Capillary Red Blood Cell Velocity Is Decreased in Skeletal Muscle of Septic Rats: In Vivo Imaging Using...

Area of Science:

• Physiology
• Pathophysiology
• Microcirculation

Background:

• Sepsis is a life-threatening condition characterized by a dysregulated host response to infection.
• Microcirculatory dysfunction, including altered red blood cell (RBC) flow, is a hallmark of sepsis.
• Understanding sepsis-induced changes in skeletal muscle microcirculation is crucial for patient outcomes.

Purpose of the Study:

• To investigate the impact of sepsis on red blood cell velocity, capillary diameter, and capillary flow categories in skeletal muscle.
• To analyze microcirculatory changes in the spinotrapezius muscle of rats 3-4 hours after sepsis induction.

Main Methods:

• Male Wistar rats underwent either cecal ligation and perforation (CLP) to induce sepsis or a sham procedure.
• In vivo stain-free videocapillaroscopy was used to image capillaries in the spinotrapezius muscle.
• Red blood cell velocity, capillary diameter, and capillary flow categories (continuous, intermittent, stopped) were analyzed.

Main Results:

• Sepsis significantly decreased red blood cell velocity in skeletal muscle capillaries compared to the sham group (p=0.01).
• No significant differences were observed in capillary diameter or the proportion of capillaries in each flow category between the sepsis and sham groups.
• A trend towards a negative correlation between capillary diameter and RBC velocity was noted in the sepsis group (r²=0.16, p=0.08).

Conclusions:

• Sepsis leads to a reduction in red blood cell velocity within resting skeletal muscle capillaries.
• Sepsis does not significantly alter skeletal muscle capillary diameter or the classification of capillary flow patterns in the early stages.
• These findings highlight early microcirculatory impairment in skeletal muscle during sepsis.