Shalom Sylvester, Andugala (2009) Role of Aspirin and its additive effect along with Vitamin C on the development of Gastric Tumours induced by carcinogen (Nitrosopiperidine) in Rats. Masters thesis, Christian Medical College, Vellore.
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Abstract
INTRODUCTION: Gastric cancer is one of the leading causes of death amongst cancer patients. It is surpassed only by lung cancer as the most common of the malignancies. Delay in the diagnosis of gastric cancer is one the main causes for its lethal nature. The pathogenesis of gastric cancer is a complex process involving different stages of development in malignancy ranging from chronic active gastritis to dysplasia and metaplasia and eventually, malignancy. A number of causative factors have been implicated in the transformation of normal gastric mucosa into malignant cells. Environmental factors include infection by H. pylori, presence of nitrites in the food which act as carcinogens (nitrosamines) and lack of fresh fruit and vegetables. Host factors include chronic gastritis and partial gastrectomy status which favors reflux of bile and alkaline intestinal secretions. Patients with blood group A have been found to be more susceptible to gastric cancer. A positive family history, hereditary non-polyposis colon cancer syndrome and familial gastric carcinoma syndrome (E-cadherin mutation) suggest that genetic factors seem to have a role in the predisposition to gastric cancer. Among the environmental factors, an important one seems to be exposure to carcinogen, perhaps in the diet. There is a world wide geographic distribution of gastric cancer with higher incidence in countries like Japan and some parts of South America and lower incidences in Western Europe and United States. Studies done on migrant population, those who have moved in to areas of low incidence from areas of high incidence, have shown that environmental, genetic and cultural factors seem to influence predisposition to gastric cancer. This study aims at producing a gastric cancer model in rats using a carcinogen to induce malignancy. As carcinogens, mainly nitrosamines, in the diet have been implicated in causing gastric cancer; this study aims at using a carcinogen, a nitrosamine, to induce gastric cancer in rats. With such a model in mind, the study also aims to look at the influence of Aspirin and Vitamin C in modifying the progression of gastric cancer induced by the carcinogen. The results of this study, if found to be significant, could be used for further study in a human model. As gastric cancer propagates through various stages of development, could Aspirin be used to alter the progression of disease if picked up early by gastroscopy is the question under study. The implications of this study being that if a patient has been diagnosed to have any early features of malignancy which may include chronic atrophic gastritis or dysplasia , does long term intake of aspirin prevent progression of disease? This study aims to determine if this would be possible on an animal model. AIMS AND OBJECTIVES: 1. To create an animal model for carcinogen induced gastric cancer in rats. 2. To Study the effect of aspirin and vitamin C in modifying the progression of gastric cancer induced by carcinogen in the animal model. MATERIALS AND METHODS: This experiment was conducted on the Wistar breed of rats. The animals were obtained from the National Centre for Biological Sciences, Bangalore. Total number of rats required to conduct this experiment was 60. This sample size was obtained using the data from the study conducted by P.J. Hu et al on rats where gastric cancer was induced using a carcinogen. Approval of the college research board and the animal ethics committee was obtained before the commencement of the study. The rats were divided in to 3 groups, each group having 20 rats. The rats were caged together in fours. The experiment was conducted in the Animal Laboratory under controlled environmental conditions. The room temperature was maintained at 24 to 26 degrees. Humidity was maintained at 50 to 60 %. The light cycle period was 14 hours of day and 10 hours of night. The rats were given regular rat feeds along with supply of fresh water. The feed was a standard rat feed and was available ad libitum. Bedding changes were made twice weekly. Polypropylene cages were used to house the animals. A veterinary doctor was available to monitor the health of the rats. RESULTS: Both gross and histological examination failed to reveal the presence of any malignancy. Pre-cancerous conditions such as dysplasia also were not found in any of the tissues. The carcinogen used failed to induce any malignant changes in the tissues. CONCLUSIONS: In conclusion, the negative results of this study can be attributed to two Factors: a) The carcinogen used in the experiment was not a very potent carcinogen in terms of its carcinogenic effect on gastric tissues. b) It is possible that resistant laboratory animals (rat strains) have been bred which have shown resistance to the development of cancer induced by carcinogen. Mankind continues to struggle for survival in his war against cancer. Though extensive research has been done in the field of cancer science, both in its etiopathogenesis and also in its treatment, search for better and appropriate modalities of treatment continues. Some of them such as gastric cancer are silent killers and detected quite late. Preventive measures may be instituted in those that are at high risk or in those early pre-cancerous lesions have been detected. Finding preventive measures will go a long way in saving lives than finding a cure. Prevention is better than cure!
| Item Type: | Thesis (Masters) |
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| Uncontrolled Keywords: | Aspirin ; additive effect ; Vitamin C ; Gastric Tumours induced ; carcinogen (Nitrosopiperidine) ; Rats. |
| Subjects: | MEDICAL > General Surgery |
| Depositing User: | Devi S |
| Date Deposited: | 04 May 2018 04:05 |
| Last Modified: | 04 May 2018 04:05 |
| URI: | http://repository-tnmgrmu.ac.in/id/eprint/7433 |
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