Figure 1.
A schematic overview of the experiment flow is shown in the figure. The investigation consisted of an initial lactic acid load to induce lactic acidemia followed by randomization to sustained (S) or transient (T) lactic acid infusion with or without sodium bicarbonate (B) treatment.
Figure 2.
Lactate over time in the four groups.
Lactic acid load caused blood lactate to rise in all groups (# P<0.05 vs. time 0). After 135 minutes in the sustained groups blood lactate remained high both in the sustained (S) and the sustained+NaHCO3 (S+B) group. In the transient (T) groups blood lactate levels after 135 minutes were different from values at time 75 minutes (° P<0.05). Animals that received NaHCO3 (T+B) had higher lactate levels (* P<0.05 vs. transient group).
Figure 3.
Blood pH over time in the four groups.
After 75 minutes of infusion of lactic acid blood pH drop in all groups (# P<0.05 vs. time 0). At 135 minutes pH normalized in the transient group (T) while overshoot to alkalemic values when animals received NaHCO3 (T+B). In the sustained group (S) pH continued to drop while alkaline infusion (S+B) resulted in correction of acidosis. ° P<0.05 vs time 75; * P<0.05 vs. control.
Table 1.
Acid base variables and plasma chemistry.
Table 2.
Hemodynamic and respiratory variables.
Table 3.
Lactate pharmacokinetics.
Figure 4.
Blood lactate and blood glucose decrease in transient lactic acid infusion group.
Decrease over time of blood lactate concentration and glycaemia in the animals with transient lactic acid infusion. Values are expressed as percentage decrease from time 75 to 135 (*P<0.05 vs. transient group).
Figure 5.
Activity of the glycolytic enzyme phosphofructokinase (PFK) in the glycolitic muscle (ME- extensor digitorum longus) was slightly higher when bicarbonate was infused (P = 0.067). Ctrl = end of lactic acid infusion (i.e 75′ after the start of acid load).