High Prevalence of Caecal Dysplasia in Wistar/Furth Substrain Rats
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Spontaneous colon tumor
Offspring of spontaneous colon tumor prone rats (WF/O) bred in our laboratory developed tumors in a very low incidence (less than 0.2 %), but about half of these rats had dysplastic epithelium with frequent erosion in the caecum. In nine animals (4.4%) submucosal glands of the caecum were observed. These dysplasia accompanied inflammatory cell reactions and regional lymph nodes were enlarged and packed with many plasma cells. Hybrid of WF/O rats and other inbred Long-Evans strain (LE) rats, having no dysplastic lesion of the caecum, had caecal dysplasia in a low incidence (10%). These data suggest that genetic factor(s) play an important role in the occurrence of caecal dysplasia in WF/O rats. These changes may be a precondition to the spontaneous occurrence of tumors in the proximal portion of the ascending colon with the aid of promoting factor(s).
Hiroshima Journal of Medical Sciences
Hiroshima University School of Medicine