Abstract
Objective
To assess the effects of xylazine and dexmedetomidine on equine chondrocytes,
in vitro
.
Study design
Prospective, experimental study.
Study material
Equine articular chondrocytes from five male horses.
Methods
Chondrocytes were isolated from healthy equine articular cartilage of the metacarpo/metatarsophalangeal joints. Cell viability was assessed using the WST-8 assay by exposing chondrocytes to xylazine (0.5, 1, 2, 4, 8, 16.6, 25, 50 mg mL
−1
) or dexmedetomidine (0.001, 0.005, 0.01, 0.05, 0.175, 0.25 mg mL
−1
) for 15, 30 and 60 minutes. Based on the results of these tests, cells were treated with xylazine (1, 4, 25 mg mL
−1
) or dexmedetomidine (0.05, 0.175, 0.25 mg mL
−1
) for 15 minutes to further evaluate: cell viability by neutral red uptake; cell membrane integrity by lactate dehydrogenase release and by fluorescence microscopy with Hoechst 33342 and propidium iodide (PI), and apoptosis by flow cytometry using double staining with annexin V-fluorescein isothiocyanate/PI and by cell morphology.
Results
Both drugs reduced cell viability in a dose-dependent manner. Specifically, all xylazine concentrations, except 0.5 mg mL
−1
and 1 mg mL
−1
, significantly reduced cell viability, whereas the effects of dexmedetomidine were evident only at 0.175 mg mL
−1
and 0.25 mg mL
−1
. The highest concentrations of xylazine (25 mg mL
−1
) and dexmedetomidine (0.25 mg mL
−1
) caused loss of membrane integrity. Cell morphology and flow cytometry analyses demonstrated signs of late apoptosis in xylazine-treated cells, and signs of late apoptosis and necrosis in dexmedetomidine-treated cells.
Conclusions and clinical relevance
This study offers new insights into the potential chondrotoxicity induced by dexmedetomidine and xylazine. Therefore, the intra-articular administration of α
2
-agonists should be conducted with care, especially for doses of ≥ 4 mg mL
−1
of xylazine and 0.175 mg mL
−1
and 0.25 mg mL
−1
of dexmedetomidine.
Page:
295-295
Related
Batch download
Cited By
noting
Similar Literature
Submit Feedback
Please wait while the file you selected is being converted