CELLULAR AND MOLECULAR BIOLOGY OF BONE AND CARTILAGE: STRUCTURE, REMODELING, PATHOLOGICAL DEGENERATION, AND REGENERATIVE THERAPEUTIC STRATEGIES

Background: Bone and cartilage are specialized connective tissues that form the structural and biomechanical foundation of the vertebrate musculoskeletal system. Despite their apparent rigidity, both tissues are metabolically dynamic, undergoing continuous remodeling throughout life. Disruption of this homeostasis underlies some of the most prevalent and disabling diseases in modern medicine, including osteoporosis—affecting over 200 million people worldwide—and osteoarthritis, estimated to affect 528 million individuals globally. Objective: To provide a comprehensive, evidence-based review of the cellular and molecular biology of bone and cartilage, encompassing their extracellular matrix composition, key cell types, signaling pathways governing remodeling and degeneration, and current regenerative and pharmacological therapeutic strategies. Methods: A systematic review of eight primary peer-reviewed sources was conducted, including original research articles, meta-analyses, and authoritative clinical practice guidelines published between 2000 and 2024.