Betulinic Acid Attenuates Osteoarthritis via Limiting NLRP3 Inflammasome Activation to Decrease Interleukin-1β...

Area of Science:

• Biochemistry
• Immunology
• Pharmacology

Background:

• Osteoarthritis (OA) is a prevalent degenerative joint disease.
• NLRP3 inflammasome activation and subsequent interleukin-1β (IL-1β) secretion are implicated in OA progression.
• The protective effects and mechanisms of betulinic acid (BA), a birch extract, against OA remain largely unexplored.

Purpose of the Study:

• To investigate the potential of betulinic acid (BA) in preventing osteoarthritis (OA).
• To elucidate the underlying mechanisms by which BA may exert protective effects against OA, focusing on the NLRP3 inflammasome pathway.

Main Methods:

• In vivo studies utilized an OA mouse model with gait analysis, ELISA, micro-CT, SEM, histological, IHC, IF staining, and AFM.
• In vitro studies assessed caspase-1, IL-1β, and GSDMD-NT levels in bone marrow-derived macrophages (BMDMs) using ELISA, western blot, and immunofluorescence.
• Mice received intraperitoneal injections of 5 and 15 mg/kg BA.

Main Results:

• Betulinic acid (BA) administration (5 and 15 mg/kg) postponed OA progression in a mouse model.
• BA treatment alleviated DMM-induced cartilage deterioration, subchondral bone sclerosis, and synovial inflammation.
• In vitro, BA inhibited NLRP3 inflammasome activation in BMDMs, reducing IL-1β maturation and secretion.

Conclusions:

• Betulinic acid (BA) demonstrates a protective effect against osteoarthritis (OA).
• BA attenuates OA by inhibiting NLRP3 inflammasome activation, thereby decreasing IL-1β maturation and secretion.
• These findings suggest BA as a potential therapeutic agent for OA management.