Differences between serum C-reactive protein (SCRP) and synovial fluid C-reactive protein (SFCRP) concentrations in healthy animals may be influenced by the sex of the individual and associated with various factors. The objective of this study was to evaluate the disparities in SCRP and SFCRP concentrations between females and males, as well as within each sex. Sixty healthy dogs (N = 60), comprising both sexes, were enrolled in the study. Peripheral blood and knee synovial fluid samples were collected for SCRP and SFCRP analysis, respectively. Serum C-reactive protein (SCRP) and SFCRP concentrations were measured, with mean of 9.61 ± 4.96 mg/L for SCRP and 1.28 ± 3.05 mg/L for SFCRP. Notably, SFCRP concentrations were consistently lower than SCRP concentrations in both sexes. Statistically significant differences were observed between sexes for both SCRP (P = 0.021) and SFCRP (P = 0.007). Further analysis within females revealed statistically significant differences between SCRP and SFCRP concentrations (P = 0.002), whereas in males, such differences were not significant (P = 0.175). Additionally, weak correlations were found between SCRP and SFCRP concentrations for both sexes (females r = 0.07; males r = 0.29). Joint capsule thickness was assessed using ultrasonography, revealing thicker joint capsules in males. A robust positive association was noted between joint capsule thickness and the SFCRP concentration in both sexes. These findings offer valuable insights into the dynamics of CRP in the context of joint health in male and female patients, elucidating the underlying pathological mechanisms of joint disease and inflammation. Overall, this underscores the importance of considering sex-specific factors in the assessment and management of joint health, as well as in the design and interpretation of studies involving SFCRP concentrations.

健康动物血清 C 反应蛋白 (SCRP) 和滑液 C 反应蛋白 (SFCRP) 浓度之间的差异可能受到个体性别的影响，并与多种因素相关。本研究的目的是评估女性和男性之间以及不同性别之间 SCRP 和 SFCRP 浓度的差异。六十只健康的狗（N  = 60），包括性别，都参加了这项研究。收集外周血和膝关节滑液样本，分别用于 SCRP 和 SFCRP 分析。测量血清 C 反应蛋白 (SCRP) 和 SFCRP 浓度，SCRP 平均值为 9.61 ± 4.96 mg/L，SFCRP 平均值为 1.28 ± 3.05 mg/L。值得注意的是，两性的 SFCRP 浓度始终低于 SCRP 浓度。 SCRP ( P  = 0.021) 和 SFCRP ( P  = 0.007)的性别之间存在统计学显着差异。女性中的进一步分析显示 SCRP 和 SFCRP 浓度之间存在统计学显着差异（P  = 0.002），而在男性中，这种差异并不显着（P  = 0.175）。此外，两性 SCRP 和 SFCRP 浓度之间的相关性较弱（女性 r = 0.07；男性 r = 0.29）。使用超声检查评估关节囊厚度，显示男性关节囊较厚。在两性中，关节囊厚度与 SFCRP 浓度之间存在强烈的正相关关系。这些发现为了解男性和女性患者关节健康背景下 CRP 的动态提供了宝贵的见解，阐明了关节疾病和炎症的潜在病理机制。总体而言，这强调了在评估和管理关节健康以及设计和解释涉及 SFCRP 浓度的研究时考虑性别特异性因素的重要性。