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Characterization of macrophages elicited by intraperitoneal injection of hyaluronate
Abstract:
Hyaluronate of 120,000 molecular weight has been injected in the peritoneal cavity of mice to study its effect on migration of inflammatory cells in vivo. After one day a dose-dependent granulocyte migration is observed. Three days later the number of granulocytes is greatly reduced and macrophages form about half of the total cell population. Hyaluronate-elicited macrophages show a decreased 5'-nucleotidase and an increased acid phosphatase activity as compared to resident macrophages. The production of superoxide anion in response to the phorbol ester tetradecanoyl-phorbolacetate, and the phagocytic activity are also enhanced. Macrophages elicited by hyaluronate secrete growth factor(s) for non-lymphoid mesenchymal cells. It is concluded that hyaluronate in vivo stimulates the migration of inflammatory cells, thus causing the recruitment of a population of stimulating macrophages. These effects may explain previous reports on the acceleration of wound healing by hyaluronate.
Insights
Hyaluronate injection in mice stimulates inflammatory cell migration, recruiting macrophages with enhanced functions. These findings suggest hyaluronate accelerates wound healing by modulating immune responses.
Area of Science:
- Immunology
- Biochemistry
- Cell Biology
Background:
- Hyaluronate (HA) is a glycosaminoglycan with known biological roles.
- Its effects on inflammatory cell migration in vivo require further elucidation.
Purpose of the Study:
- To investigate the in vivo effects of 120,000 molecular weight hyaluronate on inflammatory cell migration.
- To characterize the functional properties of hyaluronate-elicited macrophages.
Main Methods:
- Intraperitoneal injection of hyaluronate into mice.
- Analysis of peritoneal lavage fluid cell populations and differential counts.
- Assay of macrophage enzyme activities (5'-nucleotidase, acid phosphatase).
- Measurement of superoxide anion production and phagocytic activity.
- Assessment of growth factor secretion by elicited macrophages.
Main Results:
- Dose-dependent granulocyte migration observed within 24 hours post-injection.
- Macrophages constituted approximately 50% of the cell population by day three.
- Hyaluronate-elicited macrophages exhibited decreased 5'-nucleotidase and increased acid phosphatase activity.
- Enhanced superoxide anion production and phagocytic activity in elicited macrophages.
- Secretion of growth factors for non-lymphoid mesenchymal cells by elicited macrophages.
Conclusions:
- In vivo hyaluronate administration stimulates inflammatory cell migration.
- Recruitment of a distinct macrophage population with enhanced functional capabilities.
- These immunomodulatory effects of hyaluronate may contribute to accelerated wound healing.