Porcine anterior cruciate ligament fibroblasts are similar to cells derived from the ligamentum teres, another non-healing intra-articular ligament

Porcine ligament fibroblasts were cultured from the anterior cruciate (ACL), medial collateral (MCL), and ligamentum teres (LT). There were no apparent differences in confluent cellular morphology among the ligament cell types as evaluated by phase contrast microscopy. The proliferation rate of MCL cells from 24-120 h was significantly higher (p < 0.05) than that of cells from either the LT or the ACL. MCL cells produced more collagen and less non-collagenous protein than the LT and ACL as determined by [3H]proline incorporation. This resulted in MCL cells producing a higher percentage (37%, p < 0.05) of collagen relative to total protein than either the ACL (28%) or the LT (32%). The MCL cells produced a significantly higher percentage (34.7%, p < 0.05) of type-III collagen relative to total type-I and III collagen than either the ACL (29.2%) or the LT (29.5%). The LT and MCL cells had similar and significantly greater coverage of in vitro wounds than the ACL. This study provides the first in vitro study of the LT and demonstrates that fibroblasts from the LT and ACL, two ligaments that heal poorly, have similar in vitro characteristics, with the exception of wound healing.