Octaarginine

Collagen-induced arthritis (CIA) is an autoimmune murine model of rheumatoid arthritis in which immunization with type II collagen (CII) emulsified in an adjuvant induces a T cell- and autoantibody-driven inflammatory arthritis characterized by synovial hyperplasia, immune cell infiltration, and joint destruction. The model typically relies on genetically susceptible mouse strains (e. g. , DBA/1) and reproduces key features of human rheumatoid arthritis, including anti-collagen immune responses and progressive joint inflammation. Disease onset generally occurs within ~3-4 weeks after immunization, depending on antigen/adjuvant combinations and protocol variation. The immunopathology is driven by adaptive immune activation against CII, leading to systemic and local joint inflammation mediated by pro-inflammatory cytokines and effector immune cells, making CIA a standard preclinical platform for evaluating immunomodulatory and anti-arthritic interventions.

Apoptosis is a regulated, generally non-lytic cell-death pathway that removes unwanted, damaged, infected, or abnormal cells through coordinated morphological changes, caspase activation, DNA fragmentation, and membrane remodeling. The intrinsic apoptosis pathway is controlled mainly by mitochondrial outer membrane permeabilization, BCL-2 family proteins, cytochrome c release, apoptosome formation, caspase-9 activation, and downstream executioner caspase-3/7 activation. The extrinsic apoptosis pathway is initiated by death receptors such as Fas, TNFR, and TRAIL receptors, which recruit adaptor proteins and activate caspase-8 before engaging executioner caspases or mitochondrial amplification through BID cleavage. Apoptosis is linked to many phenotypes, including cancer cell killing, tissue homeostasis, immune regulation, neurodegeneration, infection response, and treatment-induced cytotoxicity; unresolved questions include how apoptosis interacts with necroptosis, pyroptosis, ferroptos