Collagen synthesis in rat skin and ileum fibroblasts is affected differently by diabetes-related factors

Untreated diabetes reduces wound strength: a concomitant reduction in collagen deposition has been found in cutaneous wounds but not in intestinal anastomoses. This raises the question if collagen synthesis in fibroblasts from skin and intestine reacts differently to the diabetic state. Fibroblast lines were established from healthy rat skin and ileum. Diabetic rat serum was collected from hyperglycaemic rats 3 days after intravenous injection of streptozotocin (200 mg/kg). Fibroblast cultures were grown to confluency in foetal calf serum and maintained in various concentrations of glucose, insulin, normal or diabetic rat serum. Collagen synthesis was measured by incorporation of [³H]-proline into Collagenase-Digestible-Protein. Collagen synthesis in fibroblasts from both skin and ileum was not affected by increasing glucose concentrations. Insulin strongly and specifically stimulated collagen synthesis in skin fibroblasts whereas in ileum fibroblasts only a nonspecific increase of total protein synthesis was observed. In skin fibroblasts, diabetic rat serum stimulated collagen synthesis to a significantly lesser extent than normal rat serum, whereas in ileum fibroblasts stimulation by serum was far less explicit and no difference was observed between normal and diabetic serum. The fact that ileum fibroblasts respond less strongly to culture in diabetic serum than skin fibroblasts may explain our prior finding that wound collagen accumulation in intestinal anastomoses is virtually unaffected during diabetes and supports the existence of tissue-specific healing responses.