An Experimental Study Of The Effects Of Partial Cranial Cruciate Ligament Rupture On Articular Cartilage

Objective: By animal experiment to research the results of non surgery or augmentation surgery using the semitendinosus autograft to treat partial lesions of the cranial cruciate ligament (CCL) in rabbit knee, which had influenced the articular cartilage degradation of the knee joint. The purpose of this research was to provide experimental evidence on healing partial tear of anterior cruciate ligament(ACL) in clinic, in addition to reduce the osteoarthritis(OA).Methods: Thirty-six ripe New Zealand White rabbit were used in this study. Then four rabbits were selected as blank group. Others underwent partial substance resection in a middle part of CCL of both sides from the lateral, in order to create contrast self models. One knee was selected at random as experimental group to simulate ACL reconstructions using the semitendinosus tendon. The contrast group did not carry out the reconstruction surgery. Eight rabbits were enthanised separately in 4, 12, 16, 24 weeks after surgery. Through gross morphologic observation, histological section and immunity histological chemistry, observed the languishment of the cell of medial femoral condyles cartilage. Reverse transcription- polymerase chain reaction (RT-PCR) were used to detect the mRNA expression of MMP-1 in articular cartilage.Results: 1. Gross morphologic observation: cartilage degeneration in contrast group was significantly more severe than that in experimental group. Compared with blank group it was observed at week 4 and became more severe with time in both experimental group and contrast group, which had time-dependent changes. 2. Histological observation: the external situation and arrangement of cartilage of 4w, 12w, 16w, 24w in experimental group were better than contrast group. There were lots of chondrocytes which were vanished in 24w contrast group. 3. Immunity histological chemistry: there were MMP-1 masculine chondrocytes in both experimental group and contrast group. The percentage of MMP-1 masculine chondrocytes in experimental group was significantly lower than contrast group (P<0.05). 4. RT-PCR: RT-PCR showed an increase expression of mRNA of MMP-1 in cartilage in both groups with time. Compared with contrast group the mRNA expression levels of MMP-1 was significantly declined in experimental group (P<0.05).Conclusion: 1. Partial rupture of the CCL could results in time-dependent degenerative changes of the rabbit articular cartilage. 2. Partial CCL tears augmented with semitendinosus autograft could effectively reduce the development of cartilage degeneration. 3. Augmented reconstructed of the CCL with semitendinosus autograft could down-regulate the level of MMP-1 in the cartilage. This maight be one of mechanisms that operation could delay the languishment of cartilage.