The effects of retinoic acid on the growth of residue lung after pneumonectomy in rats

SUMMARY:The effects of retinoic acid on the growth of residue lung after pneumonectomy in rats.Dr. Bekir Sami Karapolat, University of Dokuz Eylul, Faculty of Medicine, Departmentof Thoracic Surgery, Izmir, Turkey.Objective: Pneumonectomy is common and important operation in thoracic surgery. Thedecision to perform pneumonectomy often creates a problem both for the patient and surgeon.This is because there is always the probability that the remaining lung tissue may not besufficient for the patient though the patients are evaluated well from the point of respirationpreoperatively. The growth of lung tissue volume and function is a desirable conditionpostoperatively. Many of agents have been used for this growth. Retinoic acid may form one ofthese drugs, and normally plays a part in the foetal maturation of lung tissue. In this study, weinvestigated that effect of retinoic acid which administered exogenically in the growth ofopposite lung after pneumonectomy.Materials and methods: 21 adult male Wistar albino rats from the same colony were used.They were divided three groups as Group A, B and C. Group A is a sham group and undergoneonly left posterolateral thoracotomy. In Group B and C, the rats were subjected to leftposterolateral thoracotomy and left pneumonectomy. No drug treatment was applied to GroupA and B. In Group C, rats were administered intraperitoneal Retinoic acid (0.5 microgram / gr)during the operation and the same dosage was continued to be given everyday postoperatively.Rats were sacrificed on the 10th day and their total body and right lung weights were measured.The lung tissues were examined histopathologically. The volume and weight of the lung werecompared with the body weight before sacrifice, and the lung weight and volume indices werecalculated. The results were evaluated statistically.Findings: In the volume and weight of the residual lung in the retinoic acid administered groupat the end of the study were found a more increase in Group B in comparison with Group A,and the Group C in comparison with the other two groups. The volume and weight indices ofthe lung were found to be higher in Group B in comparison with Group A, and in Group C incomparison with Groups A and B. A significant rise on size and volume of the alveolarstructure of lung tissue was determined in Group C histopathologically.Results: Retinoic acid contributes to the compensatory growth of the residual lung tissue afterpneumonectomy. The usage of Retinoic acid may lead to increases that can create positiveresults in the functional capacities in pneumonectomy patients.6