Fluorochrome Bone Labeling in Sheep

Abstract

As an efficacy model. thirty-four female Merino sheep underwent transpedicular lumbar interbody fusion with three different materials for augmentation of the spine. Fluorochrome analysis was used to evaluate differences in bone deposition and fusion processes between the three study groups. During the post-operative follow-up period ofeight weeks, the fluorescent dyes xylenol orange. calcein green, and doxyeycline yellow were given at two, four. and six weeks, respectively. All dyes were administered intravenously after sedation with xylazine.
The objective of this paper is to provide a methodical description of preparation quality control, administration, efficacy, and observed adverse events from the use of these bone labels in sheep.
Both xylenol orange and calcein green dyes provided satisfying results but doxycyeline yellow led to only weak fluorescence in the first ten animals. Consequently, higher dosing was introduced to obtain bright bands in the histological sections. Also, during administration of doxycyeline yellow, mild to severe adverse events occasionally occured: Eight of the first ten sheep suffered from respiratory distress, and in severe cases several stopped breathing, thus requiring immediate intervention. Minimizing the sedative dose and elongating the sedation/doxycycline administration interval were effective changes to the original procedure. We conclude that these adverse events may have been caused by too high a close of sedative, as well as a drug interaction between xylazine and doxycycline yellow.