Objective: To investigate the effect of chronic intermittent hypoxia (CIH) on mitochondrial function in genioglossus cells of rats and intervention role of adiponectin (Ad).
Methods: Thirty-nine healthy male Wistar rats were randomly divided into 3 groups, normal control (NC) group, CIH group and CIH + Ad group with 13 rats in each. Rats in NC group were kept breathing normal air, while rats in both CIH and CIH + Ad groups experienced the same CIH environment (CIH 8 h/day for successive 5 weeks). However, rats in CIH + Ad group was given intravenous Ad supplement at the dosage of 10 µg, twice a week for successive 5 weeks. At the end of experiment (day 35), the levels of plasma adiponectin, mitochondrial membrane potential activities of respiratory chain complexes I and IV in mitochondrion of genioglossus cells were compared among different groups.
Results: Serum Ad level was significantly lower in CIH group than that in NC group [(1108 ± 112) ng/ml vs (2241 ± 121) ng/ml, P < 0.01]. Serum Ad level in CIH + Ad group [(1889 ± 119) ng/ml] was significantly higher than that in NC group but lower than that in CIH group (all P < 0.01). Mitochondrial membrane potential was significantly lower in CIH group than that in NC group [(1.82 ± 0.11) vs (2.09 ± 0.14), P < 0.01]. Mitochondrial membrane potential in CIH + Ad group (1.98 ± 0.09) was higher than that in CIH group but lower than that in NC group (all P < 0.05). The concentrations of mitochondrial respiratory chain complexes I and IV in CIH group (35.68 ± 1.73) µmol×min(-1)×mg(-1) and (2.37 ± 0.11) nmol×min(-1)×mg(-1), respectively) were the lowest but became higher from CIH + Ad group [(37.18 ± 1.95) µmol×min(-1)×mg(-1) and (2.49 ± 0.09) nmol×min(-1)×mg(-1), respectively] to NC group (39.02 ± 1.38) µmol×min(-1)×mg(-1) and (2.81 ± 0.12) nmol×min(-1)×mg(-1), respectively), with a significant difference between NC and CIH groups (P < 0.01), between CIH + Ad and CIH groups (P < 0.05), as well as between CIH + Ad and NC groups (P < 0.05).
Conclusion: CIH could lead to hypoadiponectinemia and impaired mitochondrial function in genioglossus cells of rats. Since such changes could be partially improved by supplement of adiponectin, it was suggested that hypoadiponectinemia might be involved in CIH-induced impairment of genioglossus energy metabolism.