Nucleic acid and sulphated glycosaminoglycan synthesis in the peritoneal membrane and in intra-abdominal adhesions in rat as affected by silica-induced peritonitis.

The synthesis of DNA, RNA and glycosaminoglycans was studied in the peritoneal membrane and intra-abdominal adhesions formed in rats after a single colloidal silica injection. The concentration of DNA and RNA increased from the first day of peritonitis reaching the maximum at 4--7 days in both the peritoneum and adhesions. On the other hand the synthesis of radioactive DNA and RNA from 3H-thymidine and 3H-cytidine increased during the first 12 hours and was maximal at 24 hours in the peritoneum and at 48 hours in the adhesions. Although the contents of uronic acids were maximal at 24 hours in the peritoneum and at 2--4 days in the adhesions, the maximal synthesis rate of sulphated glycosaminoglycans was observed at 5 days in the peritoneum and at 7 days in the adhesions. The difference in the uronic acid concentration and radioactivities of glycosaminoglycans was probably due to increased permeability of the peritoneal membrane and exudation. Earlier we observed that protein synthesis was maximal at 7 days and that of collagen at 3 weeks. On the basis of these and the present results it is obvious that the order of synthesis of these connective tissue components in the peritoneum after chemical peritonitis follows the pattern of tissue reaction in wound healing and in experimental subcutaneous granuloma formation. However, the activation of nucleic acid and glycosaminoglycan synthesis occurs promptly without any or with a very short lag period in the peritoneal mesenchymal tissue.