Establishment of an Experimental Intrapulmonary Tumor Nodule Model

Background. A pulmonary tumor model is necessary to study the biology and therapy of lung cancer. Methods to establish a solitary intrapulmonary nodule are not well defined. Two methods for solitary intrapulmonary tumor nodule development in the Fischer rat are described. Methods. Methylcholanthrene-induced sarcoma cell suspensions were introduced into lung parenchyma of Fischer rats via limited thoracotomy and lung puncture, or instilled into a distal airway after tracheal puncture and catheterization. Intrapulmonary tumor location, implantation mortality, procedure length, and animal survival were recorded. Results. Single pulmonary nodules developed at the implanted position in 100% (n = 320) and 95% (62/65) of animals after direct injection into the pulmonary parenchyma or via tracheal puncture and instillation. Operative mortality was 2% and 5% via lung or tracheal implantation, respectively. Less than 5 minutes was required for each implantation. Mean survival time was 24 ± 2 and 26 ± 6 days after lung or tracheal implantation in animals allowed to survive until tumor-induced death. Conclusions. These easily performed, reproducible methods of establishing solitary intrapulmonary tumors are useful tools for lung cancer research.