OBJECTIVETo investigate the expression patterns of surfactant protein B (SP-B) and its role in the development of human fatal lung epithelial cells.

METHODSHuman fetal lung tissues were obtained from 37 fetuses of 10-34 weeks at abortion with parental consent and from two newborn infants who died of non-pulmonary causes. SP-B expression in the lung tissues was examined by immunohistochemistry.

RESULTSSP-B was detected in the cytoplasm of nonciliated columnar epithelial cells of the human fetal lung in as early as the 16th week of gestation. The positive reaction of SP-B was enhanced during canalicular stages and was more intense in the distal than in the proximal airway epithelium. From the 25th week to the prenatal stage, SP-B expression underwent no significant changes in the primitive alveolar stage, but increased remarkably after birth.

CONCLUSIONThe expression and secretion of SP-B reflects the maturation of the epithelial cells in human fatal lungs, and may closely associate with the survival ability of the newborn infants.

Cell Survival ; physiology ; Cells, Cultured ; Epithelial Cells ; cytology ; metabolism ; Fetus ; Humans ; Infant, Newborn ; Lung ; Pulmonary Alveoli ; cytology ; metabolism ; Pulmonary Surfactant-Associated Protein B ; biosynthesis ; physiology

To establish a better method of primary culture for alveolar epithelial type II cells (AEC II) and to study its bionomics, alveolar epithelial type II cells were isolated by digestion with trypsin and collagenase, which were then purified by plated into culture flask coated with rat immunoglobulin G. The purified AEC II were identified by alkaline phosphatase staining, electron microscopy, immunocytochemical staining of pulmonary surfactant protein A (SPA). The SPA expression and transfection characteristics were compared with those of A549 cell line. The results showed that AEC II could be isolated by digestion with trysin and collagenase and purified by adhesive purification by using IgG, with a yield of about 2-3 x 10(7), and a purity of about 75%-84%. Cells could be quickly identified with AKP staining. AEC II were different from A549 cell line in terms of SPA expression and transfection characteristics. It is concluded that adhesive purification with IgG can improve the purity of AEC II, and AKP staining is simple in cell identification. AEC II can not be completely replaced by A549 cells in some studies because the differences between them, such as SPA expression.
Cell Culture Techniques/*methods ; Cell Separation/*methods ; Cells, Cultured ; Ecology ; Epithelial Cells/*cytology ; Immunoglobulin G/pharmacology ; Pulmonary Alveoli/*cytology ; Pulmonary Surfactant-Associated Protein A/biosynthesis ; Rats, Wistar

OBJECTIVETo explore dysfunction mechanism of rat alveolar type II (AT-II) injured by bleomycin (BLM).

METHODSSD rats were injected with a single intratracheal dose of bleomycin or control saline. On day 7, 14, and 28 following intratracheal bleomycin or saline instillation, animals were killed under overdose of 1.5% sodium pentobarbital (0.25 ml/100 g, i.p.) and bronchoalveolar lavage fluid (BALF) from the lung was tested for the activity of pulmonary surfactant (PS) by the Whihelmy Film Balance. Several concentrations of bleomycin stimulated the culture of rat AT-II cells, and surfactant protein (SP) A, B, and aquaporin-1 (AQP) mRNA were analyzed by fluorescent quantitative polymerase chain reaction (FQ-PCR).

RESULTSThe activity of PS and hypoxemia significantly decreased on day 7 and improved on day 14 and completely recovered to normal status on day 28. SP-A, B, and AQP-1 mRNA expression in BLM-stimulated group were significantly lower than those in the control group (P<0.001).

CONCLUSIONBLM-injured AT-II cells decrease the levels of SP-A, B, and AQP-1 mRNA and cause PS dysfunction, resulting in hypoxemia and pneumonedema.

Animals ; Aquaporin 1 ; biosynthesis ; genetics ; Bleomycin ; administration & dosage ; toxicity ; Cells, Cultured ; Dose-Response Relationship, Drug ; Epithelial Cells ; drug effects ; metabolism ; Hypoxia ; chemically induced ; metabolism ; pathology ; Male ; Pulmonary Alveoli ; cytology ; drug effects ; Pulmonary Surfactant-Associated Protein A ; biosynthesis ; genetics ; Pulmonary Surfactant-Associated Protein B ; biosynthesis ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Time Factors

OBJECTIVETo investigate the influence of ambroxol on paraquat poisoning induced acute lung tissue injury and the change of pulmonary surfactant associated protein A in the experimental rats.

METHODSOne hundred and twenty healthy adult male Sprague-Dawley rats were randomizedly assigned into normal saline (NS) group (n = 24), paraquat poisoning induced lung tissue injury model (PQ) group (n = 48) and ambroxol treatment (AT) group (n = 48). The indexes were observed among the three groups comprising the mortality rate, the change of arterial blood PaCO(2) and PaO(2), the ratio of wet to dry lung tissue (W/D), the change of the lung tissue under light and electric microscope respectively, and the expression of pulmonary surfactant associated protein A.

RESULTSThe mortality rate of rats in the PQ group was 50.0% on the seventh day while the mortality rate in the AT group was 25.0%. The level of arterial blood PaCO(2) in the PQ group (6.94 +/- 0.8) kPa was significantly higher than that in the AT group (6.12 +/- 0.5) kPa and the NS group (4.6 +/- 0.4) kPa. The level of arterial blood PaO(2) in the PQ group (6.98 +/- 1.1) kPa was significantly lower than that in the AT group (8.25 +/- 0.7) kPa and the NS group (12.7 +/- 0.8) kPa. There were significant differences among the groups (P < 0.05). The degree of lung tissue injury was severe in PQ group and relieved in AT group. The expression of pulmonary surfactant associated protein A was significantly decreased in PQ group 13.22% +/- 2.21% on the seventh day, compared with that in the AT group (21.82% +/- 3.67%) (P < 0.05). The expression of pulmonary surfactant associated protein A in AT group was significantly higher in the AT group (18.97% +/- 0.91%) than that in the PQ group on the seventh day (P < 0.05).

CONCLUSIONAmbroxol plays a role in facilitating synthesis and secretion of pulmonary surfactant protein A and relieves the lung tissue injury induced by paraquat poisoning.

Ambroxol ; pharmacology ; Animals ; Immunohistochemistry ; Lung ; metabolism ; pathology ; Male ; Paraquat ; poisoning ; Pulmonary Surfactant-Associated Protein A ; biosynthesis ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Respiratory Distress Syndrome, Adult ; chemically induced ; metabolism ; pathology

In order to confirm the alteration and significance of cigarette smoke exposure on SP-A in rats, 20 Wistar rats were assigned randomly to two groups: an N group (n=10), and an S group (n=10). The ultra-structural change was observed by electron microscopy. The number of cells positive for SPA was by immunohistochemically measured. The mRNA expression in the lung tissues was determined by reverse transcription polymerase chain reaction (RT-PCR). The number of cells positive for SPA of the S group (0.52 +/- 0.05) was lower than that of the N group (0.72+/-0.06) (P<0.05). The levels of mRNA of SPA in the lung tissues of the S group (0.3522+/-0.0512) was significantly lower than that of the N group (0.4432+/-0.05628) (P<0.05). It is concluded that cigarette smoke alone decreased the level of SP-A and that might have an important effect on surfactant metabolism and the host defense functions of surfactant in the peripheral airways, which might play a crucial role in the development of chronic obstructive lung disease.
Gene Expression Regulation ; Immunohistochemistry/methods ; Lung/metabolism ; Microscopy, Electron ; Pulmonary Surfactant-Associated Protein A/*biosynthesis ; RNA, Messenger/metabolism ; Rats, Wistar ; Reverse Transcriptase Polymerase Chain Reaction ; Smoking/*adverse effects ; Tobacco Smoke Pollution/*adverse effects