Assessment of apoptosis, MMP-1, MMP-3, TIMP-2 expression and mechanical and biochemical properties of fresh rabbit's medial meniscus stored two weeks under tissue culture conditions

INTRODUCTION: The purpose of this study was to assess apoptosis, the expression of MMP-1, MMP-3 and TIMP-2, as well as the mechanical and biochemical properties of fresh rabbit medial meniscus after 2 weeks stored under tissue culture conditions. MATERIAL AND METHODS: The study material included 26 rabbit's medial menisci. Fourteen menisci were stored for 2 weeks under tissue culture conditions. Thirteen menisci were subjected to immunohistochemistry tests. Apoptosis (TUNEL method) and the expression of MMP-1 (collagenase-1), MMP-3 (stromelysin-2) and TIMP-2 (tissue inhibitor of metalloproteinases-2) were estimated semiquantitatively. The remaining menisci were tested mechanically and biochemically. The mechanical properties were assessed by the degree of elasticity. Biochemical composition was based on the content analysis of water, total collagen and glycosaminoglycans. RESULTS: As in the control group, the conducted study did not reveal any apoptosis in the stored menisci. The study group showed a slight expression of MMP-1 (0.27 ±0.19), MMP-3 (0.30 ±0.20) and TIMP-2 (0.33 ±0.20) – no statistically significant difference from controls. The degree of elasticity was 28.51 ±1.53 in the study group, and this did not statistically differ from the control group. No significant biochemical differences were identified in any other monitored parameter. CONCLUSIONS: The conducted in vitro study did not show any negative influence of a 2-week storage period under tissue culture conditions on the apoptosis and expression of MMP-1, MMP-3 and TIMP-2 in rabbit fresh menisci, nor any impact on their mechanical and biochemical properties.