Dietary glycine prevents peptidoglycan polysaccharide-induced reactive arthritis in the rat: role for glycine-gated chloride channel

Li X, Bradford BU, Wheeler MD, Stimpson SA, Pink HM, Brodie TA, Schwab JH, Thurman RG · Infection and Immunity

The best dietary-glycine joint study there is. Ankle swelling rose 2.1 mm in controls but only 1.0 mm on glycine, with attenuated inflammatory infiltration, edema and synovial hyperplasia, and TNF-alpha mRNA undetectable in glycine-fed joints. The mechanism is immunomodulation via a glycine-gated chloride channel on macrophages — blocked by strychnine — not collagen synthesis.

Population

Rats with peptidoglycan-polysaccharide-induced reactive arthritis

Intervention

Glycine-containing diet started 3 days before arthritis reactivation

Comparator

Nitrogen-balanced control diet

Limitations

Rats, and an inflammatory/reactive arthritis model rather than osteoarthritis or a cartilage-matrix endpoint. Says nothing about whether dietary glycine builds cartilage; the pathway is anti-inflammatory.