Effects of diffused soluble steroid on capsules around experimental breast prostheses in rats

Saline-filled miniprostheses were implanted beneath the dorsal panniculus carnosus of rats. The control prostheses contained only saline, while the experimental prostheses contained soluble methylprednisolone sodium succinate. At 10-day intervals the in situ compressibility of the tissue mound around the implants was measured mechanically. At 60 and 120 days, the control mounds were harder than those around the steroid prostheses, and the control prostheses were surrounded by a thicker capsular membrane. The control capsules contained more non-collagenous protein than the steroid modified capsules. We suggest that this non-collagenous protein may be related to the proteopolysaccharide cement which binds the fibers of immature scar together--and that the effect of our steroid treatment was to reduce this proteopolysaccharide component of the capsule membrane and thereby cause its dissolution.