Effects of some anesthetic agents on skin microcirculation evaluated by laser Doppler perfusion imaging in mice

Abstract

Background: Anesthetic agents alter microcirculation, influencing tissue oxygenation and delivery of vital substrates. Laser Doppler perfusion imaging is a widespread technique in the field of microvascular research that can evaluate noninvasively and in real time the effects of environmental conditions, physical manipulations, diseases and treatments on peripheral perfusion. This study aims to evaluate laser Doppler perfusion imaging as a means to detect changes in skin microcirculation induced by some popular anesthetic agents in a murine model. Twenty-four age- and gender-matched healthy CD1 mice were examined by laser Doppler perfusion imaging. The skin microcirculatory response was measured at the level of plantar surfaces during isoflurane anesthesia with or without subsequent dexmedetomidine or acepromazine. At the end of the procedure, dexmedetomidine was reversed by atipamezole administration.

Results: In all mice, skin blood flow under isoflurane anesthesia did not show significant differences over time (P = 0.1). The serial perfusion pattern and values following acepromazine or dexmedetomidine administration differed significantly (P < 0.05).

Conclusions: We standardized a reliable laser Doppler perfusion imaging protocol to non-invasively assess changes in skin microcirculation induced by anesthesia in mice, considering the advantages and drawbacks of this technique and its translational value.

Figure 1

LDPI scan technique. (A) Animal positioning in sternal recumbency on a light-absorbing pad, with the hind plantar surfaces symmetrical and perpendicular to the laser beam. (B) LDPI image post-processing and measurement standardized protocol: the mean intensity of the Doppler signal was registered in ROI encompassing the hind paws and expressed as numerical value normalized for their area (perfusion color scale 0–5 volts).

Figure 2

Representative LDPI images. Peripheral perfusion patterns in mice over time after administration of 3 anesthetic protocols. Time points with significant differences (P < 0.05) are reported. Group 1 (top row) 10 (A) and 20 minutes after acepromazine injection (B); group 2 (middle row) 5 (C) and 15 minutes after dexmedetomidine injection (D) and 5 minutes after atipamezole administration (E); control group (lower row) 10 (F), 20 (G) and 30 minutes after isoflurane maintenance (H) (perfusion color scale 0–5 volts as reported in Figure 1).