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Changes in perimicrovascular protein spatial distribution due to superfusate
B J Barber1, S Dutta, S Parameswaran
1Center for Biomedical Engineering, University of Kentucky, Lexington 40506-0070, USA.
Objective:
To determine superfusate-induced changes in the distribution of plasma proteins in the perimicrovascular interstitial matrix.
Methods:
Rats were anesthetized with sodium pentobarbital and a mesenteric loop was exteriorized. Intravital video microspectrophotometry was performed using wavelengths of 280, 320, and 700 nm. The images were analyzed to give protein and collagen spatial distributions in vascular regions of rat mesenteric tissue. Perimicrovascular protein concentrations were fitted to an exponential decay model ci + cr exp (-x/k), where ci is distal protein concentration, ci + cr is the protein concentration proximal to the vessel, x is the distance from the vessel wall, and k is the decay constant indicating protein gradient slope.
Results:
Before superfusion with 0.5-ml normal saline, ci = 1.45 +/- 0.13 g/dl, ci + cr = 4.56 +/- 0.23 g/dl. After the first superfusion, ci decreased (p < 0.01) to 0.53 +/- 0.06 g/dl; following a second superfusion, cr decreased to 0.4 +/- 0.03 g/dl; an additional final superfusion caused a further decrease to 0.33 +/- 0.02 g/dl. ci + cr also decreased significantly during repeated superfusions to 2.92 +/- 0.15, 2.35 +/- 0.25, and 2.1 +/- 0.12 g/dl, respectively.
Conclusions:
Superfusion produced changes in perivascular and distal interstitial matrix protein distribution. Protein concentration proximal to the microvessel remained higher than distal concentrations. This could be due to increased gel concentrations inhibiting protein mobility.
Insights
Superfusion significantly altered plasma protein distribution in the interstitial matrix. Protein concentrations near microvessels decreased, suggesting changes in interstitial gel properties affect protein mobility.
Area of Science:
- Physiology
- Biophysics
- Microcirculation Research
Background:
- The interstitial matrix surrounding microvessels plays a crucial role in regulating fluid and solute exchange.
- Understanding protein distribution within this matrix is essential for comprehending microvascular function and disease pathogenesis.
Purpose of the Study:
- To investigate the impact of superfusion on plasma protein distribution within the perimicrovascular interstitial matrix.
- To quantify changes in protein concentration gradients in response to superfusion.
Main Methods:
- Intravital video microspectrophotometry was employed in anesthetized rats with exteriorized mesenteric loops.
- Analysis focused on spatial distribution of proteins and collagen using specific wavelengths.
- Perimicrovascular protein concentrations were modeled using an exponential decay function.
Main Results:
- Superfusion with normal saline significantly decreased distal protein concentration (ci) and proximal protein concentration (ci + cr).
- Repeated superfusions led to progressive reductions in both ci and ci + cr, indicating a dose-dependent effect.
- Protein concentration remained higher near the microvessel wall compared to distal regions even after superfusion.
Conclusions:
- Superfusion alters plasma protein distribution in the perimicrovascular interstitial matrix.
- The persistent higher protein concentration near the microvessel suggests increased interstitial gel concentration may impede protein mobility.