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Objective To evaluate acute intestinal injury models induced by radiation through histological analysis. Methods A total of 41 Beagle canines were randomized into control group (n=8) and 11 radiation groups (at dose of 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 30Gy, 3 each group). Animals were given single-dose from X-ray delivered at dose rates of 250cGy/min using tridimensional conformal radiotherapy (3D-CRT) on the abdomen, followed by histological analysis on the intestine. Results We successfully developed canine acute intestinal injury model using irradiation. The intestinal mucosal injury showed a dose-dependent manner. The greater radiation dose was received, the more severe pathological mucosal injury observed. For dogs that received 8Gy, their small intestine exhibited a slight grade of apoptosis and partial loss of the intestinal villi in the epithelial cells. For dogs that received moderate irradiation dose of 10-14Gy, we observed partially damaged mucosa, glandular dilatation, inflammatory infiltration, vascular congestion, and hemorrhage in their intestine tissue. For dogs that received the high dose of 16-30Gy, their intestine histologic changes included diffuse intestinal necrosis, erosions or exfoliation, as well as extensive congestion and bleeding. Conclusions A canine model of acute intestinal injury induced by irradiation in a dose-dependent manner was successfully established. This model would pave the foundation for better irradiation model development and be beneficial to develop novel and effective radioprotective agents.
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<p><b>OBJECTIVE</b>To look for the evidences of motilin receptor expression on interstitial cells of Cajal (ICC) of the rabbit.</p><p><b>METHOD</b>Smooth muscle segments with ICC were isolated from the small intestine of 10-day old rabbits. The tissue segments equilibrated in Ca(2+)-free Hanks' solution were dispersed with an enzyme solution containing collagenase type II and then Ficoll density centrifugation was used to dissociate ICC. The cells were suspended and cultured in the M199 medium. The c-kit antibody was applied to distinguish the cultured ICC. The motilin receptor was identified by immunocytochemical assay with GPR38 antibody, c-kit antibody and hoechst 33342 combined to label ICC. Cells cultured for a few days were sorted for ICC with c-kit stained green fluorescent through flow cytometry. The total RNA and proteins extracted from the sorted ICC were respectively used to verify motilin receptor on the ICC by reverse-transcriptase polymerase chain reaction (RT-PCR) and Western blotting.</p><p><b>RESULT</b>We had successfully dissociated and cultured ICC of rabbit small intestine in vitro. Fluorescent staining with c-kit antibody confirmed that the culture ICC was successful. Triple-labeled immunofluorescent staining had detected the motilin receptor on membrane of ICC. Flow cytometry analysis showed that the ratio of c-kit positive cell in the cultured cells was 64.3%. The number of sorted ICC was 6.7 × 10(5) and 5.6 × 10(6). The results of RT-PCR and Western blot confirmed that the ICC had motilin receptor expression.</p><p><b>CONCLUSION</b>Our study demonstrated presence of motilin receptor on ICC of the rabbit. The present results may suggest that ICC play an important role in gastrointestinal movement induced by motilin.</p>