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دراسات عن سمية وسرطنة الأفلاتوكسين فى حيوانات التجــــارب
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Abstract: The present work studied the effect of aflatoxin on toxicity and carcinogenicity on laboratory animals by the following experiments:
1) Studies on toxicity of aflatoxin on laboratory animals.
2) Studies on carcinogenicity of aflatoxin on laboratory animals. In the first experiment, 88 weaned rats of both sexes weight
from (80-100) gm have been divided into two groups.
The first group of 44 rats were divided into 22 rats male and 22 rats female, both sexes did not receive aflatoxin and used as control. The 2nd group of 44 rats were divided into 22 rats male and 22 rats female both sexes received 0.02 ppm aflatoxin Bl/rat dailyfor 15 weeks in drinking water
All rats were subjected to clinical symptoms observation. Three rats from each of the first and second group of males and females were sacrificed at 5, 10 and 15 weeks respectively of the experiment. All sacrificed rats were subjected to post mortem, weight of vital organ and histopathological examination.
Rats of second group which received 0.02 ppm aflatoxin Bl/rat daily for 15 week showed nervous manifestation, erected hair and marked decrease in body weight in both males and females. Means of liver, spleen and kidney in gm/l00 gm body weight increased in both males and females at 5, 10 and 15 weeks respectively than control group.
The post-mortem lesions in second group which received 0.02 ppm aflatoxin Bl/rat daily for 15 weeks were observed. Livers in both males and females were congested enlarged and blood oozed from their cut surface. Kidney in both males and females were pale in colour and slightly enlarged. Petechial haemorrhages were observed on surfae of the lungs.
The percentage of mortality in the first group (control) were 0.0% in both males and females. While in 2nd group which received 0.02 ppm aflatoxin Bl/rat daily for 15 weeks, the percentage of mortality reached 9.09% in both males and females.
Histopathological changes in the second group which received 0.02 ppm aflatoxin Bl/rat daily for 15 weeks at 5, 10 and 15 weeks respectively revealed hepatotoxicity as determined by centrilobular hepatocytes varied from being degenerated to necrotic. A mild proliferation of bile ducts from portal tracts to sinusoides in the form of oval cell with pale basophilic cytoplasm was observed.
In the second experiment, 94 weaned rats of both sexes weight from (80-100) gm have been divided into 3 groups. The first group of 36 rats divided into 18 rats male and 18 rats female, both sexes did not receive aflatoxin and used as control. The second group of 22 rats were divided into 11 rats male and 11 rats female, those rats were the rest of rats from toxicity experiment both sexes received 002 ppm aflatoxin B1/rat daily for 15 weeks in drinking water. The 3rd group of 36 rats were divided into 18 rats male and 18 rats female. Both sexes received 0.01 ppm aflatoxin Bl/rat 3 day/weekly for 30 weeks in drinking water.
All rats were subjected to clinical symptom observation, 3 rats from the first group, second group and third group both males and females were sacrificed at 30 weeks and 45 weeks from begening of experiment.
All sacrificed rats were subjected to post mortem, weight of vital organs, determination of aflatoxin BI and its metabolites in liver tissue, histopathological examination, immunohistochemistry examination (lectin binding) and nucleic acid DNA (feulgon reaction).
Rats of second and third group both males and females showed sharp decrease in body weight, rough and erected hair, loss of appetite and sedation espeasily at late stage of experiment. Means of liver and
kidney weight in gm/l00 gm body weight in both males and females in 2nd group and 3rd group at 30 weeks and 45 weeks were increased than control. While mean of spleen weight were slightly decreased than control.
The post mortem lesions on second and third groups at 30 weeks and 45 weeks in both males and females. Liver showed severe congestion, enlargement, stricke of heamorrhage on surface of liver and necrotic foci. In addition heamoragic ascites were observed in abdomanal cavity. kidney were pale in colour and enlarged. Intestine was congested and filled with gas.
It was found that total aflatoxin Bl and its metabolites in second group in males were 33 45 ng/gm liver and 3150 ng/gm liver after 30 weeks and 45 weeks respectively. While in females the amount of aflatoxin detected were 4060 ng/gm liver and 3305 ng/gm liver after 30 and 45 weeks respectively. The total of aflatoxin Bl and its meabolites in 3rd group in males were 3400 ng/gm liver and 3695 ng/gm liver after 30 weeks and 45 weeks respectively. While in females the amount of aflatoxin detected were 3240 ng/gm liver and 3145 ng/gm liver after 30 weeks and 45 weeks respectively.
The percentage of mortality in the first group (control) were 0.0% in both males and females. While the percentage ofmortality in 2nd group in males were 45.45% and in females were 36.36% . The percentage of mortality in second group in males were 66.66% and in females were 50.0%.
Histological changes observed in second group after 30 weeks till 60 weeks demonstrated enlarged hepatocytes with enlarged nuclei contained more than one eosinophilic nucleoli and this was associated with mutlifocal areas of clear cells, binucleated hepatocytes and hyperplastic nodules. While the hepatic changes after 60 weeks post treatment until the end of experiment were similar in males and females. The incidence of hepatic changes increased at this period in addition to cholangioma which characterized by proliferative growth of the bile duct epithelium which form acini or papillary structure along the cyst wall. The histological findings in the third group at 30 weeks post tratment were mild degenerative and necrotizing changes particularly in periportal hepatocytes. In addition to multifoci of coagulative necrosis, oval cells hyperplasia, kupffer cell activation and in addition mononuclear cells were seen in some portal areas. The findings at 45 weeks were foci of vacuolated hepatocyts with central nuclei and this vacuolation was a result of an accumulation of glycogen.
Furthermore, these changes from 45 weeks till the end of experiment were more or less similar to the second group. The results recorded 4 types of foci, eosinophilic, basophilic, clear cell and even- tually hyperplastic. Some of these foci could be considered as preneoplastic.
Immunohistochemistry (lectin binding), lectins were used as histochemical markers to compare the expression of membrane glycoproteins in hepatocellular carcinoma and hepatic nodules. It indicated that there was a total' loss of reduction in lectin staining without clustering in eosinophilic foci only while other foci did not reveal any reduction or clustering of lectin staining. The result was confirmed by staining nucleic acid DNA (feulgon reaction). Hyperplastic hepatocytes were demonstrated with feulgon reaction.
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| Publication year |
1996
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| Availability location |
7 شارع نادى الصيد - الدقى - الجيزة(المعمل المركزى لتحليل متبقيات المبيدات والعناصر الثقيلة فى الأغذية)
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| Availability number |
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| Organization Name |
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| Country |
Egypt
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| Department |
Microbiology Analysis
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| Author(s) from ARC |
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| Agris Categories |
Animal diseases
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| Proposed Agrovoc |
Laboratory animals Experiments;Rats-- Diseases;Aflatoxins-- Toxicology;
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| Publication Type |
PhD Thesis
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