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Biomomentum多軸機械測試儀Mach-1應用：使用壓痕法繪制正常和骨關節炎小鼠的關節軟骨生物力學特性

 

Mapping Articular Cartilage Biomechanical Properties of Normal and Osteoarthritic Mice Using Indentation (OARSI Poster)

Osteoarthritis Research Society International (OARSI), 2015 April 30, Seattle, WA, United States

Purpose: Due to their size (~1mm), mouse models pose significant challenges to map biomechanical properties over their articular surfaces. The purpose of this study was to determine if an automated indentation technique could be used to map the biomechanical properties of the articular surfaces in murine knees and to identify early alterations of the articular cartilage of a mouse strain (STR/ort) that spontaneously develops osteoarthritis (OA) on the medial side of their knees.

Materials and Methods: The biomechanical measurements were performed ex vivo, on the left femoral condyles and tibial plateaus of five healthy Balb/c males (age of 12-15 weeks) and five age- and sex-matched STR/ort mice, using a 3-axis mechanical tester (Mach-1 v500css, Biomomentum, Laval) equipped with a multiple-axis load cell. Indentation measurements (30-42/surfaces) were performed using a 0.35 mm diameter spherical indenter (30 m indentation in 1 second with 20 seconds relaxation). Following biomechanical testing, the articular surfaces were fixed in 4% paraformaldehyde for histological assessment. Data reported is the structural stiffness at an indentation depth of 10m. To compare the structural stiffness between healthy and OA-developing animals each articular surface were divided into 4 regions, exterior medial (I), inner medial (II), inner lateral (III) and exterior lateral (IV). Data is reported as the mean ± SE (n= 5) for each of these regions. Statistical analysis was performed by ANOVA.

Results: In healthy animals, mapping of the structural stiffness at an indentation depth of 10 ?m showed a spatial distribution similar to that of larger animals (Figure 1 & 2, insert). The structural stiffness of the lateral and inner half of the medial condyles (Figure 1) was similar in OA and healthy mice. The stiffness of the exterior lateral plateau was also not significantly different OA and healthy mice. In contrast, the stiffness of the exterior half of the medial condyle in OA mice (5.9±0.7 N/mm) was significantly lower than that of the healthy mice (10.2±1.1 N/mm, ANOVA, p<0.05). The structural stiffness of the exterior medial condyle and the inner half of the lateral plateaus in OA mice was inferior to that of healthy mice (ANOVA, p<0.05).

Conclusions: This study shows that this automated indentation technique can map the biomechanical properties of murine knee joints. The mapping of mechanical properties shows similar distribution patterns to those previously observed for larger species (human, sheep and rat). The identification of cartilage regions with lower structural stiffness, at sites known to develop OA in the STR/ort strain, suggests this method can be used to identify and characterize OA affected articular surfaces. Studies are ongoing to validate, by histology, the cartilage quality of the affected areas. These results show that indentation mapping could be used in mouse models to test the efficacy of drugs aiming to inhibit cartilage degradation or improving its healing in OA or following a joint injury.

使用壓痕法繪制正常和骨關節炎小鼠的關節軟骨生物力學特性（OARSI海報）

骨關節炎研究學會（OARSI）

目的：由于其尺寸（?1mm），小鼠模型對在其關節表面上繪制生物力學特性提出了巨大的挑戰。這項研究的目的是確定是否可以使用自動壓痕技術來繪制鼠膝關節表面的生物力學特性，并確定自發發展成骨關節炎的小鼠品系（STR / ort）的關節軟骨的早期改變（OA）位于膝蓋內側。

材料和方法： 使用三軸機械裝置，對五名健康的Balb / c雄性（12-15周齡）和五只年齡和性別相匹配的STR / ort小鼠的左股骨dy和脛骨平臺進行離體生物力學測量。測試儀（Mach-1 v500css，Biomomentum，Laval）配備了多軸稱重傳感器。使用直徑為0.35 mm的球形壓頭（1秒內壓入30 m，松弛20秒）進行壓痕測量（30-42 /表面）。經過生物力學測試，將關節表面固定在4％多聚甲醛中以進行組織學評估。報告的數據是壓痕深度為10m時的結構剛度。為了比較健康動物和OA發育動物的結構剛度，將每個關節表面分為4個區域，外部內側（I），內部內側（II），內側（III）和外側（IV）。數據報告為這些區域中每個區域的平均值±SE（n = 5）。通過ANOVA進行統計分析。

結果：在健康的動物中，壓痕深度為10 µm時的結構剛度圖顯示出與較大動物相似的空間分布（圖1和2，插圖）。在OA和健康小鼠中，內側les外側和內側一半的結構剛度（圖1）相似。外側高原的剛度也與OA小鼠和健康小鼠沒有顯著差異。相反，OA小鼠內側con外側一半的剛度（5.9±0.7 N / mm）顯著低于健康小鼠（10.2±1.1 N / mm，ANOVA，p <0.05）。OA小鼠外media內側和外側平臺內側的結構剛度低于健康小鼠（ANOVA，p <0.05）。結論：這項研究表明，這種自動壓痕技術可以繪制出鼠膝關節的生物力學特性圖。力學性能的映射顯示出與以前針對較大物種（人類，綿羊和大鼠）觀察到的分布模式相似的分布模式。在已知在STR / ort應變中發展為OA的部位鑒定出具有較低結構剛度的軟骨區域，表明該方法可用于鑒定和表征OA影響的關節表面。正在進行研究以通過組織學驗證受影響區域的軟骨質量。這些結果表明，壓痕圖譜可用于小鼠模型，以測試旨在抑制軟骨降解或改善OA或關節損傷后軟骨愈合的藥物的功效。