IADR Abstract Archives
Endothelium-Dependent and Non-Dependent Vasodilation in Human Gingiva
Objectives: Post occlusive reactive hyperemia and the blood flow of the mucogingival flap were different between genders. However, the mechanism is unknown. We aimed to compare the endothelium-dependent (evoked by acetylcholine, ACh) and non-dependent (evoked by nitric-oxide, NO) vasodilatation between genders in the human gingiva.
Methods: Gingival blood flow of healthy young (20-30 years, mean age: 24) volunteers (N=21, female=10, male=11) was measured by laser speckle contrast imager (LSCI) and expressed in laser speckle perfusion unit (LSPU). Two wells were constructed with light cured liquid rubber-dam at the gingival sulcus of FDI#12 (test) and #21 (control) teeth. After baseline recording, 3μl 10mg/ml ACh was applied into the test well in the first session and 1mg/ml NO-donor, nitroglycerin was used in the second one. There was at least 1-week break between the two sessions. Physiological saline was applied in the control well in every measurement. The solutions were dropped with Hamilton-syringe. Four 1mm wide regions were evaluated from the gingival margin to the mucogingival line.
Results: Both solutions enhanced blood flow in every region, reaching the maximum level at 2min. The zenith of blood flow level gradually decreased apically for ACh (94±17 LSPU, p<0.01 at coronal; 83±20 LSPU, p<0.05; 69±19 LSPU, p<0.05; 60±17 LPSU, p<0.05 at apical) but not for NO (43±13 LSPU, p<0.01 at coronal;36±14 LSPU, p<0.05; 25±12 LSPU, p<0.05; 26±11 LPSU, p<0.05 at apical). The males had significantly higher blood flow elevation than females in all regions (by 45-55 LSPU, p<0.05) only after ACh but not after NO.
Conclusions: The endothelium-independent vasodilation could spread upstream (apically) in the gingiva without attenuation, contrary to the endothelium-dependent. Young females had more attenuated endothelium-dependent relaxation than males. The distinct mechanisms might explain the differences in flap microcirculation.
Methods: Gingival blood flow of healthy young (20-30 years, mean age: 24) volunteers (N=21, female=10, male=11) was measured by laser speckle contrast imager (LSCI) and expressed in laser speckle perfusion unit (LSPU). Two wells were constructed with light cured liquid rubber-dam at the gingival sulcus of FDI#12 (test) and #21 (control) teeth. After baseline recording, 3μl 10mg/ml ACh was applied into the test well in the first session and 1mg/ml NO-donor, nitroglycerin was used in the second one. There was at least 1-week break between the two sessions. Physiological saline was applied in the control well in every measurement. The solutions were dropped with Hamilton-syringe. Four 1mm wide regions were evaluated from the gingival margin to the mucogingival line.
Results: Both solutions enhanced blood flow in every region, reaching the maximum level at 2min. The zenith of blood flow level gradually decreased apically for ACh (94±17 LSPU, p<0.01 at coronal; 83±20 LSPU, p<0.05; 69±19 LSPU, p<0.05; 60±17 LPSU, p<0.05 at apical) but not for NO (43±13 LSPU, p<0.01 at coronal;36±14 LSPU, p<0.05; 25±12 LSPU, p<0.05; 26±11 LPSU, p<0.05 at apical). The males had significantly higher blood flow elevation than females in all regions (by 45-55 LSPU, p<0.05) only after ACh but not after NO.
Conclusions: The endothelium-independent vasodilation could spread upstream (apically) in the gingiva without attenuation, contrary to the endothelium-dependent. Young females had more attenuated endothelium-dependent relaxation than males. The distinct mechanisms might explain the differences in flap microcirculation.
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