| Abstrakt: |
The effects of sepsis on intracellular Na+ activity, Na+ concentration, and H2O partition in skeletal muscle were investigated in a burn rat model. Studies were performed on either postburn day 3 or day 7 during evolving burn wound sepsis. Data are compared among 3 groups of rats: burned and infected (BI), burned not infected (B), and sham burn (C). After 3 days postburn both Na+ activity and concentration decreased in the BI group as compared with B and C groups. By postburn day 7, the BI group developed septic shock and had increased intracellular Na+ activity and concentration. The resting membrane potentials of skeletal muscle cells depolarized. The finding of an increased cell membrane relative permeability of Na+ to K+ could account for the increase in Na+ influx into cells. In addition, intracellular and total muscle H2O contents decreased and extracellular H2O increased. Hypernatremia, hyperchloremia, and hyperosmolality were also observed in the BI group. However, the fact that there was no significant difference between B and C groups indicates that the late derangements were due to septic shock rather than simple burn injury. Thus, the deleterious effects of the evolving burn wound sepsis on Na+ homeostasis might be due to the detrimental effect of increased intracellular Na+ activity on mitochondrial respiratory control with subsequent impairment of cellular functions. |
