Active form of lipoic acid protected cartilage cell glutathione and slowed damage in mice
This 2026 study in mouse cartilage cells and mice found that dihydrolipoic acid (DHLA), the active form of lipoic acid, reduced the loss of glutathione and the glutathione enzyme GPX4 when cells were exposed to an inflammatory signal. It suppressed ferroptosis, an iron-dependent form of cell death, and slowed cartilage damage in mice with osteoarthritis.
What they did
The researchers exposed cartilage cells from mice to IL-1 beta, an inflammatory signal, to trigger ferroptosis, and treated them with DHLA. They measured markers of ferroptosis and of cartilage building and breakdown, and used computer analysis and drugs that block two proteins, FOXO1 and TXNIP, to work out how DHLA acted.
They then induced osteoarthritis in mice by surgery to the knee's meniscus, treated them with DHLA, and examined the joints with micro-CT scanning and under the microscope.
What they found
In cells, DHLA reduced the rise in reactive oxygen species, ferrous iron, lipid peroxidation and malondialdehyde caused by IL-1 beta, and reduced the loss of glutathione, GPX4 and SLC7A11, proteins the study tracked as part of the ferroptosis defence. It also reduced the loss of proteoglycans, collagen II, aggrecan and SOX9, and held back the rise in the cartilage-cutting enzymes MMP13, MMP3 and ADAMTS5.
DHLA reversed IL-1 beta's effects on FOXO1 and TXNIP. Blocking FOXO1 abolished DHLA's protection, and blocking TXNIP restored it. In mice, DHLA reduced bony spurs and cartilage damage, lowered MMP13 and TXNIP, and preserved collagen II, GPX4 and FOXO1 in the cartilage.
What it can't tell us
This was done in mouse cells and mice, not people. The osteoarthritis was caused by surgery, which is different from age-related joint wear. The abstract does not give the DHLA dose, how it was given, how long treatment lasted or how many animals were used. DHLA is the reduced form of lipoic acid; the study does not test lipoic acid taken by mouth.
Why it matters
This study links lipoic acid's active form directly to cartilage glutathione and to GPX4, the glutathione enzyme that protects against ferroptosis. It also shows DHLA holding back MMP13 under inflammatory stress. It extends Han 1997, which showed how lipoic acid helps cells make glutathione, into cartilage cells and a mouse model of osteoarthritis.
The paper
- Chen Y, Fang J, Zhou Z et al. Dihydrolipoic acid suppresses ferroptosis in chondrocytes to ameliorate the progression of osteoarthritis by modulating the FOXO1/TXNIP signaling pathway. Free Radic Biol Med 2026.
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