Significant increase in plasma osteocalcin in response to isoflurane induced anaesthesia in guinea pigs

Abstract

The effect of the inhaled anaesthetic, isoflurane was studied on osteocalcin (OC) and total deoxypyridinoline (tDPD) in pigmented guinea pigs. Ten female guinea pigs were anaesthetized at five and nine weeks of age with isoflurane. The duration of anaesthesia was similar (20–25 min) in all guinea pigs across both age. Blood samples were collected at both time points, before and after the induction of the anaesthesia. Osteocalcin and tDPD were measured using ELISA (Quidel Corp.). Osteocalcin concentration increased due to isoflurane from 30.1±4.9 to 57.9±11.2 nmol/L (p<0.001) and from 29.1±7.5 to 62.9±15.9 nmol/L (p<0.001), at five and nine weeks of age, respectively. The effect of isoflurane on tDPD was inconsistent for the fifth and ninth week of age. Isoflurane increased tDPD (8.6±1.9 to 10.3±3.0 nmol/L) at five week of age while it decreased it (12.3±4.0 to 10.5±1.7 nmol/L) at nine week of age. The results demonstrate that administration of isoflurane changes both OC and tDPD. Therefore the interpretation of results obtained from animals anaesthetised by isoflurane on bone biomarkers should be made with caution since they may be highlighted or masked by the effect of the anaesthetic. Measurements prior to anaesthesia are recommended for better consistency and comparability in research. This study was funded by CIHR.