title: Osteocalcin, but not deoxypyridinoline, increases in response to isoflurane-induced anaesthesia in young female guinea pigs.
abstract: The effect of the inhaled anaesthetic isoflurane was investigated on bone biomarkers, both during maturation and on minerals and glucose postpartum. Female guinea pigs (n = 10) were anaesthetized during maturation (5 and 9 weeks) and postpartum (26 weeks of age) with isoflurane during dual-energy X-ray absorptiometry scanning. Blood collection was performed at all ages before and after anaesthesia for measurement of plasma osteocalcin (OC), total deoxypyridinoline (tDPD), and cortisol. Postpartum measurements also included: blood ions, acid-base parameters and glucose, plasma minerals, total alkaline phosphatase (tALP), and albumin. Plasma OC concentration almost doubled after exposure to isoflurane at 5 weeks (30.1 ± 5.0-57.9 ± 11.2 nmol/L, p < 0.001) and at 9 weeks (29.1 ± 7.5-62.9 ± 15.9 nmol/L, p < 0.001), but did not change postpartum (3.7 ± 3.3-4.3 ± 3.9 nmol/L, p = 0.88). There was no effect of isoflurane exposure on plasma tDPD at any age. Plasma cortisol increased after exposure to isoflurane at 9 weeks (1859.6 ± 383.2-2748.0 ± 235.3 nmol/L, p < 0.01) and postpartum (3376.7 ± 322.2-4091.6 ± 195.6 nmol/L, p < 0.001) but not at 5 weeks (2088.3 ± 326.4-2464.1 ± 538.0 nmol/L, p > 0.05). Blood ionized Ca(2+), Na(+) and plasma total Ca did not change, whereas plasma albumin decreased, and inorganic phosphate (PO4) and Cl(-) increased upon exposure to isoflurane. Isoflurane decreased tALP (43.2 ± 6.6-40.2 ± 5.9 IU/L, p = 0.01) and increased glucose (7.5 ± 0.6-10.9 ± 1.7 mmol/L, p < 0.0001) postpartum. Isoflurane inflates the assessment of a bone-derived biomarker, OC, during rapid growth, but not following pregnancy when formation is very low. Measurements prior to anaesthesia are recommended to reflect normal metabolism.
authors.affiliation: School of Dietetics and Human Nutrition, Macdonald-Stewart Building Macdonald Campus, 21111 Lakeshore Road, Ste-Anne-de-Bellevue, Quebec, H9X 3V9, Canada.
authors.forename: Negar
authors.initials: N
authors.lastname: Tabatabaei
authors.forename: Celia J
authors.initials: CJ
authors.lastname: Rodd
authors.forename: Richard
authors.initials: R
authors.lastname: Kremer
authors.forename: Hope A
authors.initials: HA
authors.lastname: Weiler
mesh_terms: D000596:Amino Acids / Q000627:therapeutic use*; D000758:Anesthesia / Q000379:methods*; D000818:Animals; D000886:Anthropometry; D001823:Body Composition; D005260:Female; D006168:Guinea Pigs; D006854:Hydrocortisone / Q000097:blood; D007530:Isoflurane / Q000633:toxicity*; D015675:Osteocalcin / Q000627:therapeutic use*; D011247:Pregnancy
chemical_list: D000596:Amino Acids; D015675:Osteocalcin; C036020:deoxypyridinoline; D007530:Isoflurane; D006854:Hydrocortisone