[Morphometric assessment of rat lungs insufflated with liquid fixative at different pressures close to total lung capacity]. / Valoración morfométrica de pulmones de rata insuflados con líquido fijador a diferentes presiones próximas a la capacidad pulmonar total.

INTRODUCTION: Liquid lung fixing through the trachea to a pressure of 25 cmH2O is currently accepted to be ideal. However, some studies do not seem to confirm that assumption. MATERIAL AND METHODS: The lungs of Fischer rats were filled with fixing liquid to four different pressures: 20 cm, 25 cm, 30 cm and 35 cmH2O. The fixed lungs were processed for inspection under a light microscope for morphometric study. The following variables were recorded: lung volume, tissue volume, air volume, internal alveolar surface (IAS), alveolar chord to measure the size of the distal air space, and the number of alveoli. Statistical comparisons were performed. RESULTS: Lung volume increased with insufflation pressure, with significant differences related to pressure increases from 20 cm to 25 cm and from 30 cm to 35 cmH2O. Air volume did not change, although tissue volume changed when pressure increased from 20 cm to 30 cmH2O and from 30 cm to 35 cmH2O. The increase of tissue volume was related to extravasation of interstitial fixer. The number of alveoli increased with pressure from 20 to 30 cm and from 30 to 35 cmH2O. IAS increased with pressure from 20 cm and all the other pressures. Alveolar chord, which is related to size of alveoli, decreased significantly as pressure increased from 20 cm to 25 cm. CONCLUSION: A pressure of 25 cmH2O is ideal for liquid fixing of lung volumes. With lower pressures the lung is partially distended and with higher pressures the fluid can pass into the interstitial space.

Valoración morfométrica de pulmones de rata insuflados con líquido fijador a diferentes presiones próximas a la capacidad pulmonar total / The morphometric study of rat lungs after liquid-fixing to different pressures near total lung capacity

Introducción: En la actualidad se acepta que la fijación pulmonar con líquido fijador por vía traqueal a 25 cm de presión de H2O es la más idónea. Sin embargo, hay estudios que aparentemente no lo confirman. Material y métodos: Se ha utilizado ratas Fischer cuyos pulmones fueron insuflados con líquido fijador a cuatro diferentes presiones: 20, 25, 30 y 35 cmH2O. Los pulmones fijados se procesaron para microscopia de luz y se estudiaron morfométricamente. Se cuantificaron las siguientes variables: volumen pulmonar, volumen de tejido, volumen aéreo, superficie alveolar interna (SAI), cuerda alveolar, para medir el tamaño del espacio aéreo distal y número de alvéolos. Los resultados se compararon estadísticamente. Resultados: El volumen pulmonar aumentó con la presión de insuflación, siendo significativo al elevar la presión 20 a 25 cm y de 30 a 35 cmH2O. El volumen de aire no se modificó, pero sí el del tejido al incrementar la presión de 20 a 30 cmH2O y de 30 a 35 cmH2O. El aumento del volumen de tejido lo relacionamos con extravasación de líquido fijador al intersticio. El número de alvéolos aumentó con la presión siendo significativo al incrementar de 20 a 30 cm y de 30 a 35 cmH2O. La SAI aumentó con la presión siendo significativo entre 20 cm y el resto de los grupos. La cuerda alveolar, que está en relación con el tamaño de los alvéolos, disminuyó de tamaño con la presión siendo significativo al pasar de 20 a 25 cm. Conclusión: La presión de 25 cmH2O es la ideal para fijar los pulmones con líquido. Presiones inferiores distienden parcialmente el pulmón y presiones superiores pueden producir el paso de líquido al espacio intersticial. (AU)

Bronchial-associated lymphoid tissue (BALT) response to airway challenge with cigarette smoke, bovine antigen and anti-pulmonary serum.

The bronchial-associated lymphoid tissue (BALT) is a lymphoepithelial organ, related to the immune defence of the lung and to alveolar clearance, which changes size in certain states of disease. Changes in the size of BALT were quantified and compared, and Spearman's test was used to test the relation with the bronchial epithelium. A total of 180 rats were used, divided into 6 groups of 30 as follows: 1) untreated controls; 2) exposed to cigarette smoke for two months; 3) treated with anti-pulmonary serum three doses daily over five days; 4) exposed to cigarette smoke and treated with anti-pulmonary serum; 5) sensitized with bovine albumin and exposed to an environment containing this antigen for two months; 6) exposed to cigarette smoke and bovine albumin. The lungs were processed for histological study, and were stained with the PAS-Alcian blue method. The main left bronchi BALT was studied, and the following were quantified: Lymphatic area (LA), as a percentage of the lung surface occupied by BALT; the flat epithelium (FEp), as the length of bronchial epithelium anatomically related to LA, whose cells tend to adopt a flat shape; the Contact epithelium (Cep), as the length of bronchial epithelium which is in direct contact with the LA. A percentage count of bronchial cells was made in the following classifications: globet cells; globet cells stained with the PAS-Alcian blue method; flat cells; lymphoepithelium cells; columnar cells; and bronchial epithelium cells excluding the above two cell types.(ABSTRACT TRUNCATED AT 250 WORDS)

The modifications produced in allergic alveolitis and in Goodpasture's syndrome due to exposure to cigarette smoke.

Two groups of rats with experimental alveolitis were exposed to cigarette smoke. After comparing the results, the possible muffling effect of the cigarette smoke related to interstitial lung disease was discussed. 180 rats were divided into 6 groups of 30 animals each: Group 1: untreated controls; Group 2: exposed to cigarette smoke for 2 months; Group 3: sensitized with bovine albumin (BA) and exposed to an atmosphere with this antigen for two months, to reproduce a type of extrinsic allergic alveolitis (EAA); Group 4: treated with a single daily dose of anti-lung serum for three days followed by two days without treatment, to reproduce a type of Goodpasture's syndrome; Group 5: exposed to cigarette smoke and to BA; Group 6: exposed to cigarette smoke and treated with anti-lung serum. The animals were sacrificed and their lungs were treated for: Bronchoalveolar lavage (BAL), percentage lymphocyte count, polymorphonuclear (PMN) and alveolar macrophages (AM); semiquantitative and morphometric histological study. The semiquantitative study determined the area of the studied lung incision, affected by granulomae, increased alveolar aerial spaces, thickened alveolar walls and haemosiderine lung area. The morphometric study, based on the linear integration method, evaluated: the distance between two alveolar walls, the amount of interstice per field; and the number of AM with haemosiderine per field was counted. From the results we point out that the treated animals had significantly higher lymphocyte and BAL PMN counts than the untreated ones; no significant differences were found between the singly and doubly treated animals. The animals exposed to cigarette smoke and treated with anti-lung serum were those that showed the least number of lymphocytes and PMN of all the treated animals. The semiquantitative variables studied were all increased in comparison to the control group, most of the increases being significant. The morphometric variables revealed significant differences with respect to the untreated group, except for the animals which were treated with anti-lung serum and cigarette smoke, which showed a minimum decrease in the alveolar size and a slight increase of the interstitial tissue. Only one morphometric variable showed a significant difference between the group treated with anti-lung serum and the one treated with anti-lung serum and cigarette smoke: the number of AM with haemosiderine in the lung.(ABSTRACT TRUNCATED AT 400 WORDS)