Metastatic rat adenocarcinoma: histochemical evaluation of fibroblasts and extracellular matrix.

This study was based on the hypothesis that after tumour transplantation, fibroblast metabolism increases adjacent to a tumour and this increase correlates with an increase in certain components of the extracellular matrix. A serial histochemical study of the cellular metabolism and extracellular matrix in a fast-growing mammary rat carcinoma was designed. The model used was the N-nitrosomethylurea-induced adenocarcinoma. At 24, 48, 72 or 96 h after transplantation, tumours and surrounding tissues were excised and processed. Ribonucleic acid and succinate dehydrogenase stains were used to indicate cellular metabolism; the extracellular matrix was stained for collagen, elastin, acid mucopolysaccharides, mucoproteins, glycoproteins and glycolipids. The results of this histology were compared with the histology of nonneoplastic transplants. In subcutaneous tissue adjacent to neoplasia, fibroblasts were abundant and showed an increase in metabolism between 24-96 h; this was correlated with an increase in collagen. For nonneoplastic transplants, fibroblasts were present only at 96 h, and collagen increases did not occur. It is inferred from the results that the tumour transplant is responsible for the increase in fibroblast metabolism in vivo which in turn increases fibre production.