The effects of four different average molecular weights (MW) ; 0.47, 0.95, 1.52 and 2.0 × 10
6, respectively of sodium hyaluronate (HA) designated those each as HA-47, HA-95, HA-152 and SL-1010, on the neutrophil functions including chemotaxis, adhesion to the plastic plate, phagocytosis and superoxide generation, and expression of CD44 antigen were studied.
The inhibitory effect of HA on neutrophil chemotaxis was found to be dose (0.1-0.4 mg/ml) - and MW (0.47-2.0×10
6) -dependent. Neutrophils were also observed to be inhibited to adhere to a plastic plate when the cells were treated with 10 μg/ml each type of HA. However, only SL-1010 inhibited the cell adhesion at the concentration of 1 μg/ml. Phagocytosis of FITC-latex particles was also found significantly inhibited by the HA-152 and SL-1010, but not by the HA-47 and the HA-95 at the concentration of 1 mg/ml. These inhibitory effects on the chemotaxis and phagocytosis observed in the presence of HA were similarly observed when neutrophils were pretreated with and washed out SL 1010.
The generation of superoxide anions by stimulation with opsonized zymosan (OZ) was inhibited by the addition of HA, and this effect was also found to be dose- and MW-dependent.
The effect of HA on neutrophil activating antigen, CD44 was analysed after the stimulation with OZ, and the results revealed that the CD44 expression on neutrophil was down-regulated by the stimulation. The down-regulation of CD44 was inhibited by HA in a MW-dependent manner.
These results indicated that HA, especially the high MW SL-1010 might be a modulator against the activation of neutrophil to the inflammatory cascade.
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