1. Volume 9, Issue 4, Pages 215-220 (September 2003)
Reactive oxygen species depolymerize hyaluronan: involvement of the hydroxyl radical 
Kenji Yamazaki, Kanji Fukuda, Masataka Matsukawa, Fumihiko Hara, Koji Yoshida, Masao Akagi, Hiroshi Munakata, Chiaki Hamanishi 
Pathophysiology 
Volume 9, Issue 4, Pages (September 2003)
DOI: /S (03)

2. Fig. 1
Kinetics of the generation of hydroxyl radical. Hydroxyl radicals were generated by the reaction of 45 μM H2O2 and 5 μM FeSO4. Using L-012 (5 μg/ml), the photointensity of the chemiluminescence from the reaction mixture was measured. ○, H2O2; ●, H2O2+Fe2+; ▴, H2O2+Fe2++catalase (100 μM). One representative experiment of three is shown.
Pathophysiology 2003 9, DOI: ( /S (03) )

3. Fig. 2
The effect of citrulline on the generation of hydroxyl radicals. Hydroxyl radicals were generated via the reaction between H2O2 and Fe2+ in the absence or presence of different concentrations of citrulline. Using L-012, the photointensity of the chemiluminescence at 45 s after the addition of FeCl2 was measured. Data are expressed as the mean±S.D. for four samples. Representative results of two different experiments are shown. *, P<0.05; **, P<0.01 vs. control (none).
Pathophysiology 2003 9, DOI: ( /S (03) )

4. Fig. 3
Depolymerization of HA. HA was incubated with H2O2 in the absence (□) or presence of the Fe2+ ion to generate the hydroxyl radical for 5 min (●) and for 60 min (○). Alteration of molecular weight was determined using gel chromatography. The concentrations of HA in the fractions were determined by an ELISA. Representative results of two different experiments are shown.
Pathophysiology 2003 9, DOI: ( /S (03) )

5. Fig. 4
Effect of catalase on hydroxyl radical-induced depolymerization. HA was incubated in the absence (A) or presence (B) of the Fe2+ ion and H2O2 to generate the hydroxyl radical. In addition, DMSO (10 mM, C) and citrulline (100 μM, D) were added with the Fe2+ ion and H2O2 to determine if it had an inhibitory effect on the hydroxyl radical-induced depolymerization of HA.
Pathophysiology 2003 9, DOI: ( /S (03) )

6. Fig. 5
Effect of H2O2 on HA, in vitro. Chondrocytes embedded in alginate beads were cultured in the absence (H2O2 alone) (●) or presence (H2O2+Fe2+) (○) of the hydroxyl radical. The alteration of molecular weight was determined using gel chromatography. The concentrations of HA in the fractions were determined by an ELISA. Representative results of two different experiments are shown.
Pathophysiology 2003 9, DOI: ( /S (03) )