Collagen of the dystrophic hamster diaphragm.

The collagen content of the diaphragm was measured in normal and dystrophic hamsters aged 130 and 270 days. The diaphragm collagen content was greater in dystrophic hamsters than in control hamsters of the same age. The effect was greater in the older hamsters whether the collagen content was expressed in terms of the percentage of dry weight, in relation to surface area, or as total collagen. This increase was apparently at the expense of muscle tissue and may be a major factor contributing to respiratory muscle weakness as dystrophy advances.