Abstract:

Objective To establish a noninvasive method of ¹³C-glucose breath test in assessment of insulin resistance (IR) based on the diabetic mice models, and explore its correlation with the other IR indexes. Methods Diabetic mice models were established by intravenous injection of alloxan tetrahydrate. For the ¹³C-glucose breath test, samples were collected at various time points after ingestion of 5 mg/kg ¹³C-labelled glucose. The value of ¹³CO₂ at 90 min (C90 min) was calculated as the parameter of IR, and the effect of exogenous insulin (1 U) intervention on diabetic mice was evaluated. Fasting blood glucose and fasting insulin of diabetic mice were measured, and homeostatic model assessment of insulin resistance (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI) were calculated. The correlation of C90 min with HOMAIR or QUICKI was analysed.ResultsC90 min in diabetic mice was significantly lower than that in normal rats [(0.79±0.18)% vs (1.19±0.31)%, t=2.470, P<0.05]. C90 min in diabetic mice increased to (1.17± 0.25)% after exogenous insulin (1 U) intervention (t=－2.522, P<0.05). Correlation analysis revealed that C90 min was well related to HOMA-IR (r=-0.64, P<0.05) or QUICKI (r=0.88, P<0.01). Conclusion ¹³C-glucose breath test may provide an effective noninvasive method for the assessment of IR in diabetic mice, which is well related to the IR indexes clinically available.

Key words: ¹³C-glucose, breath test, insulin resistance, diabetic mice