Histomorphological analysis of the effects of chitosan hydrogel enriched with bioactive compounds extracted from the marine sponge Dysidea robusta in an osteoarthritis model.

• Grant number: 25/03656-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2025
• End date: August 31, 2026
• Field of knowledge: Health Sciences - Physiotherapy and Occupational Therapy
• Principal Investigator: Ana Claudia Muniz Renno
• Grantee: Anna Luiza Matavelli
• Host Institution: Instituto de Saúde e Sociedade (ISS). Universidade Federal de São Paulo (UNIFESP). Campus Baixada Santista. Santos , SP, Brazil

Abstract

Osteoarthritis (OA) is a chronic degenerative joint disease, characterized by the continuous deterioration of cartilage, associated with damage to underlying tissues, such as the formation of osteophytes. The symptoms caused by the disease may lead to the individual's withdrawal from their occupations and a reduction in social participation. Therefore, the development of innovative and effective therapeutic interventions for the treatment of this condition is of great importance. Intra-articular viscosupplementation appears promising, and chitosan (QT) polysaccharides emerge as excellent candidates for an injectable hydrogel in viscosupplementation. Furthermore, the compositional diversity of marine sponges makes them a valuable source for obtaining bioactive compounds, highlighting their essential role in pharmaceutical and biotechnological applications.Given this, the aim of this proposal is to evaluate the effects of QT hydrogel enriched with bioactive compounds extracted from the marine sponge Dysidea robusta on morphology and the promotion of joint regeneration in an experimental OA model. For this purpose, OA will be induced by collagenase in the knee of Wistar rats. Subsequently, intra-articular injections of QT hydrogel enriched with bioactive compounds from Dysidea robusta will be administered.After the experimental periods, histological analysis will be performed on sagittal sections of dissected knees stained with Hematoxylin-Eosin and Safranin-O fast green. Qualitative assessment will include the analysis of cellularity and proteoglycan content, following established histological grading systems. Morphometric analysis will be conducted using image analysis, measuring cartilage thickness and counting chondrocytes. Immunohistochemistry will investigate the presence of TNF-¿, using specific antibodies and DAB staining. The results will be analyzed using light microscopy. (AU)