Expression of SPARC (secreted protein, acidic and rich in cysteine) in healing intestinal anastomoses and short bowel syndrome in rats

Due to the proposed functions in soft tissue repair, we evaluated the spati al and temporal distribution of SPARC, a counteradhesive, matricellular gly coprotein in healing intestinal anastomoses and short bowel syndrome (SBS) in rats. Intestinal anastomoses were performed in the jejunum of male Wista r rats. SBS was induced by resecting 70% of the small bowel. In situ hybrid ization was performed to localize SPARC mRNA and immunohistochemical studie s for locating the SPARC protein. The granulation tissue in the anastomotic area exhibited immunoreactivity for SPARC at all time points. The level of expression was maximal at seven to nine days. Endothelial cells of capilla ries, smooth muscle cells, fibroblastic cells, and macrophages, as well as mesothelial cells on the serosal surface, were stained. The immunoreactivit y was mostly intracellular. SPARC mRNA transcripts were localized to the ed ges of the anastomotic area at days 1 and 4 and on the newly formed granula tion tissue later. The expression of SPARC mRNA was maximal at seven days a nd decreased thereafter. Both in normal controls and in SBS, SPARC was expr essed in endothelial cells of submucosal capillaries and in smooth muscle c ells but not in epithelium. Based on the restricted temporal and spatial di stribution during the healing of intestinal anastomoses and in SBS we propo se that SPARC plays a significant role in intestinal repair and adaptation.