A comparison of in vitro and in vivo gastric mucosal cell kinetics.

In order to determine whether organ culture of gastric mucosa preserves in vivo kinetic alterations, a comparison of in vivo and in vitro measurements of cell proliferation was made on antral mucosa from rats treated with the carcinogen methyl-nitro-nitrosoguanidine, administered orally for up to 30 weeks. Morphologic, morphometric and cell kinetic features in gastric mucosa were observed in vivo in treated and control rats. Similar in vitro measurements were made on mucosa from treated and control rats after a further 24-hour organ culture. All carcinogen-treated stomachs showed erosions, with widespread areas of glandular architectural irregularity which were more widespread after 30 weeks carcinogen treatment. Organ cultures showed good preservation of these morphologic features. In areas of architecturally normal mucosa, the carcinogen caused an increase in antral pit vertical column counts. This alteration was preserved after organ culture of carcinogen-treated mucosa. Cell birth rates and [3H]thymidine flash labeling indices were raised in architecturally normal mucosa from carcinogen-treated animals. These kinetic indices continued to be elevated after organ culture, though the in vitro values were lower than in vivo. Cell birth rates in architecturally abnormal mucosa from carcinogen-treated animals did not differ significantly from adjacent morphologically normal mucosa. Despite evidence of epithelial cell loss with depression of kinetic activity on organ culture compared with in vivo results, organ culture gives consistent results which reflect methyl-nitroso-nitrosoguanidine-induced changes and is of value for further in vitro investigations.