A New Method for Breath and Blood Alcohol Determination in Rats Using a Breath Alcohol Meter: An Experimental Study.

Background: The use of police breath alcohol detectors in rat breath alcohol detection experiments has always been a challenge because of the small lung capacity and inability of rats to actively inhale. However, the method of using gas chromatography to detect blood alcohol concentration is time-consuming, complex, relatively expensive, and cannot achieve on-site detection and multi-point unlimited non-invasive detection.

Objectives: In this study, a laboratory method was validated for rat breath ethanol concentration (BrAC) measurement to estimate blood ethanol concentration (BAC) in rats.

Methods: The rats were placed in a gas collection bottle, the breath sample was drawn out with a syringe, and injected into the mouthpiece of the breath alcohol detector through a rubber tube. The results were immediately detected and automatically converted to BAC. Male rats were randomly divided into three groups. The control group received an intraperitoneal injection of normal saline, the liver injury group received an intraperitoneal injection of 50% Carbon tetrachloride (CCL4 1 mL.kg^-1), and the induction group received an intraperitoneal injection of phenobarbital sodium (75 mg.kg^-1). Western blot analysis was used to detect the protein expression of CYP2E1. Similar grouping and experimental methods were used for female rats.

Results: This method was reproducible. The metabolic activity of CYP2E1 was downregulated in the injury group and upregulated in the induction group, which was consistent with the results obtained for CYP2E1 protein expression.

Conclusions: Our results confirmed that the rat gas cylinder breath alcohol assay can be used for multiple detections with immediate and non-invasive determination of alcohol metabolizing capacity. This is important for studies that require repeated assessment of blood alcohol levels.