Fine Structural Changes in the Ileum of Mice Fed on δ-Endotoxin-Treated Potatoes and Transgenic Potatoes

Abstract

The present work has been designed to study the effect of feeding on transgenic potatoes, which carry the CryI gene of Bacillus thuringiensis var. kurstaki strain HD1, on the light and electron microscopic structure of the mice ileum, in comparison with feeding on potatoes treated with the ‘δ‐endotoxin’ isolated from the same bacterial strain. The microscopic architecture of the enterocytes of the ileum of both groups of mice revealed certain common features such as the appearance of mitochondria with signs of degeneration and disrupted short microvilli at the luminal surface. However, in the group of mice fed on the ‘δ‐endotoxin’, several villi appeared with an abnormally large number of enterocytes (151.8 in control group versus 197 and 155.8 in endotoxin and transgenic‐treated groups, respectively). Fifty percent of these cells were hypertrophied and multinucleated. The mean area of enterocyte was significantly increased (105.3 µm2 in control group versus 165.4 µm2 and 116.5 µm2 in endotoxin and transgenic‐treated groups, respectively). Several forms of secondary lysosomes or auotophagic vacuoles were recognized in these cells. These changes were confirmed with the scanning electron microscope which revealed a remarkable increase in the topographic contour of enterocytes (23 µm in control group versus 44 µm and 28 µm in endotoxin and transgenic‐treated groups, respectively) at the divulged surface of the villi. The basal lamina along the base of the enterocytes was damaged at several foci. Several disrupted microvilli appeared in association with variable‐shaped cytoplasmic fragments. Some of these fragments contained endoplasmic reticulum, as well as ring‐shaped annulate lamellae. In addition, the Paneth cells were highly activated and contained a large number of secretory granules. These changes may suggest that δ‐endotoxin‐treated potatoes resulted in the development of hyperplastic cells in the mice ileum. Although mild changes are reported in the structural configuration of the ileum of mice fed on transgenic potatoes, nevertheless, thorough tests of these new types of genetically engineered crops must be made to avoid the risks before marketing. Copyright © 1998 John Wiley & Sons, Ltd.

Effects of genetically modified T2A-1 rice on faecal microflora of rats during 90 day supplementation

“…However, it was reported that Cry1Ac could not only bind to the intestinal surfaces of Balb/c mice but could also influence some epithelial cell functions 32. In another study, hyperplastic cells and no apparent tissue damage were observed in the ileum of mice fed with Bt protein 33…”

Evaluation of stress‐ and immune‐response biomarkers in Atlantic salmon, Salmo salar L., fed different levels of genetically modified maize (Bt maize), compared with its near‐isogenic parental line and a commercial suprex maize

“…The level of δ ‐endotoxin was not measured in the feed or any organs in the present study. However, feeding rats with potatoes treated with isolated ‘ δ ‐endotoxin’ from a Bt strain carrying the Cry1 gene, resulted in structural changes, such as hypertrophied and multinucleated enterocytes and development of hyperplastic cells in mice ileum (Fares & El‐Sayed 1999). Proliferation of gastrointestinal mucosa of rat intestine is reported after feeding rats with GM potatoes expressing the Galanthus nivalis lectin (Ewen & Pusztai 1999).…”

Risk assessment of genetically modified crops for nutrition and health

“…Over time, studies assessing the risk of GM foods have improved, and publications have begun including sensible and specific indicators about the safety of GM food consumption in accordance with changes in the guidelines. In publications reviewed by Pryme and Lembcke, 42 as well as in those mentioned in this review, the conclusions have varied from no alteration of the nutritional value of the GM food tested, 11,45,51,61,65,67,71,80 to minimal detrimental effects on the nutritional value, 81 to in vivo submicroscopic effects in different animal species 23,54,55,57,82 …”