Early changes in lapine menisci during osteoarthritis development: Part II: molecular alterations

Area of Science:

• Biochemistry
• Molecular Biology
• Orthopedics

Background:

• Osteoarthritis (OA) is a prevalent degenerative joint disease.
• Meniscal and ligament injuries significantly increase the risk of developing knee OA.
• Early molecular and cellular changes in menisci following injury are critical for understanding OA pathogenesis.

Purpose of the Study:

• To investigate molecular and cellular alterations in medial and lateral menisci after anterior cruciate ligament (ACL) transection in rabbits.
• To characterize the early stages of OA development in meniscal tissues at 3 and 8 weeks post-surgery.

Main Methods:

• Rabbit meniscal tissues were analyzed for DNA and RNA concentrations.
• Semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) was used to assess mRNA levels of key molecules.
• In situ DNA fragmentation was evaluated using the TUNEL assay to detect apoptosis.

Main Results:

• Medial meniscus showed elevated RNA yields and increased apoptosis (TUNEL assay) at 3 and 8 weeks post-ACL transection.
• DNA concentrations decreased in the medial meniscus by 8 weeks.
• RT-PCR revealed significant changes in mRNA levels for collagens, proteoglycans, and inflammatory markers in both menisci, with distinct patterns in the medial versus lateral meniscus.

Conclusions:

• ACL transection induces early and complex molecular alterations and apoptosis, predominantly in the medial meniscus.
• These findings highlight the medial meniscus's vulnerability in the early stages of OA following ACL injury.
• The study provides insights into the molecular mechanisms underlying post-traumatic OA initiation.