Ika Rahma Mustika Hati, Guritno Suryokusumo, Ambar Wahyuningsih Roestam
Department of Community Medicine, Faculty of Medicine, Universitas Indonesia, Jakarta, Indonesia.
Background: Nitrox II, associated with higher oxygen partial pressure, induces an increase in reactive oxygen species, which can interfere with endothelial nitric oxide synthases (eNOSs), causing endothelial dysfunction and lower flow-mediated dilation (FMD). This study aimed to determine the influence of nitrox II on eNOS expression and FMD as markers of endothelial function. Materials and Methods: A double-blind approach was used with 39 trained male divers who were divided using randomized block design into a control group (the air group) that used compressed air or an intervention group that used nitrox II (the nitrox II group). Both the groups underwent a single decompression dive to 28 m sea water (msw) with a bottom time of 50 min in a hyperbaric chamber. Pre- and postdive eNOS expression was measured by quantitative enzyme-linked immunosorbent assay and FMD by laser Doppler flowmetry on the regio brachii. Results: eNOS (P = 0.029) and FMD (P = 0.001) decreased in the air group, whereas eNOS (P = 0.018) and FMD (P = 0,023) increased in the nitrox II group. The average difference in eNOS and FMD in the nitrox II group was greater compared with the air group (P < 0.05). There was no significant correlation between eNOS and FMD. Conclusion: Nitrox II prevents endothelial dysfunction during a single decompression dive to 28 msw with a bottom time of 50 min, as indicated by divers’ increased FMD from increased eNOS expression.
Keywords: Endothelium, endothelial nitric oxide synthase, nitrox.