Urban 2017 MiP2017
Anaesthetic induction drug 2,6-propylphenol (propofol) inhibited fatty acid oxidation (FAO) and in higher concentrations decreased spare electron transfer chain (ETC) capacity in intact human skeletal muscle cells. This study aimed to use high-resolution oxygraphy in human skeletal muscle homogenate to explore the mechanism and describe the kinetics of propofol effect on key bioenergetic enzymes.
Human vastus lateralis muscle was obtained from volunteers undergoing elective hip surgery. Homogenates were prepared according to the method previously described by our research group with teflon-glass homogenizer and high-resolution respirometry (O2k-Oxygraph, Oroboros) to describe energy metabolism, using specific substrates and inhibitors of ETC, FAO was measured with the use of palmitoyl-carnitine and rotenone as inhibitor. Inhibitory effect were achieved by titrating propofol concentrations in a range from 2.5 to 100 µg/ml. Michaelis-Menten curves were constructed by titrating specific substrates for complexes I, II and FAO, with addition of defined concentration of propofol.
Inhibition of respiratory complexes and FAO is shown in Table 1. For all complexes I, II and FAO, the inhibition was of an un-competitive nature (Vmax decreased from 102.9 to 65.9, from 351.5 to 261.9 and from 93.3 to 58.3, respectively, p < 0.05; Km decreased from 0.20 to 0.15, from 1.00 to 0.80 and from 0.18 to 0.05, respectively, p < 0.05).
Acute exposure of muscle homogenate to a clinically relevant concentration of propofol leads to a non-competitive inhibition of complexes I, II and FAO. Although alternative interpretations are possible, this pattern could be explained by interaction between propofol and structurally similar Coenzyme Q.
Labels: MiParea: Respiration, Pharmacology;toxicology
Organism: Human Tissue;cell: Skeletal muscle Preparation: Homogenate
Pathway: F, N, NS HRR: Oxygraph-2k
Table 1: Inhibition of respiratory complexes and FAO, express as activity of control samples in comparison with samples with different concentration of propofol (percent ± standard deviation). Statistically significant data are highlighted, with p < 0.05.
- Urban T(1), Krajčová A(1), Kunčický P(1), Bukovský J(1), Waldauf P(1), Džupa V(2), Drahota Z(3), Duška F(1)
- OXYLAB – Lab Mitoch Physiol, Dept Anaesthesiology Intensive Care, Third Fac Med, Charles Univ
- Dept Orthopaedic Surgery, Third Fac Med, Charles Univ
- Inst Physiology, Czech Academy Sciences; Prague, Czech Republic. - [email protected]
References and support
- Ziak J, Krajcova A, Jiroutkova K, Nemcova V, Dzupa V, Duska F (2015) Assessing the function of mitochondria in cytosolic context in human skeletal muscle: Adopting high-resolution respirometry to homogenate of needle biopsy tissue samples. Mitochondrion 21:106–12.
- The work was supported by PROGRES Q37, AZV 16-28663 A.