Healing of incisional wounds in stomach and duodenum. Collagen distribution and relation to mechanical strength.

The present study was performed to determine the changes in and distribution of collagen concentration around a healing incision in rat stomach and duodenum. These concentrations were related to the mechanical properties presented previously. Wounds were made in the nonglandular (rumen) and the glandular oxyntic parts (corpus) of the stomach and in duodenum. Specimens were cut parallel to the incision line and hydroxyproline contents and dry defatted weight were measured. Wounds were investigated 50 to 40 days after operation. Of the intact tissues the nonglandular part of the stomach had twice the collagen concentration of the glandular oxyntic part and duodenum, which did not differ from each other. The healing wounds in the glandular oxyntic part of the stomach and duodenum showed the most rapid increase in collagen concentration in the incision line and 40 days postoperatively both had collagen concentrations significantly greater than those of intact tissues. Wounds in the nonglandular part of the stomach only reached the level of intact tissue after 40 days. The dimensions of the biochemically active zones around incisions in stomach and duodenum remain essentially unchanged for 40 days after operation. A relation between the development of collagen concentration and mechanical strength was shown. These findings indicate that would healing in stomach and duodenum is rapid, that collagen is the primary factor in the mechanical properties and that the highest activity is limited to a zone close to the incision line. The width of the biochemical zone remains constant.