OBJECTIVE: To develop a lung tumor model in rats using Walker’s carcinosarcoma and to verify the presence in vivo of tumors using computerized tomography (CT). METHODS: Female Wistar rats (n=47) were anesthetized with pentobarbital, intubated through tracheostomy and submitted to thoracotomy; subsequently a 50-70 mu L volume containing Walker’s tumor cells, or the suspension of these same cells, was injected into the lung parenchyma. The study consisted of two phases: in the first a tumor implantation technique was developed and the number of cells required to attain a satisfactory tumor development rate was established. In the second phase, the tumor volume in cm³ (Dxd²/2) was determined through CT scan and necropsis, and the survival rates were analyzed. RESULTS: The overall tumor development rate was 93.3%, or rather, 81.1% in the first phase and 100% in the second. The surgical mortality rate was 17.0%. The average tumor volume was similar (0.099 vs. 0.111 cm³) at CT scan and at necropsis, respectively (r=0.993; p<0.0001). The survival average was about 10 days. CONCLUSION: The high tumor development rate observed and the close correlation between the figures obtained through CT scan and necropsis allow for tomographical tumor growth monitoring and thereby for evaluation of the action of anti-tumor drugs in vivo as well as for analysis of survival rates without the need for sacrificing animals.
Lung tumor model; Walker’s carcinosarcoma; Experimental tumor