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Syndecans are a family of four cell surface proteoglycans that bind to various components of the extracellular environment and can regulate many cellular behaviors including growth, adhesion, and movement. To determine whether syndecans can function during wound repair, we have examined expression of the syndecans during wound repair of adult mouse and neonatal or fetal human skin. Syndecan-1 and -4 were induced in the dermis within 12 h after incisional injury of murine or neonatal human skin. Syndecan-1 was induced primarily on endothelium, and syndecan-4 was present throughout the dermis at the site of injury. Following re-epithelialization, expression of the syndecans return to their baseline level. In marked contrast to these observations, wounded human fetal skin showed no increase in expression of syndecans. This lack of increase in the expression of syndecans by cells of the dermis correlates with prior observations that fetal skin heals without a polymorphonuclear cell infiltrate, appreciable fibrosis, or clinically apparent scar. Thus, induced expression of syndecans is not an absolute requirement for wound repair but does correlate with the occurrence of fibrosis in mature skin. These findings support the role of syndecans as regulators of cell behavior and suggest that syndecan-1 and -4 induction in the dermis may contribute to events that lead to inflammation and fibrosis.

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Cervical linear circumference (lo), extensibility and rate of creep, and the content and concentration of collagen and proteoglycans were determined on uterine cervices of rats at different reproductive stages. The inner circumference increased from 9 +/- 3 (SD) mm at the nongravid stage to a maximum of 41 +/- 5 mm at term; a significant drop to 23 +/- 2 mm occurred by 4 h postpartum with a further drop to 18 +/- 4 mm by 1 day postpartum. The extensibility and rate of creep reached their maxima 1 day before term and returned to the nongravid value by 1 day postpartum. The small (Mr = 95,000) type II dermatan sulfate proteoglycan, the major cervical proteoglycan, increased from 43 +/- 6 micrograms per cervix at the nongravid stage to 196 +/- 33 micrograms at term. The amount of this proteoglycan decreased significantly by 35% to 126 +/- 5 micrograms within 4 h postpartum and declined further to 79 +/- 16 micrograms by 1 day postpartum. The total cervical collagen content increased less than 2-fold during pregnancy, from 3.5 +/- 0.5 to 6.3 +/- 0.7 mg; a decline to 5.8 mg by 1 day postpartum was not significant. The ratio of small proteoglycan: collagen increased 2.5-fold between the nongravid state and term, then returned to the nongravid value by 1 day postpartum. Significant correlations were found between the lo and the amount of small proteoglycan per cervix (r = 0.86; n = 69) and between lo and the ratio of small proteoglycan:collagen (r = 0.83; n = 50) when data from every reproductive stage were combined. A mechanism is proposed whereby the interaction of the proteoglycan with collagen fibers might alter mechanical properties and contribute to cervical dilatation and its rapid reversal.

No abstract