Lung regeneration by fetal lung tissue implantation in a mouse pulmonary emphysema model

The mortality and morbidity of chronic obstructive pulmonary disease are high. However, no radical therapy has been developed to date. The purpose of this study was to evaluate whether fetal mouse lung tissue can grow and differentiate in the emphysematous lung. Fetal lung tissue from green fluorescent protein C57BL/6 mice at 16 days' gestation was used as donor material. Twelve-month-old pallid mice were used as recipients. Donor lungs were cut into small pieces and implanted into the recipient left lung by performing thoracotomy under anesthesia. The recipient mice were sacrificed at day 7, 14, and 28 after implantation and used for histological examination. Well-developed spontaneous pulmonary emphysema was seen in 12-month-old pallid mice. Smooth and continuous connection between implanted fetal lung tissue and recipient lung was recognized. Air space expansion and donor tissue differentiation were observed over time. We could clearly distinguish the border zones between injected tissue and native tissue by the green fluorescence of grafts. Fetal mouse lung fragments survived and differentiated in the emphysematous lung of pallidmice. Implantation of fetal lung tissue in pallid mice might lead to further lung regeneration research from the perspective of respiratory and exercise function.