Proceedings of The Physiological Society
University of Oxford (2011) Proc Physiol Soc 23, PC228
Influence of hyperbaric oxygen treatment on cerebral resistance vessels reactivity in diabetic rats
S. Unfirer1, M. Gros1, I. Drenjančević1
1. Department of Physiology and Immunology, Faculty of Medicine University of Josip Juraj Strossmayer in Osijek, Osijek, Croatia.
The incidence and mortality of ischemic stroke is higher in diabetic patients compared with non-diabetic patients (1). Previous studies on diabetic animal models as well as in humans confirmed that vascular reactivity to various stimuli in diabetes mellitus is significantly impaired (2, 3). The aim of this study was to evaluate the effects of hyperbaric oxygen treatment (HBOT) on vascular reactivity in response to several vasoactive stimuli, in isolated, pressurized and perfused middle cerebral arteries of Sprague-Dawley (SD) male rats by videomicrometry. There were four groups of rats; control (n=12); diabetic (n=12); diabetic (n=11) and control (n=12) rats that underwent HBOT . Rats were exposed to HBOT at 2,0 atm, for a duration of 120 minutes for 4 consecutive days. Diabetes was induced at 6 weeks of age by a single dose of streptozocin (60mg/kg i.p.). Rats were 12 weeks-old at the time of the experiment. For statistical analysis One way ANOVA was performed (Sigma Plot 11.0). Results showed significantly decreased vasodilation in response to hypoxia (p<0,001) and acetylcholine (Ach 10-6 mol/l) (p< 0,014) in diabetic group compared to all other groups, and restored vasodilation in response to ACh and hypoxia in diabetic rats after HBOT compared to diabetic group. Vasodilatation in response to NO donor DEA-NONO-ate (10-6 mol/l) (p=0,931) was not significantly different among groups, suggesting that during 6 weeks of DM vascular smooth muscle cells kept their ability to respond to NO by relaxation. Vascular response to vasoconstrictor serotonin (10-6 mol/l) (p=0,983) was not significantly different among groups. In conclusion, our results demonstrate that hyperbaric oxygen treatment leads to restoration of vasodilation in response to ACh, but does not enhance vasoconstriction in response to serotonin, suggesting a beneficial effect of HBOT on vascular function and tissue perfusion.
Where applicable, experiments conform with Society ethical requirements