Substantive molecular and histological changes within the meniscus with tears

Area of Science:

• Orthopedics and Sports Medicine
• Molecular Biology
• Biochemistry

Background:

• The knee meniscus is crucial for joint biomechanics but poorly understood at the molecular level.
• Meniscal tears, with or without anterior cruciate ligament (ACL) tears, are common knee injuries.
• Understanding molecular changes in meniscal tissue is vital for diagnosing and treating knee injuries.

Purpose of the Study:

• To investigate molecular and pathological differences in meniscal tissue based on injury type.
• To compare menisci with simple tears versus those with combined meniscal and ACL tears.
• To explore the role of specific genes and microRNAs (miRNAs) in meniscal degeneration.

Main Methods:

• Collected meniscal tissue from three groups: normal (A), simple tear (B), and tear with ACL tear (C).
• Analyzed pathological changes and quantified gene expression (ACAN, ADAMTS5, COL10A1, CEBPβ, MMP13) and miRNA levels (miR-381-3p, miR-455-3p, miR-193b-3p, miR-92a-3p) using molecular techniques.
• Assessed patient knee function pre- and post-operatively using Lysholm and IKDC scores.

Main Results:

• Injured menisci (B and C) showed increased expression of ADAMTS5, COL10A1, CEBPβ, MMP13, and miRNAs, with decreased ACAN compared to normal (A).
• Group C (meniscus + ACL tear) exhibited higher gene and miRNA expression and lower ACAN than Group B (simple tear).
• Fibrochondrocytes in injured menisci showed high expression of specific genes and miRNAs; Group B patients had better post-operative scores than Group C.

Conclusions:

• Meniscal injury promotes degeneration, particularly when combined with an ACL tear.
• Investigated miRNAs may play a role in the degenerative process of meniscal tissue.
• Combined meniscal and ACL injuries are associated with poorer patient joint function outcomes.