EXPRESSION OF TYPE-I AND TYPE-IV COLLAGEN MESSENGER-RNAS IN HEALING GASTRIC-ULCERS - A COMPARATIVE-ANALYSIS USING ISOTOPIC AND NONRADIOACTIVE IN-SITU HYBRIDIZATION

The sensitivity and practicability of in situ hybridization methods ut ilizing isotopic or non-radioactive labeling were compared. The aim of this study was to determine whether digoxigenin-labeled riboprobes ar e as sensitive as S-35-labeled probes to detect changes in type I and IV procollagen expression in an animal model of rat gastric ulcer. Bot h labeling and detection methods yielded similar results, with a super imposable signal distribution in the specimens, High levels of procoll agen type I and IV transcripts were observed in spindle-shaped cells, presumably fibroblasts or myofibroblasts, localized in the ulcer base and rim. The increased expression of these collagen types suggests a r emarkable upregulation of collagen expression during the healing of ga stric ulcers. Liver tissue adhering to perforated ulcers displayed sig nals related to non-parenchymal cells, with hepatocytes demonstrating no detectable transcripts of type I or IV collagen genes. Due to the i dentical pattern of signal distribution by both hybridization techniqu es it is concluded that non-radioactive in situ hybridization is of va lue in monitoring highly expressed genes and yields results similar to those achieved with radioactive probes. In these cases, non-radioacti ve techniques are preferable because they are performed more rapidly a nd do not require handling of isotopes.