A study of adriamycin‐reduced wound breaking strength in rats. An evaluation by light and electron microscopy, induction of collagen maturation, and hydroxyproline content
The cause of the reduced wound breaking strength (WBS) in adriamycin-treated animals is unknown. Differential staining of histologic sections, collagen fiber diameter measurements by electron microscopy (EM), induction of maturation, and hydroxyproline content analysis were used to examine this defect. Differential staining and formaldehyde induction of maturation revealed no differences between mature and immature collagen content in scars of adriamycin-treated and control animals. Mean collagen fiber diameters in control rats were 76 +/- 27 nm and, in adriamycin treated rats, 62 +/- 10 nm (mean +/- SD) at 21 days. There was no difference in total hydroxyproline content between ADR and C animals. However, significant differences existed between the specific activity of new or 3H-hydroxyproline (scar collagen) at 14 days (controls, 372 +/- 9 cpm; adriamycin-treated, 129 +/- 5 cpm) and at 21 days (controls, 365 +/- 11 cpm; adriamycin treated, 172 +/- 14 cpm; mean +/- SEM; P less than 0.001). It appears that the defect contributing to reduced WBS in adriamycin treated animals is not due to a collagen maturation defect but rather to a reduction in scar collagen accumulation as measured by new hydroxyproline content and reduced fiber diameter as determined by EM measurements.