White Jamie L, Salinas Evelia Y, Link Jarrett M, Hu Jerry C, Athanasiou Kyriacos A
Integrative Pathobiology Graduate Group, University of California, Davis, Davis, CA.
Henry Samueli School of Engineering, Department of Biomedical Engineering, University of California, Irvine, Irvine, CA.
J Equine Vet Sci. 2021 Jan;96:103294. doi: 10.1016/j.jevs.2020.103294. Epub 2020 Oct 15.
A significant portion of equine lameness is localized to the stifle joint. Effective cartilage repair strategies are largely lacking, however, recent advances in surgical techniques, biomaterials, and cellular therapeutics have broadened the clinical strategies of cartilage repair. To date, no studies have been performed directly comparing neonatal and adult articular cartilage from the stifle across multiple sites. An understanding of the differences in properties between the therapeutic target cartilage (i.e., adult cartilage) as well as potential donor cartilage (i.e., neonatal cartilage) could aid in selection of optimal harvest sites within a donor joint as well as evaluation of the success of the grafted cells or tissues within the host. Given the dearth of characterization studies of the equine stifle joint, and in particular neonatal stifle cartilage, the goal of this study was to measure properties of both potential source tissue and host tissue. Articular cartilage of the distal femur and patella (P) was assessed in regards to two specific factors, age of the animal and specific site within the joint. Two age groups were considered: neonatal (<1 week) and adult (4-14 years). Cartilage samples were harvested from 17 sites across the distal femur and patella. It was hypothesized that properties would vary significantly between neonatal and adult horses as well as within age groups on a site-by-site basis. Adult thickness varied by site. With the exception of water content, there were no significant biochemical differences among sites within regions of the distal femur (condyles and trochlea) and the patella in either the adult or neonate. Neonatal cartilage had a significantly higher water content than adult. Surprisingly, biochemical measurements of cellularity did not differ significantly between neonatal and adult, however, adult cartilage had greater variance in cellularity than neonatal. Overall, there were no significant differences between neonatal and adult glycosaminoglycan content. Collagen per wet weight was found to be significantly higher in adult cartilage than neonatal when averaged across all levels. In terms of biomechanical properties, aggregate modulus varied significantly across the condyles of adult cartilage but not the neonate. Neonatal cartilage was significantly less permeable, and the Young's modulus of neonatal cartilage was significantly higher than the adult. The tensile strength did not vary in a statistically significant manner between age groups. An understanding of morphological, histological, biochemical, and biomechanical properties enhances the understanding of cartilage tissue physiology and structure-function relationships. This study revealed important differences in biomechanical and biochemical properties among the 17 sites and among the six joint regions, as well as age-related differences between neonatal and adult cartilage. These location and age-related variations are informative toward determining the donor tissue harvest site.
马的跛行有很大一部分局限于膝关节。然而，目前有效的软骨修复策略仍很匮乏，不过，外科技术、生物材料和细胞治疗学的最新进展拓宽了软骨修复的临床策略。迄今为止，尚未有直接比较来自膝关节多个部位的新生马和成年马关节软骨的研究。了解治疗目标软骨（即成年软骨）以及潜在供体软骨（即新生软骨）之间的特性差异，有助于选择供体关节内的最佳取材部位，以及评估移植细胞或组织在宿主体内的成功情况。鉴于对马膝关节，尤其是新生马膝关节软骨的特性研究匮乏，本研究的目的是测量潜在来源组织和宿主组织的特性。对股骨远端和髌骨的关节软骨，就动物年龄和关节内特定部位这两个特定因素进行了评估。考虑了两个年龄组：新生马（<1周）和成年马（4 - 14岁）。从股骨远端和髌骨的17个部位采集软骨样本。假设新生马和成年马之间以及各年龄组内不同部位的特性会有显著差异。成年软骨厚度因部位而异。除了含水量外，在股骨远端（髁和滑车）区域以及髌骨内，成年马和新生马各部位之间在生化方面没有显著差异。新生软骨的含水量显著高于成年软骨。令人惊讶的是，新生马和成年马在细胞数量的生化测量上没有显著差异，然而，成年软骨在细胞数量上的差异比新生软骨更大。总体而言，新生马和成年马的糖胺聚糖含量没有显著差异。在所有水平上平均计算时，发现成年软骨每湿重的胶原蛋白含量显著高于新生软骨。就生物力学特性而言，成年软骨髁间的聚集模量有显著差异，而新生软骨则没有。新生软骨的渗透性显著更低，新生软骨的杨氏模量显著高于成年软骨。年龄组之间的拉伸强度没有统计学上的显著差异。对形态学、组织学、生化和生物力学特性的了解有助于增进对软骨组织生理学以及结构 - 功能关系的理解。本研究揭示了17个部位以及六个关节区域之间在生物力学和生化特性方面的重要差异，以及新生马和成年马软骨之间与年龄相关的差异。这些位置和年龄相关的变化对于确定供体组织取材部位具有指导意义。
