Department of Rehabilitation, Faculty of Rehabilitation, Hiroshima International University, Higashi-Hiroshima, Japan.
Connect Tissue Res. 2023 Mar;64(2):186-204. doi: 10.1080/03008207.2022.2141627. Epub 2022 Nov 5.
Osteoarthritis that develops after anterior cruciate ligament (ACL) reconstruction is a critical issue. We examined the effects of the amount of weight bearing early after ACL reconstruction on articular cartilage.
Rats were divided into groups according to the treatment received: untreated control, ACL reconstruction (ACLR), ACL reconstruction plus hindlimb unloading (ACLR + HU), and ACL reconstruction plus morphine administration (ACLR + M). ACL reconstruction was performed on the right knee throughout the groups. To assess the amount of weight bearing, one-hindlimb standing time ratio (STR; operated side/contralateral side) during treadmill locomotion was evaluated during the experimental period. At day 7 or 14 post-surgery, cartilage degeneration of the medial tibial plateau was histologically assessed.
In the ACLR group, reduction in weight bearing characterized by significantly reduced STR was observed between day 1 and 7. Reduction in weight bearing was partially attenuated by morphine administration. Compared with the control group, the ACLR group exhibited an increased Mankin score that was accompanied by increased cyclooxygenase-2 expression in the anterior region. In the ACLR + HU group, Mankin scores were significantly higher in the middle and posterior regions, and cartilage thickness in these regions was significantly thinner than those in the ACLR group. In the ACLR + M group, although chondrocyte density in the anterior region was increased, all other parameters were not significantly different from those in the ACLR group.
Our results suggest that early weight bearing after ACL reconstruction is important to reduce cartilage degeneration.
前交叉韧带（ACL）重建后发生的骨关节炎是一个关键问题。我们研究了 ACL 重建后早期负重对关节软骨的影响。
根据接受的治疗，将大鼠分为未处理对照组、ACL 重建（ACLR）组、ACL 重建加后肢去负荷（ACLR+HU）组和 ACL 重建加吗啡给药（ACLR+M）组。所有组均在右膝关节进行 ACL 重建。为了评估负重量，在实验期间通过跑步机运动评估单后肢站立时间比（STR；手术侧/对侧侧）。在手术后第 7 天或第 14 天，对内侧胫骨平台的软骨退变进行组织学评估。
在 ACLR 组中，从第 1 天到第 7 天，负重减少表现为 STR 显著降低。吗啡给药部分减轻了负重减少。与对照组相比，ACLR 组的 Mankin 评分增加，前区环氧化酶-2 表达增加。在 ACLR+HU 组中，中后部的 Mankin 评分显著升高，这些区域的软骨厚度明显比 ACLR 组薄。在 ACLR+M 组中，虽然前区的软骨细胞密度增加，但所有其他参数与 ACLR 组均无显著差异。
我们的结果表明，ACL 重建后早期负重对于减少软骨退变很重要。
