Gilday Rebecca, Richard Hélène, Beauchamp Guy, Fogarty Ursula, Laverty Sheila
Comparative Orthopaedic Research Laboratory, Département des Sciences Cliniques, Faculté de Médecine Vétérinaire, Université de Montréal, St-Hyacinthe, Quebec, Canada.
Département de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, St-Hyacinthe, Quebec, Canada.
Equine Vet J. 2020 Sep;52(5):733-742. doi: 10.1111/evj.13235. Epub 2020 Feb 21.
The administration of bisphosphonate medications, which target osteoclastic-bone remodelling, to juvenile and adult racehorses is a matter of debate owing to concerns that these molecules remain bound to the bone-mineralised matrix and may interfere with subsequent bone growth, adaptation to exercise and healing of bone microdamage in equine athletes. Osteoclasts participate in endochondral ossification, subchondral bone remodelling and bone repair. There is a knowledge gap on the role of equine osteoclast biology in the growth and maturation of joint surfaces and this information is important to inform judicious bisphosphonate use.
Measure and compare the osteoclast density in the subchondral bone of Thoroughbred (TB) distal third metacarpi (McIII) at different sites, varying depths from the articular surface and with age (0-84 months).
Ex vivo cadaveric study.
McIIIs from foals, yearlings and adults were collected, fixed in formaldehyde and stored at 4°C. Sections were cut from the lateral hemi-metacarpus, stained and scored for cartilage degeneration. Osteoclasts were counted on immunohistochemically (Cathepsin K) stained sections. Osteoclast density was compared in regions of interest (ROIs-the sagittal ridge, axial and abaxial condyle) and also at two depths (0-3 mm and 3-6 mm) into the subchondral bone below the osteochondral junction.
The osteoclast density was consistently highest in the subchondral cortical bone plate (0-3 mm) when compared with the deeper trabecular bone in all age groups. Furthermore, the osteoclast density was significantly higher in juvenile Thoroughbreds (foals and yearlings) within both sites in the subchondral bone when compared with adults.
The number of specimens available for study was restricted.
Osteoclasts are important in normal McIII epiphyseal and articular surface maturation and have a propensity to localise at the osteochondral junction and subchondral cortical bone plate zone in juvenile Thoroughbreds.
双膦酸盐药物针对破骨细胞介导的骨重塑，给幼年和成年赛马使用这类药物存在争议，因为人们担心这些分子会与骨矿化基质结合，可能干扰马运动员随后的骨骼生长、对运动的适应以及骨微损伤的愈合。破骨细胞参与软骨内成骨、软骨下骨重塑和骨修复。关于马破骨细胞生物学在关节表面生长和成熟中的作用存在知识空白，而这些信息对于明智使用双膦酸盐药物很重要。
测量并比较纯种马（TB）第三掌骨远端（McIII）不同部位、距关节表面不同深度以及不同年龄（0 - 84个月）的软骨下骨中的破骨细胞密度。
离体尸体研究。
收集驹、一岁马和成年马的McIII，用甲醛固定并保存在4°C。从外侧半掌骨切片，染色并对软骨退变进行评分。在免疫组织化学（组织蛋白酶K）染色切片上计数破骨细胞。比较感兴趣区域（ROI——矢状嵴、轴侧和远轴侧髁）以及软骨下骨-软骨交界处下方软骨下骨的两个深度（0 - 3毫米和3 - 6毫米）的破骨细胞密度。
与所有年龄组更深的小梁骨相比，软骨下皮质骨板（0 - 3毫米）中的破骨细胞密度始终最高。此外，与成年马相比，幼年纯种马（驹和一岁马）软骨下骨两个部位的破骨细胞密度均显著更高。
可供研究的标本数量有限。
破骨细胞在正常McIII骨骺和关节表面成熟中起重要作用，并且在幼年纯种马中倾向于定位于软骨下骨-软骨交界处和软骨下皮质骨板区域。
