Objective: To investigate the effect of SOD and NaHCO3 on the vascular hyporeactivity after severe hemorrhagic shock in rats.
Methods: Twenty eight Sprague-Dawley rats were divided randomly into 4 groups of 7 each: SOD-treated group, NaHCO3-treated group, SOD+NaHCO3-treated group and normal saline-treated control group. The responses of arterioles to norepinephrine (NE), the effects of dopamine on blood pressure, blood flow velocity in arterioles, the mean arterial pressure (MAP), and the survival time within 24 h were measured.
Results: Two hours after shock, the arteriolar vasoreactivity was significantly reduced and threshold concentration of NE was increased by 24 to 27 folds. After beting treated separately with SOD, NaHCO3 and SOD+NaHCO3, arteriolar vasoreactivity was restored to some extent, among which the SOD+NaHCO3 group obtained a most significant effect with decreased threshold concentration of NE to 21% of its normal level. In SOD+NaHCO3-treated group, injection of dopamine indicated a most significant effect on MAP with 1.9 times more than that in control group, and the enhanced MAP was maintained at a level of more than 13.33 kPa after reinfusion of shed blood. The blood flow in arteriole was 2.54-fold higher than that in control group after 2 h resuscitation. The average survival time in SOD+NaHCO3- treated group was 2.9 times longer than that in control group.
Conclusions: SOD and NaHCO3 could both recover the lower vasoreactivity and increase the enhancing effect of dopamine on blood pressure of rats in severe hemorrhagic shock, suggesting that coadministration of SOD and NaHCO3 could be a new approach to the treatment of severe hemorrhagic shock.