Elastin is known to occur in the lung parenchyma and pleura as well as in the pulmonary vessels, but no detailed studies of this elastin's linkage between them have been done in three dimensions. For many years we have known that there is abundant elastin in the mammalian lungs, which may be associated with etiology of causing emphysema. We have developed selective casting methods to allow us to determine the location where elastin is found morphologically. The method involves casting either the vasculature via the right ventricle, or the airways via the trachea in the air sacs. Studies of the vasculature were done with the lung inflated to 80% of the vital capacity. The casted lungs were then put in 0.1 N NaOH at 75 degrees C for 48 hours, turning them frequently. THis method removed all non-elastin tissues. The scanning electron microscopy (SEM) was used to reveal the three dimensional pictures of elastin structures from both lung parenchyma and pulmonary vessels. Elastin was seen as fenestrated sheets and some fibers in both the vessels and the airways. Elastin in the two different locations was often interconnected. Studies on 6 dogs, 8 rabbits, and 2 pigs showed no significant species difference at the level of resolution of the SEM, which was used to study the specimens after they had been freeze-dried.
Animal ; Blood Vessels/metabolism/ultrastructure ; Corrosion Casting ; Dogs ; Elastin/*ultrastructure ; Lung/blood supply/*metabolism ; Microscopy, Electron, Scanning ; Pulmonary Alveoli/metabolism/ultrastructure ; Rabbits ; Swine

OBJECTIVETo investigate the protective and therapeutic effects of pulmonary surfactant in the pathogenesis of chronic obstructive pulmonary disease (COPD) in hamsters.

METHODSCOPD animal model was established by smoke inhalations and intratracheal instillations of pancreatic elastase in hamsters. Ninty hamsters were divided into 9 groups as follows: normal group (N), two groups received smoke inhalations for 1 and 3 months (S1 and S3), one group received intratracheal instillation of surfactant (10 mg/100 g BW) for once after 1 month smoking (SP1), one group was treated with surfactant after 1.5, 2 and 2.5 months of smoking (SP3), and two groups received intratracheal administration of elastase (40 U/100 g BW) and were killed after 1 month and 3 months, respectively (E1 and E3). The surfactant was injected intratracheally after 1 week, 0.5, 1.0, 1.5, 2.0, and 2.5 months, followed by administration with elastase (EP1 and EP3). EP1 group were killed at the first month, and EP3 at the third month. Light microscopy and electromicroscopy observations were performed in each group. Pulmonary mean linear intercept (MLI), mean alveolar numbers (MAN), and pulmonary alveolar area (PAA) was measured by image analysis. The expression of surfactant protein A (SP-A) were observed by immunohistochemistry.

RESULTSSmoking for 3 months and instillations of elastase resulted in chronic bronchitis and emphysema. MLI and PAA increased and MAN decreased in all the experimental groups compared with in the normal group (P < 0.05 or P < 0.01). Administration of surfactant for 3 months resulted in statistically significant inhibition of pulmonary injury. MLI and PAA decreased and MAN increased in SP3 compared with in S3. Only MLI decreased in EP3 compared with E3. The expressions of SP-A in the type II alveolar epithelia decreased in S3 and E3 (compared with the normal group P < 0.01). After pulmonary surfactant intervention, the expression of SP-A increased significantly.

CONCLUSIONPulmonary surfactant may have a long-term protective effect on chronic smoking and elastase-induced COPD.

Animals ; Cricetinae ; Male ; Mesocricetus ; Pancreatic Elastase ; Pulmonary Alveoli ; ultrastructure ; Pulmonary Disease, Chronic Obstructive ; metabolism ; prevention & control ; Pulmonary Surfactant-Associated Protein A ; metabolism ; Pulmonary Surfactants ; therapeutic use ; Smoking

OBJECTIVEThis study examined the relationship between the ultrastructural alterations of alveolar epithelial cells type II (AEC-II) and pulmonary surfactant protein A (SP-A) levels in the lung tissue of young rats with acute lung injury (ALI) in order to explore the possible mechanism of ALI.

METHODSForty-eight young Sprague-Dawley rats were randomly divided into control and ALI groups. The rats in the ALI group were intraperitoneally injected with 4 mg/kg of lipopolysaccharide (LPS) in order to induce ALI. The control subjects were injected with the same volume of normal saline. Rats were sacrificed at 24, 48 and 72 hrs after LPS or NS injection. Lung samples were obtained from the lower parts of the left lung and fixed with 2.5% glutaraldehyde for transmission electron microscope examination and for Western blot test of SP-A.

RESULTSThe microvilli of AEC-II disappeared 24 hrs after LPS injection. After 24 and 48 hrs of LPS injection, lamellar body (Lb) increased in number, enlarged in size and reduced in density, and the ring-like arrangement of Lb was present. By 48 hrs after LPS injection, giant Lb with vacuole-like deformity appeared. The contents of lung SP-A in the ALI group 24 hrs (6.52+/-0.62 vs 5.02+/-0.35; P<0.01) and 48 hrs (6.65+/-0.62 vs 5.01+/-0.36; P<0.01) after LPS injection were significantly higher than those in the control group. By 72 hrs after LPS injection, Lbs ruptured and were reduced in number. The shape of the nuclei was irregular and the border was blurred. The content of lung SP-A was greatly reduced in the ALI group 72 hrs after LPS injection compared with that in the control group (3.87+/-0.50 vs 5.22+/-0.36; P<0.01).

CONCLUSIONSThe alterations of AEC-II and lung SP-A were time-dependent in young rats with ALI induced by LPS. In the early stage of ALI, the lung SP-A content showed a compensatory increase. With the increasing injury of AEC-II cells, the secretion of SP-A presented with a decompensation and the lung SP-A content decreased. This may be one possible mechanism for the development of ARD.

Animals ; Female ; Lipopolysaccharides ; toxicity ; Male ; Microscopy, Electron ; Pulmonary Alveoli ; pathology ; ultrastructure ; Pulmonary Surfactant-Associated Protein A ; analysis ; Rats ; Rats, Sprague-Dawley ; Respiratory Distress Syndrome, Adult ; metabolism ; pathology

OBJECTIVETo evaluate the capacity of active water and sodium transport of alveolar type II (AT II cells in rats with acute respiratory distress syndrome (ARDS).

METHODSAT II cells were isolated and purified from rats with ARDS, and the distribution of aquaporin-1 (AQP-1) on the cells was observed by immunocytochemistry, immunoelectron microscopy and Western blotting. The sodium currents were detected by patch-clamp technique in whole-cell recording mode.

RESULTSImmunocytochemistry showed staining for AQP-1 in rat AT II cells, and immunoelectron microscope demonstrated the presence of AQP-1, which was decreased as shown by Western blotting in comparison with the control group. The whole-cell currents were also decreased, but remained sensitive to terbutalin treatment.

CONCLUSIONSThe capacity of active water and sodium transport is damaged, but not totally lost in AT II cells of ARDS rats. Terbutalin can increase the currents even if in pathological conditions. AQP-1 and sodium transport of AT II cells play an important role in pulmonary liquid clearance.

Acute Disease ; Animals ; Aquaporin 1 ; metabolism ; Blotting, Western ; Cation Transport Proteins ; metabolism ; Immunohistochemistry ; Ion Transport ; Lung Diseases ; chemically induced ; metabolism ; Male ; Microscopy, Immunoelectron ; Oleic Acid ; Pulmonary Alveoli ; cytology ; metabolism ; ultrastructure ; Rats ; Rats, Sprague-Dawley ; Sodium ; metabolism ; Syndrome

We examined the ultrastructural features of the lung parenchyma and the expression of apoptosis of the respiratory cells by TUNEL technique. Male Sprague-Dawley rats (n=30) were intra-tracheally injected with cadmium (2.5 mg/kg) into both lungs. The light and electron microscopic features of the lung tissues were examined on Days 1, 3, 7 and 10 after the injection of cadmium. Specimen preparations for the light and electron microscopic TUNEL stains were performed. Ultrastructurally, on Days 1 and 3, the alveolar spaces were filled with edematous fluid, and desquamated type I epithelial cells. On Days 7 and 10, the alveolar spaces and interstitium were patchy infiltrated with young fibroblasts and some collagen deposition. The light microscopic TUNEL stain showed that apoptosis of the alveolar cells was most prominent on Day 1, and then the number of apoptosis was markedly decreased on Days 3, 7 and 10. The electron microscopic TUNEL stain showed the electron dense homogenous nuclear expression, and the formation of intra-nuclear blebs which protrude to the outside of nuclei. On Days 7 and 10, there are frequent apoptotic nuclear bodies in the alveolar macrophages. We could examine the identification of the equivocal apoptotic cells and various morphologic expression of apoptotic nuclei on the electron microscopic TUNEL stain.
Acetone/pharmacology ; Animals ; Apoptosis ; Cadmium/metabolism/*pharmacology ; Cell Nucleus/metabolism ; *In Situ Nick-End Labeling ; Lung/*cytology/*injuries/pathology/*ultrastructure ; Male ; Microscopy, Electron ; Microscopy, Electron, Scanning ; Pulmonary Alveoli/metabolism ; Rats ; Rats, Sprague-Dawley ; Support, Non-U.S. Gov't ; Time Factors

OBJECTIVESevere acute respiratory syndrome (SARS) is an emerging infectious disease that first manifested in humans in November 2002. The SARS-associated coronavirus (SARS-CoV) has been identified as the causal agent, but the pathology and pathogenesis are still not quite clear.

METHODSPost-mortem lung samples from six patients who died from SARS from April to July 2003 were studied by light and electron microscopy, Masson trichromal staining and immunohistochemistry. Evidence of infection with the SARS-CoV was determined by reverse-transcription PCR (RT-PCR) , serological examination and electron microscopy.

RESULTSFour of six patients had serological and RT-PCR evidence of recent infection of SARS-CoV. Morphologic changes are summarized as follows: (1) Diffuse and bilateral lung consolidation was seen in all patients (6/6) with increasing lung weight. (2) Diffuse alveolar damage was universal (6/6) with hyaline membrane formation (6/6), intra-alveolar edema/hemorrhage (6/6), fibrin deposition (6/6), pneumocyte desquamation (6/6). A marked disruption in the integrity of the alveolar epithelium was confirmed by immunostaining for the epithelial marker AE1/AE3 (6/6). (3) Type II pneumocytes, with mild hyperplasia, atypia, cytomegaly with granular amphophilic cytoplasm and intracytoplasmic lipid accumulation (5/6). (4) Giant cells in the alveoli were seen in five of 6 patients (5/6) , most of which were positive for the epithelial marker AE1/AE3 (5/6), but some cells were positive for the macrophage marker CD68(2/6). (5) A pronounced increase of macrophages were seen in the alveoli and the interstitium of the lung (6/6), which was confirmed by histological study and immunohistochemistry. (6) Haemophagocytosis was present in five of the 6 patients(5/6). (7) Lung fibrosis was seen in five patients(5/6), with alveolar septa and interstitium thickening(5/6), intraalveolar organizing exudates (6/6) and pleura thickening (4/6). Proliferation of collagen was confirmed by Masson trichromal staining, most of which was type III collagen by immunostaining. The formation of distinctive fibroblast/myofibroblast foci was seen in five patients (5/6) by light microscopy and immunochemistry. (8) Squamous metaplasia of bronchial mucosa was seen in five patients(5/6). (9) Thrombi was seen in all patients(6/6). (10) Accompanying infection was present in two patients, one was bacteria, the other was fungus. In addition, electron microscopy revealed viral particles in the cytoplasm of alveolar epithelial cells and endothelial cells corresponding to coronavirus.

CONCLUSIONDirect injury of SARS-CoV on alveolar epithelium, prominent macrophage infiltration and distinctive fibroblast/myofibroblast proliferation may play major roles in the pathogenesis of SARS.

Adult ; Antibodies, Monoclonal ; metabolism ; Antigens, CD ; metabolism ; Antigens, Differentiation, Myelomonocytic ; metabolism ; Epithelium ; pathology ; Female ; Humans ; Keratins ; immunology ; Lung ; pathology ; ultrastructure ; virology ; Male ; Middle Aged ; Pulmonary Alveoli ; pathology ; Pulmonary Fibrosis ; etiology ; pathology ; SARS Virus ; isolation & purification ; Severe Acute Respiratory Syndrome ; complications ; metabolism ; pathology ; virology