Objective To explore the method for establishing a pig left lung orthotopic transplantation model. Methods A total of 4 male Yorkshire pigs weighing (40.0±2.5) kg underwent surgical procedures, including anesthesia, tracheal intubation, donor lung procurement, and recipient lung transplantation. Histological morphology and blood gas analysis of the transplanted lungs were assessed 2 hours after reperfusion to evaluate the histological changes and function of the transplanted lungs. Results The pigs underwent left lung in situ transplantation, effectively simulating conditions relevant to human lung transplantation. Two hours after the transplantation, arterial blood gas analysis showed that arterial partial pressure of oxygen was 155.4-178.6 mm Hg, arterial partial pressure of carbon dioxide was 53.1-62.4 mm Hg, and the oxygenation index was 310.8-357.2 mm Hg. Hematoxylin and eosin staining indicated a low degree of pulmonary edema and minimal cellular infiltration. Conclusion The pig left lung orthotopic transplantation model possesses strong operability and stability. Researchers can replicate this model according to the described methods and further conduct basic research and explore clinical translational applications.

Mice ; Animals ; Humans ; Disease Models, Animal

Objective Comparing the effects of steam sterilization on cyclic fatigue of stainless steel files. Meth-ods Fifty instruments of 25# stainless steel K files were randomly divided into 5 groups, which include 10 in each group. Group 1 was the blank control group, group 2 to 5 were subjected to 1, 3, 4, 5 steam sterilization cycles, then the files were tested by a custom-made device to assess cyclic fatigue and the number of cycles of failure (NCF) was calculated. Microstruc-ture of each file’s fracture surface was analyzed by Scanning Electron microscope (SEM). Results NCF in the 5 groups were 4 345.2 ± 384.2,3 937.9 ± 645.4,3 812.9 ± 532.5,3 626.2 ± 380.0,3 625.9 ± 565.6 respectively, and the differences among 5 groups were significantly different(F=2.598, P<0.05). After 4 or 5 times of steam sterilization, cyclic fatigue de-creased if compared with that in control group (P<0.05). Fracture surface in group 1 and group 2 was tough dimple structure and large numbers of regular, deep dimples were distributed on the surface. You could also see micro cavities clearly formed by fracture;Fracture surface in group 4 was dimple structure in brittle intergranular morphology. It is characterized by the presence of thin brittle precipitates, clean and smooth crystal interface, and a great sense of polyhedral stereo. Conclusion After 4 times of steam sterilization, cyclic fatigue strength of 25# stainless steel K files declined, which possessed the poten-tial risk of fracture.