Fwd: Fine Structural Changes in the Ileum of Mice Fed on -Endotoxin-Treated Potatoes

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" Fine Structural Changes in the Ileum of Mice Fed on Endotoxin-

Treated Potatoes and Transgenic Potatoes "

Abstract

 

Nagui H. Fares*

Adel K. El-Sayed**

Natural Toxins

Volume 6, Issue 6, 1998

Pages: 219-233

 

Published Online: 29 Jun 1999

 

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 -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 -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 -

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. 1998 John Wiley & Sons, Ltd. Ileum

final and longest segment of the small intestine. It is specifically

responsible for the absorption of vitamin B12 and the reabsorption of

conjugated bile salts . The ileum is about 4 m (13 feet) in length

and extends from the jejunum (the middle section of the small

intestine) to the ileocecal valve, which empties into the colon

(large intestine). The ileum is suspended from the abdominal wall by

the mesentery. The smooth muscle of the ileum's walls is thinner than

the walls of other parts of the intestines, and its peristaltic

contractions are slower. The ileum's lining is also less permeable

than that of the upper small intestine. Small collections of

lymphatic tissue (Peyer's patches) are embedded in the ileal wall,

and specific receptors for bile salts and vitamin B12 are contained

exclusively in its lining; about 90 percent of the conjugated bile

salts in the intestinal contents is absorbed by the ileum.

 

*Department of Zoology, Faculty of Science, Ain Shams

University, Cairo, Egypt

**Department of Entomology, Faculty of Science, Ain Shams

University, Cairo, Egypt

 

** NOTICE: In accordance with Title 17 U.S.C. Section 107, this

material is distributed for research and educational purposes only.

**

 

 

 

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