Animal Models for Colorectal Cancer

Abstract

Introduction: Colorectal cancer is a very frequent sort of neoplasm among the population, with a high mortality rate. It develops from an association of genetic and environmental factors, and it is related to multiple cell signaling pathways. Cell cultures and animal models are used in research to reproduce the process of disease development in humans. Of the existing animal models, the most commonly used are animals with tumors induced by chemical agents and genetically modified animals. Objective: To present and synthesize the main animal models of colorectal carcinogenesis used in the research, comparing its advantages and disadvantages. Method: This literature review was performed through the search for scientific articles over the last 18 years in PubMed and Science Direct databases, by using keywords such as “animal models”, “colorectal carcinogenesis” and “tumor induction”. Results: 1,2-dimethylhydrazine and azoxymethane are carcinogenic agents with high specificity for the small and large intestine regions. Therefore, the two substances are widely used. Concerning the genetically modified animal models, there is a larger number of studies concerning mutations of the APC, p53 and K-ras genes. Animals with the APC gene mutation develop colorectal neoplasms, whereas animals with p53 and K-ras genes mutations are able to potentiate the effects of the APC gene mutation as well as the chemical inducers. Conclusion: Each animal model has advantages and disadvantages, and some are individually efficient as to the induction of carcinogenesis, and in other cases the association of two forms of induction is the best way to obtain representative results of carcinogenesis in humans.

Omeprazole and adenocarcinoma in the stomach of rats submitted to duodenogastric reflux. Is there a protective effect?

“…Therefore, nitrites are the active ingredient and nitrates serve as reservoirs that supply nitrites. There are numerous epidemiological studies that associate the potential risk of gastric cancer and other cancers with the intake of nitrates, nitrites and nitrosamines in the diet 15,17,[19][20][21] .…”

“…In recent decades, most experimental studies have been carried out on mammals, due to their similarities with humans, in many ways. The conclusions of studies on animals, respecting ethical aspects, cannot be fully transposed to humans 18,20 . The results of this study again confirmed that the lesions are due to the presence of duodenogastric reflux.…”

The role of mouse models in colorectal cancer research—The need and the importance of the orthotopic models

“…Each animal model has its pros and cons—Table 1, and in some cases, association of more than one form in CRC induction is necessary . The model should be chosen accordingly to the study expectations and aim, maximizing its potential …”

Changes in the spleen white pulp in the offspring of splenectomized rats of various ages exposed to 1,2-dimethylhydrazine

“…Его используют для моделирования рака толстой кишки у лабораторных животных [3,4]. Эта модель достаточно изучена [5][6][7], она в отличие от клеточных культур позволяет воспроизводить опухолевый ангиогенез и метастазирование [8]. Известно, что опухоль, растущая под действием ДМГ, приводит к развитию акцидентальной инволюции тимуса [9], а также к морфологическим изменениям в органах эндокринной системы [10].…”