The effect of cryotherapy on the cremaster muscle microcirculation in vivo

Abstract

Summary The effect of cryotherapy on normal striated muscle was investigated using 18 adult male rats. Animals were divided into two groups, an experimental cryotherapy group and a control group receiving sham treatment. After the surgical procedure animals were allowed to equilibrate and vessel diameters, macromolecular leakage and blood flow were assessed before the cremaster muscle was frozen to -60°C. After thawing measurements were taken every 15 min over a 2 h period. Cryotherapy resulted in an initial reduction in blood flow followed by a brief period of reperfusion, with complete vascular stasis eventually observed. Macromolecular leakage occurred from all vessels, which mirrored the fluctuations in blood flow. Transient changes in vessel diameters were also observed. Histology confirmed the in vivo observations of vessel congestion and muscle damage. The data suggest that cessation of flow and increased macromolecular leakage within the muscle may contribute to the cell death and tumour necrosis observed following cryotherapy.

Leucocyte interactions with the mouse cremaster muscle microcirculation in vivo in response to tumour-conditioned medium

“…The technique of in vivo microscopy permits dynamic visualization of the microcirculation (Reed et al, 1989;Brown et al, 1994a) and of the ex vivo fluorescently labelled LAK cells and host leucocytes moving through the microcirculation, migrating across the endothelium and basement membrane and localizing within the tumour (Sasaki et al, 1991;Brown et al, 1994b). This is therefore an effective method for monitoring cell trafficking in vivo.…”

Epi–Illumination Fluorescent Light Microscopy for The In Vivo Study of Rat Hepatic Microvascular Response to Cryothermia

“…This is not in disagreement with the results obtained from the studies in the cremaster muscle, because the short period of reperfusion after thawing was documented only in larger arterioles and venules, while complete reperfusion deficits were observed in capillaries as well as postcapillary venules at any time point of the 2-hour observation period after thawing. 21 The blood flow observed in the larger arterioles and venules of the cremaster muscle may, thus, just have been maintained by arterio-venous shunting. Our results are also consistent with the laser Doppler flowmetry measurements of red cell flux in the normal rat liver, which have demonstrated complete failure of blood flow immediately after freezing, with almost no recovery during an 8-hour observation period.…”

“…21 In hepatic tissue, we have shown herein that freezing to temperatures below Ϫ60°C results in an immediate and complete shutdown of sinusoidal perfusion, i.e., nutritive hepatic blood supply, without any recovery during a 2-hour observation period. This is not in disagreement with the results obtained from the studies in the cremaster muscle, because the short period of reperfusion after thawing was documented only in larger arterioles and venules, while complete reperfusion deficits were observed in capillaries as well as postcapillary venules at any time point of the 2-hour observation period after thawing.…”

“…In contrast, intravital microscopy represents a sophisticated technique, which allows direct in vivo visualization of the microvasculature, 19 and provides the potential to study cellular and molecular mechanisms of microvascular dysfunction. 20 Consequently, Brown et al 21 added a second study on …”

“…In contrast, intravital microscopy represents a sophisticated technique, which allows direct in vivo visualization of the microvasculature, 19 and provides the potential to study cellular and molecular mechanisms of microvascular dysfunction. 20 Consequently, Brown et al 21 added a second study on the effects of cryotherapy using intravital fluorescence microscopy to their previous study on the effects of cryotherapy on liver blood flow performed by laser Doppler flowmetry. This study, however, which demonstrates cryothermia-induced selective vasoconstriction, increase of microvascular permeability, and, finally, shutdown of the microcirculation, was performed in the cremaster muscle, but not in living hepatic tissue.…”