Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA.
Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, 625 Harrison St, West Lafayette, IN, USA.
BMC Musculoskelet Disord. 2021 Oct 20;22(1):894. doi: 10.1186/s12891-021-04762-z.
Acrolein is a known pro-inflammatory toxic aldehyde, propagating cellular damage and tissue inflammation in humans and animal models of various diseases. Osteoarthritis (OA) has a significant inflammatory component; however, presence of acrolein in synovial fluid of joints with OA has not been previously reported. The first aim of this study was to evaluate evidence of acrolein in the synovial fluid of dogs with OA as well as in Control joints. The second aim was to determine if evidence of acrolein can be detected in synovial fluid samples that have been in a frozen state for long periods of time.
In this pilot clinical study, synovial fluid samples were prospectively collected (i.e., New samples) from a single joint of both clinically healthy (New Control, n = 5) and dogs with OA (New OA, n = 16) and frozen until the time of analysis. Additionally, frozen synovial fluid samples from a biobank (i.e., Old samples) were used to evaluate ability to detect evidence of acrolein in long-term stored samples (median of 4.89 years) in Old Control (n = 5) and Old OA (n = 5) samples. Measurements of acrolein in all synovial fluid samples was based on detection of its major protein adduct, N ε - (3-formyl-3, 4-dehydropiperidino)lysine (FDP-lysine), using the western blot method. Synovial fluid matrix metalloproteinase 2 (MMP2) was measured in all samples using the western blot method as a positive control of OA inflammation.
Acrolein-lysine adduct was detected in both Control (n = 10) and OA (n = 21) groups in both Old and New samples. Acrolein-lysine adduct and MMP2 were detectable at a lower level in the Old compared to New synovial fluid samples; however, the differences were not statistically significant (p > 0.1). The measured MMP2 levels were significantly higher in the OA compared to Control group samples (p = 0.033), but not for acrolein-lysine adduct (p = 0.30).
This study confirmed evidence of acrolein in canine synovial fluid of both OA and Control groups. Freezing of synovial fluid for up to 5 years does not appear to significantly affect the ability to detect acrolein-lysine adduct and MMP2 in these samples.
丙烯醛是一种已知的促炎毒性醛，在人类和各种疾病的动物模型中会引发细胞损伤和组织炎症。骨关节炎（OA）有明显的炎症成分；然而，以前没有报道过 OA 关节滑液中存在丙烯醛。本研究的首要目的是评估 OA 关节滑液中丙烯醛的证据，以及在对照关节中的证据。第二个目的是确定在长期冷冻的滑液样本中是否可以检测到丙烯醛的证据。
在这项初步临床研究中，前瞻性地从单个关节采集了临床健康的（新对照，n=5）和 OA 犬（新 OA，n=16）的滑液样本（即新样本），并冷冻保存直至分析。此外，还使用生物库中的冷冻滑液样本（即旧样本）来评估在长期储存样本（中位数为 4.89 年）中检测到旧对照（n=5）和旧 OA（n=5）样本中丙烯醛证据的能力。所有滑液样本中丙烯醛的测量均基于其主要蛋白质加合物 N ε -（3-甲酰基-3,4-脱水哌啶）赖氨酸（FDP-赖氨酸）的检测，使用 Western blot 方法。所有样本均使用 Western blot 法测量滑液基质金属蛋白酶 2（MMP2），作为 OA 炎症的阳性对照。
在旧和新样本中，对照（n=10）和 OA（n=21）组中均检测到丙烯醛-赖氨酸加合物。与新滑液样本相比，旧滑液样本中的丙烯醛-赖氨酸加合物和 MMP2 的检测水平较低；然而，差异无统计学意义（p>0.1）。与对照样本相比，OA 样本中的 MMP2 水平显著升高（p=0.033），但丙烯醛-赖氨酸加合物水平没有升高（p=0.30）。
本研究证实了犬 OA 和对照关节滑液中丙烯醛的证据。滑液样本冷冻保存长达 5 年似乎不会显著影响这些样本中丙烯醛-赖氨酸加合物和 MMP2 的检测能力。
