The rat is a poor animal model for the study of human pulmonary hypertension.

The pulmonary circulation of the rat is widely used as an animal model for studies of human pulmonary hypertension. It is not difficult to understand its appeal. The species is a small laboratory animal which is readily accommodated in decompression chambers for studies for simulated high altitude. It is also very susceptible to the action of the metabolites of pyrrolizidine alkaloids which rapidly lead to severe pulmonary vascular disease in the absence of intrinsic heart and lung disease, thus suggesting its value as an animal model of primary pulmonary hypertension. However, these obvious advantages of the rat pulmonary circulation are outweighed by the fact that its pathological reactions to hypoxia and noxious dietary agents differ significantly from those found in human disease. This can lead to erroneous conclusions as to the nature of the remodelling of the human pulmonary vasculature in pulmonary hypertension.