The underlying mechanism of partial anterior cruciate ligament injuries to the meniscus of knee joint in rabbit models

Abstract

Background The diagnosis, treatment and efficacy evaluation of anterior cruciate ligament (ACL) remains controversial. This research aims to investigate the underlying mechanism of partial ACL injuries to the meniscus degeneration in rabbit knee. Methods Sixty New Zealand, white rabbits were randomly divided into three groups: the anteromedial bundle (AMB) splitting, the posterolateral bundle (PLB) splitting and a control group. Finally, eight rabbits were sampled randomly on the second, fourth and eighth weeks respectively. We observed the typical form of the meniscus through HE staining. Expressions of inflammatory factors including interleukin-1β (IL-1β) and IL-17 in the knee joint fluid were determined by means of an ELISA. Analysis of the mRNA expressions of MMP-13 was performed to evaluate the inflammatory mediators in the pathogenesis of the meniscus. Results HE staining results showed that the surface was rough and the tissues were loose displaying collagen fibers of varying thickness. Both IL-1β and IL-17 in the synovial fluid, and the positive rate of MMP-13 in addition to MMP-13 mRNA showed a demonstrable increase treads from the 2nd to the 8th week. The significant difference was found ( P <0.05) compared to the control group. Conclusion Our findings illustrated that the elevated levels of IL-1β and IL-17, along with increased MMP13 expression, resulting in meniscus degradation in the rabbit knee joint model with partial ACL injury. When the partial ACL injury on the different bundles occurred, the reconstruction of the reserved AMB or PLB must be operated on time due to uncertainty of conservative treatment.