Effect of Sex, Anesthesia Method, Physiological Asymmetry, and Strain on Rat Lymphatic Vessel Contractility Assessed...

This study aims to investigate the effect of sex, anesthesia administration method, lymphatic physiological asymmetry, and strain on popliteal lymphatic collecting vessel contractile function and transport in effort to create a research comparison standard for experimentations using rat popliteal lymphatics.

Naïve female and male (8-10 weeks old) Sprague-Dawley and Lewis rats (both left and right hind limbs) under two forms of anesthesia administration (ketathesia/dexdomitor and isoflurane) were used to assess lymphatic contractility and transport function via near-infrared imaging and linear mixed-effects modeling.

We quantified lymphatic contractility and transport through five functional metrics (packet frequency, packet amplitude, normalized packet transport, packet width, and normalized packet integral) via near-infrared imaging and found that both sex and anesthesia method significantly affect pumping behavior, while physiological asymmetry had minimal influence. Additionally, we identified strain-dependent differences in contractile dynamics between Sprague Dawley and Lewis rats. Linear mixed-effects modeling further supported these results, highlighting the significant and differential roles that sex, anesthesia method, and strain play in modulating lymphatic contractile function.

Our results showcase that to create standard comparison criteria for rat popliteal lymphatic models, one consistent method of anesthesia is essential and for sex to be considered as a biological variable. These findings underscore the physiological variability that must be accounted for when modeling lymphatic function and disease.