Effects Of Acute Hypoxic Stress And Acetazolamide Intervention On Mice Major Organs And Tissues Blood Flow Measured By Color Microsphere Method

Objective: To observe the effects of acute hypoxic stress on relative blood flow in organs and tissues of mice and the intervention of acetazolamide(AZ)study.Methods: BALB/c mice were randomly divided into normoxia control(NC),15% O2 hypoxia control(HC),normoxia +AZ(NA)and hypoxia +AZ(HA)groups(each group n=8).The NA and HA groups were given acetazolamide by intragastric administration(100mg/kg,0.2m L).NC and HC groups were given equal volume saline.The polyethylene catheter(ID 0.3 mm,OD 0.5 mm)was introduced into the left ventricle via the right cephalic artery to inject yellow and red microspheres solution during 1 min and 3 min ventilation respectively.The microspheres were recovered from the brain,heart,lung,liver and kidneys of mice,and OD values from microspheres were measured to calculate the relative blood flow of each organ and tissues.Take another group of mice,arterial blood samples were collected before hypoxia and during hypoxic ventilation 1 min and 3 min to measure blood gas for p H,Pa O2 and Sa O2.The concentration of serum ?-Enkephalin(?-Ep),Angiotensin ?(Ang ?)and Catecholamine(CA)were measured by ELISA kits.Results:(1)Blood flow result: The blood flow of organs and tissues measured in 3 min was lower than that in 1min(except pulmonary nutrient vascular blood flow in HC group),but the trend of blood flow of each group was nearly the same.During acute hypoxic stress,the cerebral blood flow(CBF)and renal blood flow(RBF)were increased while hepatic blood flow(HBF)was decreased in HC group compared with the NC group(P < 0.05).After AZ intervention,In NA group,the CBF,RBF,HBF and myocardial blood flow(MBF)higher than NC group(P < 0.05).Compared with the NA group,the HBF and MBF were decreased in HA group(P < 0.05).Compared with the HC group,the CBF and HBF were increased in HA group(P < 0.05).(2)The decrease of pulmonary nutrient vascular blood flow(PBF)from 1 min to 3 min in HA group was higher than that in HC group(P < 0.05),there was no significant difference in other groups(P > 0.05).(3)Blood gas result: Compared with the normoxia control group,the parameters of PO2,Sa O2 were decreased(P < 0.05),while p H was no significantly in 1min,3 min hypoxia ventilation(P > 0.05).(4)The Catecholamine(CA)levels in serum of mice increased during 15% O2 hypoxia ventilation(P < 0.05).After AZ intervention,?-Endorphin(?-Ep),Angiotensin ?(Ang ?)and CA of HA group increased compare with NA group,but CA was lower than HC group(P < 0.05).Conclusion: Acute hypoxia stress can be compensated for readjustment of blood flow distribution in mice organs and tissues,the CBF and RBF were increased while HBF was decreased.Acetazolamide could increase CBF,MBF,HBF and RBF in normoxia condition.The co-effect of acute hypoxic stress and acetazolamide may increase CBF.Hypoxic stress may inhibit acetazolamide in increasing blood flow in the HBF.Acute hypoxic stress can increase CA in serum of mice but AZ may inhibit the level of CA in hypoxia.In addition,AZ may improve ?-Ep,Ang ? level in serum of mice during hypoxic stress.