الفهرس 
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Abstract
Gluten is a protein compound found in some grains such as wheat, barley and oats. It is also available in some cosmetics, such as: lip balm, some nutritional supplements, medicines and it is also used in making some foods, such as: pastries and pasta, as it gives them cohesion and elasticity.
Eating foods that contain gluten in some people causes celiac disease (CD), which is a chronic disease that results from the reaction of the body’s immune system to gluten protein. This is accompanied by damage to the lining of the small intestine and thus its flattening, which makes it difficult for the intestine to absorb elements and reduce nutritional value of food.
The present investigation deals with the genotoxic and cytotoxic effects of gluten on bone marrow chromosomes, DNA content and histological structure of liver of male albino mice (Mus musculus). Forty CD-1 male albino mice (16-17 weeks old and 25-30 g) were used. They were divided into four groups and each group contained 10 mice as follows:
group (1): This group (10 mice) was kept without treatment and served as control.
group (2): This group (10 mice) was orally fed non-consecutive three times a week with glacial acetic acid (0.02M) for four weeks as a negative control group.
group (3): This group (10 mice) was orally fed non-consecutive three times a week with gluten (1.5 g/kg b.wt.) dissolved in glacial acetic acid (0.02M) for four weeks.
group (4): This group (10 mice) was orally fed non-consecutive three times a week with gluten (3g/kg b.wt.) dissolved in glacial acetic acid (0.02M) for four weeks.
Treating mice with gluten (1.5g /kg b.wt) induced structural and numerical chromosomal aberrations on bone marrow cells. The structural aberrations included centromeric attenuation, deletion, fragment, centric fusion, end to end associations, ring chromosome, beaded chromosome, chromatid and chromosome gaps while the numerical aberrations were polyploidy. Treatment with gluten (3 g/kg b.wt) also induced sticky chromosomes.
Statistical analysis showed that chromosomal aberrations were significantly increased (p < 0.05) by dose. In the 4th groups (mice treated with 3 g/kg b.wt of gluten) after four weeks of treatment 3 non-consecutive days weekly the centromeric attenuation, deletion, fragment and centric fusion showed highly statistical mean (80 ±2.45, 76.6 ±7.3, 76.8 ±7.29 and 72.2 ±4.02 respectively) compared to control and negative control groups. Statistical mean was (76.8 ±11.07, 65.6 ±8.5, 65.6 ±8.5 and 56.8 ±7.12) respectively for the same structural aberrations as for the 3rd group which received oral dose 1.5 g /kg b.wt of gluten compared to control and negative control groups.
A decrease in the mitotic index was also observed in the bone marrow cells of male albino mice groups that were treated with gluten at doses of (1.5 g/kg b.wt) and (3 g/kg b.wt) three non-consecutive days weekly for four weeks. In groups 3 and 4, the percentage of mitotic index (66.6 ±2.04) and (54 ±5.94) was significant (p < 0.001) decreased less than that of the control group (91.8±7.15) and negative control group (74.6 ±5.33).The results showed that this decrease was highly statistically significant (p < 0.05) in the mitotic index in bone marrow treated cells compared to the control and negative control groups.
Current study of bone marrow chromosomal C-banding and G-banding analysis showed that all bone marrow chromosomes of the control male albino mice were found to have C-bands at or close to their centromeric regions except the Y chromosome which appeared without C-bands. Additionally, they showed that all bone marrow chromosomes of the control, male albino mice were clearly observed with G-band patterns of different thickness, degree of staining and number of G-bands.
Also, results of C-banding and G-banding analysis confirmed the genotoxicity and cytotoxicity of gluten on bone marrow cells of male albino mice by showing the frequency of structural and numerical chromosomal aberrations resulted from gluten administration. at the level of chromosomal bands, using the C-banding technique, that all chromosomes are telocentric.
C-bands were clearly observed in the centromere region, which represents areas of heterochromatin or non-homologous chromatin, in all pairs of homologous chromosomes, except for the Y sex chromosome. It contains no bands in the centromeric region. C-bands have been used to study structural and numerical chromosomal abnormalities.
BY using the G-banding technique, this study showed the clear presence of G-bands in all pairs of chromosomes, but these bands differ in thickness and staining degree, as well as the number of bands in each chromosome. The study showed that all autosomal and sex chromosomes contain G-bands. The G-banding technique was used to study the chromosomal structure and distinguish between pairs of chromosomes within groups that are difficult to distinguish between in the normal chromosomal structure, in addition to studying the types of structural and numerical chromosomal abnormalities that appeared as a result of treatment with gluten.
Micronucleus assay results indicated that gluten induced genotoxicity in bone marrow cells and the number of micronucleated polychromatic erythrocytes (MNPCEs) was gradually increased significantly (p < 0.05) by the increase of dose in treated groups with gluten when compared to the control and negative control groups.
The current results of comet assay indicated that treatment with gluten significantly (p < 0.05) increased DNA damage in the liver cells by the increase of dose in treated groups with gluten when compared to the to control and negative control groups.
Results of quantitative real time reverse transcriptase polymerase chain reaction (qRT-PCR) analysis showed the treatment with gluten significantly (p < 0.05) increased DNA damage in the liver cells by the increase of dose in treated groups with gluten when compared to the to control and negative control groups.
Histological examination of the liver also revealed histopathological changes. The severity of these lesions has been observed to be dose dependent. The main histopathological features induced in the liver cells of group (3) of mice that treated with gluten (1.5g/Kg b.wt) were sever vacuolar degeneration in hepatocytes , some nuclei of hepatocytes showing pyknosis and karyolysis with activation of van Küpffer cells. The severity of these changes was in group (4) treated with 3 g/kg b.wt. of gluten for 4 weeks 3 non-consecutive days weekly of treatment.
Also liver of mice treated with gluten (3g/Kg b.wt) showed a focal area of mononuclear inflammatory cells between hepatocytes and presence of area of poorly differentiated hepatocellular carcinoma. That demonstrates the pathogenesis of liver damage in CD with clarity.
In conclusion, results of the present study indicated that gluten (1.5 g/ kg b.wt) and (3g/kg b.wt ) was highly clastogenic and cytotoxic as it induced very harmful genetic damage on bone marrow chromosomes and DNA content of male albino mice even after a low dose (1.5g/Kg b.wt) of gluten treatment, also histopathological structure of liver of male albino mice.
Currently, a gluten-free diet is the only effective way to deal with celiac disease. That refers to the restriction of gluten-containing foods in the diet of people with gluten sensitivity. Beneficial effect of the gluten-free diet on the risk of carcinogenesis also has been proven in several modern studies. Patients with celiac disease can only be treated by avoiding gluten-containing foods for the rest of their lives. The products that are currently on the market as gluten-free are a lifeline.
Thus, the study recommends that avoid using packaged foods, baked and fast foods that contain large quantities of gluten and be replaced by gluten-free diets, fruits and vegetables especially for people with celiac disease (CD). We hope that gluten free diets (GFD) be more available in markets and more awareness campaigns will be conducted for their beneficial sides.