Musculoskeletal System

Rheumatoid Arthritis (RA) Model

• Collagen-Induced Arthritis (CIA): The gold-standard model, induced by immunization with bovine type II collagen and Freund's adjuvant.
• Collagen Antibody-Induced Arthritis (CAIA): Utilizes injection of anti-type II collagen antibodies for a rapid, synchronized onset of disease, bypassing the immune sensitization phase.

Acute Gouty Arthritis Model

Induced by intra-articular injection of monosodium urate (MSU) crystals into a joint (e.g., rodent ankle) to simulate acute crystal-induced inflammation and pain.

Knee Osteoarthritis (KOA) Model

• Surgical: Destabilization of the medial meniscus (DMM) or anterior cruciate ligament transection (ACLT).
• Chemical: Intra-articular injection of mono-iodoacetate (MIA) to induce chondrocyte death and rapid joint degeneration.

Frozen Shoulder Model

Typically induced by immobilization of the rodent shoulder joint or by surgical injury/injection of TGF-β to model adhesive capsulitis and fibrosis.

Critical-Sized Bone Defect Models

• Femoral Drill Hole Bone Defect: A standardized drill hole in the femoral condyle or diaphysis.
• Femoral Condyle Defect Model: A created defect in the weight-bearing condyle.
• Cranial Defect Model: A critical-sized defect in the calvaria (skull) for evaluating ectopic bone formation.
• Radial/Tibial Defect Model: Large Segmental Radius/Tibial Defect, created by surgically removing a segment of bone, which will not heal without intervention.

Mandibular & Alveolar Bone Defect

• Mandibular Defect Model: A defect created in the jawbone, relevant for dental and craniofacial research.
• Alveolar Bone Defect Model: A defect in the bone surrounding the teeth, used to study periodontitis and bone loss.

Joint & Soft Tissue Injury Models

• Knee Joint Cartilage Injury Model: Created by chondral or osteochondral defect to model cartilage repair.
• Meniscal Injury Model: Involves injury or resection of the knee meniscus.
• Rotator Cuff Injury Model: Involves transection of the supraspinatus tendon in the shoulder.
• Bone-Tendon Injury Model: Focuses on the healing at the interface, such as the patellar tendon insertion.

Spinal Injury Model

• Atlantoaxial Injury Model: Involves injury or instability at the C1-C2 junction of the spine.

Closed Fracture Model

Typically induced by a controlled, closed three-point bending technique using a specialized apparatus, often in the tibia or femur, to create a standardized fracture without open surgery.

Open Osteotomy Model

Involves surgical creation of a fracture (osteotomy), which can be stabilized with internal or external fixation (e.g., plates, pins) for more controlled healing studies.

Radius Fracture Model

A specific model focusing on fracture healing in the forearm bone, often stabilized with internal fixation.

Complete Spinal Cord Transection Model

Involves complete surgical transection of the spinal cord at a specific level (e.g., thoracic) to study severe spinal cord injury and axonal regeneration.

Lumbar Intervertebral Disc Degeneration Model

Induced by puncture of the intervertebral disc with a needle or by mechanical overload to simulate disc degeneration and low back pain.

Spine Fusion Model

Involves surgical decortication of vertebrae and implantation of graft material (autograft/allograft/bone substitutes) to model spinal fusion surgery.

Post-Laminectomy Anti-Adhesion Model

Evaluates strategies to prevent fibrotic tissue adhesion following a laminectomy (removal of the lamina) procedure.

Muscle Injury & Disease

• Acute Skeletal Muscle Contusion Model: Induced by a controlled impact to a muscle (e.g., tibialis anterior) to model crush injury.
• Achilles Tendon Rupture Model: Involves surgical transection or tenotomy of the Achilles tendon.
• Sarcopenia Model: Achieved through natural aging in rodents or by denervation.
• Muscular Dystrophy Model: Utilizes genetically modified mice (e.g., mdx mice for Duchenne muscular dystrophy).

Metabolic Bone Disease

• Osteoporosis Model: Induced by ovariectomy (OVX) in females to model postmenopausal osteoporosis, or by glucocorticoid administration.
• Femoral Head Necrosis Model: Induced by steroid injection, surgical dislocation, or ligation of blood vessels to disrupt blood supply.

Surgical Intervention Models

• Anterior Cruciate Ligament Reconstruction Model: A complex surgery in small or large animals to model the clinical ACL reconstruction procedure and graft healing.
• Hip Replacement Model: Involves surgical implantation of a prosthetic joint in large animals to study implant osseointegration and wear.

Infection & Inflammatory Models

• Osteomyelitis Model: Induced by direct bone inoculation with bacteria (e.g., Staphylococcus aureus) to model bone infection.
• Periodontitis Model: Induced by ligature placement around the molar tooth combined with bacterial inoculation to model inflammatory gum disease and bone loss.