2025 · Wang — Spontaneous Hydrogen-releasing Nanoenzyme Alleviates Osteoarthritis via Oxidative Stress Reduction and Mitochondrial Dysfunction Reversal
Super-Abstract
A newly engineered nanoenzyme that spontaneously releases hydrogen gas alleviated osteoarthritis in animal experiments by reducing oxidative stress, restoring mitochondrial function, promoting the clearance of damaged mitochondria (mitophagy), and slowing cartilage degeneration. This is a preclinical animal study; results cannot be transferred to human patients. (Journal of Nanobiotechnology, 2025.)
Commentary
Osteoarthritis (OA) is the most prevalent joint disease worldwide, driven in part by a hypoxic, ROS-rich microenvironment that impairs chondrocyte function and accelerates cartilage breakdown. Current treatments focus on symptom management rather than disease modification. Wang et al. synthesise a selenium-doped hollow mesoporous prussian blue nanoparticle coated with ammonia borane and chondroitin sulfate (Se-HMPB@AB@COS) that releases H₂ continuously at physiological conditions — no external trigger needed. The in-vivo data in OA mice show collagen II promotion, extracellular matrix protection, and reduced inflammation. The mitophagy-enhancing effect is a mechanistically interesting addition: by helping cells clear dysfunctional mitochondria, H₂ may break the ROS-inflammation feedback loop at a deeper cellular level. The study is conducted entirely in animals; the fabrication complexity and biodistribution of this nanoenzyme system require thorough pre-clinical safety assessment before any human application.
Key quotes
- „Small hydrogen molecules can readily penetrate mitochondria, specifically reducing the levels of •OH thereby protecting mitochondrial function.“ — the mechanistic basis for H₂'s mitochondria-protective role in this context
- „Hydrogen therapy can effectively enhance mitophagy and delay chondrocyte senescence.“ — a newly identified effect of H₂ in ageing joint cartilage cells
- „Se-HMPB@AB@COS encapsulated with chondroitin sulfate significantly promotes the synthesis of collagen II, inhibits the degradation of extracellular matrix, and reduces inflammatory factors.“ — the main structural and anti-inflammatory outcomes in the OA mouse model
Our assessment
This is a preclinical animal study — all results are from OA mouse models; no human data exist. The nanoenzyme platform is experimentally innovative but far from clinical translation. Osteoarthritis is a major unmet medical need, and this work contributes mechanistic insight into how H₂ could protect cartilage at the mitochondrial level. However, the fabrication complexity, biodistribution, and long-term safety of this system are entirely untested in humans. No treatment conclusions for patients can be drawn.
Study design
- Type: animal study (OA mouse model) · Model: surgically induced OA mice · H₂ delivery: spontaneous H₂ release from Se-HMPB@AB@COS nanozyme (selenium-doped hollow mesoporous Prussian blue + ammonia borane + chondroitin sulfate)
- Result: significant collagen II synthesis promotion; extracellular matrix protection; reduction of inflammatory factors; enhanced mitophagy; delayed chondrocyte senescence; mitochondrial function restoration; cartilage and mitochondrial damage reduced in vivo
Abstract
Osteoarthritis (OA), a chronic and degenerative joint disease, has become increasingly prevalent due to the aging population, posing a significant societal burden. However, despite progress, effective therapeutic options for osteoarthritis remain limited. In OA, chronic inflammation mediates a hypoxic microenvironment, leading to increased cellular energy demands. Over time, this causes mitochondrial dysfunction, favoring the accumulation of ROS, thereby perpetuating inflammation. Furthermore, reduced autophagy in aging chondrocytes hinder the clearance of damaged mitochondria, exacerbating oxidative stress. Herein, we have developed a simple and environmentally friendly strategy to fabricate hydrogen-releasing nanozymes (Se-HMPB@AB@COS) that spontaneously release hydrogen gas, effectively treating osteoarthritis through antioxidant, anti-inflammatory, and mitochondrial dysfunction reversal mechanisms. During the process of hydrogen therapy, small hydrogen molecules can readily penetrate mitochondria, specifically reducing the levels of •OH thereby protecting mitochondrial function. Our research further unveils that hydrogen therapy can effectively enhance mitophagy and delay chondrocyte senescence. In vivo, Se-HMPB@AB@COS encapsulated with chondroitin sulfate significantly promotes the synthesis of collagen II, inhibits the degradation of extracellular matrix, and reduces inflammatory factors. Overall, this study innovatively synthesized a hydrogen-releasing nanozyme, demonstrating its effectiveness in inhibiting oxidative stress, inflammation, promoting mitophagy and extracellular matrix synthesis, thereby reducing cartilage and mitochondrial damage, and delaying OA progression.
Source & links
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