Effects of ringer-acetate and ringer-dextran solutions on the microcirculation after LPS challenge: Observations in the hamster cheek pouch

The effects of NaCl 0.9%, Ringer-acetate, and Ringer-dextran given as intra venous infusions in the microcirculatory changes observed in early stages o f endotoxemia were investigated in male hamsters treated with Escherichia c oil lipopolysaccharide (LPS). The cheek pouch was studied in vivo by means of intravital microscopy. Mean arterial (MAP) and venous pressures (CVP), h eart rate, mean arteriolar internal diameter, spontaneous arteriolar vasomo tion (AV), red blood cell velocity (RBCV) in these vessels, and long-term e ffects of LPS were evaluated in animals treated with either LPS alone or th e combination of LPS with NaCl 0.9%, Ringer-acetate and Ringer-dextran. The intravenous injection of LPS (0.3 mg/kg) elicited a significant reduction in MAP and CVP, cessation of AV and a decrease in RBCV. In our study, the h eart rate and the arteriolar diameter did not change significantly, compare d with the control values obtained before the LPS injection. No improvement in the MAP could be detected with infusions of NaCl 0.9% or Ringer-acetate but the infusion of Ringer-dextran increased it significantly. All infusio ns tested maintained the CVP until the end of the observation period and th e Ringer-dextran increased it significantly. The heart rate was maintained around 360 beats/min with a tendency to decrease 70 min after the LPS infus ion in all groups studied except the group which received NaCl 0.9% where t he heart rate decreased significantly. In all the four groups, the mean art eriolar diameter did not change significantly with time during the observed period. RBCV decrease with the combination LPS + NaCl 0.9% and the infusio ns of Ringer-acetate and Ringer-dextran maintained it until the end of the observation period. The combination of LPS + NaCl 0.9% maintained the spont aneous arteriolar vasomotion during 50 min after LPS injection and the infu sion of Ringer-acetate maintained it for the 3-h observation period. The in fusion of Ringer-dextran maintained the amplitude of the spontaneous arteri olar vasomotion and increased its frequency significantly. The long-term ef fects of LPS showed weight loss and pus on the periorbital area. Our result s suggest that the best solution to maintain the microcirculatory parameter s during the early stage of endotoxemia after LPS injection was the Ringer- dextran.