Generating Cell or Tissue Transplants in Rats
The use of rats as cancer biology models began over a century ago. As the development of inbred strains progressed, combined with increasing knowledge about the influence of the immune system on animal models, the field of tumor transplantation models has become more and more refined. One of the advantages of rats is their larger size. For some types of investigations, the tissue size, surgical access to structures and locations, and for the benefit of visualization tools, make rat a superior model system to employ. Rats are extensively used in tissue transplantation studies for other biomedical research, and there is a body of knowledge and toolkit associated with that work that benefits cancer biology researchers as well.
Cell or Tissue Transplants
Many types of cells and solid tumor tissues have been used in rat experiments. The Nobel (Nb) rat prostate adenocarcinoma model has been used to study both primary and metastatic tumor biology, as has the AT-1 model. NeDe cells have been used as a model of metastatic kidney tumors. Various glioma models are used to tackle this challenging tumor type. Sarcoma tumor transplantations help to provide understanding of those rare tumors. Endometrial adenocarcinoma models exist as well. Esophageal solid tumor transplantation studies have been performed. Liver cancer models have been developed. Mammary carcinoma cell transplant model protocols have been established, including xenograft studies using human mammary cancer cells inoculated into rats.
An issue with rat models, as with mouse models, is that the immune response to transplanted tissues can greatly impact the studies. To address this, different strategies have been employed. Copenhagen immunocompetent rats are often used, as described in this model system of bone cancer. Athymic nude rats, cyclosporine treatment, or irradiation methods may be used to suppress immune system responses in rat transplantation experiments. In some experimental designs, rat cells may be placed into various mouse models with immune system variations.
Stem cells for treatments
As with mice, studies are demonstrating that rat stem cell transplantation may offer benefits for the treatment of cancer. Pursuing these strategies may yield important progress in the treatment of human cancers.