Abstract
The effect of D-glucosamine hydrochloride (GlcN) administration on cartilage metabolism in bicycle players was investigated, based on the stratified analysis utilizing biomarkers for cartilage and bone metabolism.
A randomized double-blind placebo-controlled clinical trial was conducted in 27 bicycle players. They were randomly assigned to the two groups and administrated with a placebo (n=13) or GlcN 1.5 g/day (n=14) for 3 months, and the effect of test supplements on cartilage metabolism was evaluated by analyzing a cartilage type II collagen degradation marker (CTX-II, corrected by urinary creatinine Cr) using urine samples collected before (0 month) and after the administration of test supplements (3 months).
The results indicated that CTX-II levels were not significantly different between the two groups (placebo group and GlcN 1.5 g/day group) after the administration of test supplements (P>0.2). Next, the subject (n=18) with small joint loading were evaluated based on the CTX-II level (<500 ng/mmol Cr); CTX-II levels were substantially decreased in GlcN 1.5 g/day group (n=9, P=0.05) compared with a placebo group (n=9) after the administration of test supplement. Furthermore, among these subjects, the subject (n=13) with small variation of joint loading (<20 %) were evaluated, based on the level of NTx (a bone type I collagen degradation marker); CTX-II levels were significantly decreased in GlcN 1.5 g/day group (n=7, P <0.01) compared with a placebo group (n=6) after the administration of test supplement.
These observations suggest that the daily administration of GlcN (1.5 g/day) exhibits the chondroprotective action on the subjects with small joint loading by improving cartilage metabolism via the suppression of type II collagen degradation.
