TY - JOUR AU - Flores-Sáenz,M. AU - Chico,B. AU - García Alonso,M.C. AU - Clemente de Arriba,C. AU - Aguado-Henche,S. KW - histology KW - intra-articular rats KW - nanostructures KW - orthopedic procedures KW - particle injections KW - reproducibility of results KW - Wistar T1 - Intra-Articular Injection in Wistar Rats: Standardization and Experimental Validation of a Precise Protocol for Nanomaterial Administration LA - eng PY - 2026/01/01/ T2 - Nanomaterials SN - 2079-4991 VL - 16 IS - 1 PB - Multidisciplinary Digital Publishing Institute (MDPI) AB - (1) Background: Intra-articular injection is a fundamental technique in preclinical research for evaluating therapeutics and inducing joint disease models in rodents. However, the absence of standardized and validated protocols compromises reproducibility and translational validity. (2) Methods: This study establishes and experimentally validates a refined protocol for precise intra-articular injection in the knee of adult male Wistar rats. The comprehensive procedure specifies anatomical landmarks (medial border of the patellar tendon), instrumentation (27 G needle, 100 µL Hamilton syringe), a maximum volume of 35 µL, and operative verification criteria based on tactile feedback. Experimental validation was performed by administering a suspension of wear particles (2.35 mg/mL) generated from tribocorrosion tests of CoCr surfaces biofunctionalized with graphene oxide-hyaluronic acid (GO-HA) into the left knee of five rats. (3) Results: Histological analysis using the cutting–grinding technique and Toluidine Blue staining confirmed the exclusive intra-articular localization of particles in all injected animals (5/5 success rate). Qualitative assessment revealed abundant particulate distribution within the synovial space, with numerous individual particles and multiple aggregates observed per high-power field, without evidence of extravasation in any case. (4) Conclusions: The protocol demonstrated high intra-operator repeatability and provides a reliable, ethically refined tool for precise intra-articular administration of nanomaterials and for generating robust joint disease models, thereby enhancing reproducibility and animal welfare in preclinical research. DO - 10.3390/NANO16010009 UR - https://portalcientifico.uah.es/documentos/697e9dfc4f95b66d0e7b42d0 DP - Dialnet - Portal de la Investigación ER -