Differential expression of related molecules after acute injury of rabbits’ anterior cruciate ligament and medial collateral ligament

Abstract Objective: This study aimed to assay expression of the mRNA and proteins for injuring- and angiogenesis-associated molecules at 3 days, 1week, 2weeks, 4weeks and 6 weeks after anterior cruciate ligament or medial collateral ligament injury in male New Zealand White rabbits. Methods: Models similar to those of clinical patients were used to establish acute partial injuries of the anterior cruciate ligament and medial collateral ligament at 3 days, 1 week, 2 weeks, 4 weeks and 6 weeks and normal control groups. Molecular biological changes in male rabbits were detected at different time points after anterior cruciate ligament and medial collateral ligament injury by H&E staining, reverse transcriptase chain reaction and westren blotting. Results: Marked differences were found in the postinjury changes in gene levels and proteins in the anterior cruciate ligament compared to the medial collateral ligament. There was no increase in mRNA expression of TIMP3, TGF-βand PRG4 in the injured anterior cruciate ligament at any time point. However, the levels of these genes tended to increase in the injured medial collateral ligament. In contrast, MMP-13 mRNA levels were significantly increased in the injured anterior cruciate ligament, but not in the medial collateral ligament. Furthermore, vascular endothelial growth factor decreased following injury to both the anterior cruciate ligament and medial collateral ligament, with the difference being a slight decrease in the medial collateral ligament and a significant decrease in the anterior cruciate ligament. Similarly, protein blots showed higher protein expression of type I and type III collagen in the injured medial collateral ligament than in the anterior cruciate ligament. Conclusion: The results show that there were drastic differences in angiogenesis, collagen and Matrix metalloproteinases after anterior cruciate ligament and medial collateral ligament injury. It can be found that the repair ability of the anterior cruciate ligament and medial collateral ligament after injury may be related to the differences in molecular expression.