Effects of Acute Inhalation Exposure to Refrigerants R-22, R-134a and R-410A on Biochemical Parameters in Wistar Rats

Abstract

Background: Refrigerants R-22, R-134a and R-410A may result in inhalation exposure during maintenance or accidental leaks, but their early biochemical effects remain insufficiently characterised. This study evaluated glucose, lipid and renal parameters in Wistar rats after acute exposure. Materials and Methods: Forty-eight rats (24 males and 24 females) were allocated to three refrigerant groups, with a model-derived equivalent dose of 487.95 mg/kg for 1 h. The analysis comprised 12 controls and 36 exposed rats sampled at 0, 1 or 24 h. Biochemical parameters were measured on a COBAS c311 analyser. Non-parametric tests, Benjamini–Hochberg adjustment, Hedges' g and Cochran's test were applied. Results: Distinct clinical responses were observed, including narcotic-like signs under R-22, marked agitation under R-134a and an intermediate response under R-410A, with no mortality at the planned exposure dose. After adjustment, no biochemical difference between exposed and control animals remained significant (adjusted p ≥ 0.902). Glucose increased under R-22 (122.5 to 157.5 mg/dL; g = 1.99) but decreased under R-134a (111.5 to 74.5 mg/dL; g = −1.99), and glycaemic responses differed across refrigerants (Q = 10.07; p = 0.007; I² = 80%). Lipid parameters remained broadly stable, whereas creatinine showed a moderate pooled effect (g = 0.63). Weight loss did not exceed 2.2%. Conclusion: Statistical analyses revealed no significant overall biochemical difference between the exposed and control groups after adjustment; nevertheless, the divergent glycaemic responses suggest refrigerant-specific patterns that warrant further investigation before any causal conclusion can be drawn.