Abstract
OBJECTIVE: We investigated and compared the long-term (6-month) histologic changes in a rat model of sublobar resection created using electrocautery or stapler techniques. METHODS: Nine-week-old male rats were anesthetized and intubated; thoracotomy with sublobar resection was performed in the right middle lobe using electrocautery or stapler techniques. Histological examination was performed at 2, 4, 8, 12, and 24 weeks post-surgery to assess long-term effects on lung tissue repair and morphologic changes. Lung expansion and alveolar epithelial cell proliferation were evaluated by measuring the mean linear intercept and counting the number of alveolar type I and II cells. RESULTS: The electrocautery group showed signs of lung self-repair at the resected area over time, with inflammatory cell infiltration followed by growth of vessels and bronchioles. Mesothelial cells covered the resected area by 2 weeks; elastic fibers gradually connected from both sides by 24 weeks. Lung expansion, measured by mean linear intercept, was initially small below the electrocautery resection area at 2 weeks but recovered from 4 to 24 weeks. The stapler group showed persistently small mean linear intercept over time. In the electrocautery group, the number of alveolar type II cells was higher just below the resection than in other areas from 2 to 24 weeks, followed by alveolar type I cells (4 to 24 weeks). The stapler group showed a transient alveolar type II cell increase at 2 weeks. CONCLUSIONS: Compared to the stapler technique, electrocautery may provide advantages for postoperative lung repair by promoting lung expansion and alveolar epithelial cell proliferation.