• For the untreated horses as well as the trichlorfon-treated horses, the cholinesterase activities did not significantly increase or decrease after up to 1 week or 4 weeks respectively, for all temperature conditions.
• For dichlorvos-treated horses, a significant increase in cholinesterase activities was recorded after 1 week for refrigerated samples and 24 hours for room temperature and incubated blood samples.
• The implications of the findings are that blood from normal or organophosphate-treated horses can be reliably used for cholinesterase evaluation for up to one week when stored at 5 C (41 F). The study’s results can optimize the handling and storage of equine blood samples for cholinesterase activity evaluation, particularly in clinical situations that involve exposure to organophosphorus pesticides or nerve gas agents.