Development of bronchiolar epithelium in rats

1986 ◽  
Vol 250 (5) ◽  
pp. R783-R788 ◽  
Author(s):  
G. D. Massaro ◽  
D. Massaro
Keyword(s):  
Secretory Granules ◽  
Perinatal Period ◽  
Volume Density ◽  
Clara Cell ◽  
Numerical Density ◽  
Clara Cells ◽  
Ciliated Cells ◽  
Bronchiolar Epithelium ◽  
Conducting Airways

We used ultrastructural and morphometric means to examine aspects of the regulation of the maturation of rat bronchiolar Clara cells and the development of the epithelium of small conducting airways in the perinatal period. We found the nuclear numerical density per cubed centimeter (Nvn) of Clara cells fell and the Nvn of ciliated cells increased from birth to age 60 days, the prenatal administration of a glucocorticosteroid (dexamethasone) to dams caused a 35% decrease in the Nvn of ciliated cells present at birth but did not alter the Nvn of Clara cells, the administration of dexamethasone to pups from postnatal days 1 to 6 did not alter the Nvn of bronchiolar Clara or ciliated cells present at age 7 days but did diminish the total number of lung cells as assessed by measurements of lung DNA, the administration of dexamethasone to dams from gestation days 18 to 20 or from gestation days 20 to 22 did not alter the volume density of Clara cell glycogen, secretory granules, rough endoplasmic reticulum, or mitochondria of pups at gestation day 21.5 or on the day of birth, and glucagon, epinephrine, and 8-bromoadenosine 3',5'-cyclic monophosphate resulted in a decrease of Clara cell glycogen when individually incubated in vitro for 4 h with bronchiolar tissue from rat fetuses 21.5 days of age.

Brief perinatal hypoxia impairs postnatal development of the bronchiolar epithelium

1989 ◽  
Vol 257 (2) ◽  
pp. L80-L85 ◽  
Author(s):  
G. D. Massaro ◽  
J. Olivier ◽  
D. Massaro
Keyword(s):  
Secretory Granules ◽  
Volume Density ◽  
Clara Cell ◽  
Lower Percentage ◽  
Numerical Density ◽  
Perinatal Hypoxia ◽  
Clara Cells ◽  
Ciliated Cells ◽  
Pregnant Rats ◽  
Bronchiolar Epithelium

We placed pregnant rats in 10% O2 on the last day of gestation for less than or equal to 9 h plus 1-2 h (with their pups) after the onset of delivery. In the pups this brief perinatal hypoxia led to an altered cellular composition of the bronchiolar epithelium that persisted at least to age 30 days; it was characterized by a higher nuclear numerical density (Nvn) of Clara cells, a lower Nvn of ciliated cells, and a lower percentage and Nvn of Clara cells in mitoses compared with control rats. The perinatal hypoxia also led to a significantly lower volume and volume density of the secretory apparatus (rough endoplasmic reticulum and secretory granules) on day 7 in 10% O2-born rats. The data on the Nvn of Clara and ciliated cells and on Clara cell mitoses are consistent with the notion that exposure to 10% O2 impaired the differentiation of Clara cells into ciliated cells and this impairment persisted well beyond the period of exposure.

Hyperoxia reversibly suppresses development of bronchiolar epithelium

1986 ◽  
Vol 251 (6) ◽  
pp. R1045-R1050
Author(s):  
G. D. Massaro ◽  
L. McCoy ◽  
D. Massaro
Keyword(s):  
Normal Development ◽  
Secretory Granules ◽  
Ciliated Cell ◽  
Volume Density ◽  
Clara Cell ◽  
Numerical Density ◽  
Clara Cells ◽  
Ciliated Cells ◽  
Newborn Rats ◽  
Bronchiolar Epithelium

The bronchiolar epithelium of rats is anatomically immature at birth. We now ask whether postnatal hyperoxia impairs the normal development of bronchiolar epithelium; and, if development is impaired, is the impairment permanent? To answer these questions, we exposed newborn rats to hyperoxia (greater than 95% O2, 1 atm) or air for 7 days and killed the rats at age 7 or 30 days. We used ultrastructural and morphometric means to assess maturation of the bronchiolar epithelium. Hyperoxia substantially diminished the postnatal increase in nuclear numerical density of bronchiolar Clara cells and ciliated cells. Hyperoxia also markedly delayed the rise in volume density of Clara cell secretory granules and rough endoplasmic reticulum but accelerated the increase in volume density of Clara and ciliated cell mitochondria. When rats exposed to hyperoxia from age 1 to 7 days were thereafter allowed to breathe air, by age 30 days all the differences were eliminated that were detected between the air- and O2-breathing groups at age 7 days. We conclude hyperoxia causes a marked but nonpermanent suppression of maturation of the bronchiolar epithelium.

Postnatal undernutrition slows development of bronchiolar epithelium in rats

1988 ◽  
Vol 255 (4) ◽  
pp. R521-R526 ◽  
Author(s):  
G. D. Massaro ◽  
L. McCoy ◽  
D. Massaro
Keyword(s):  
Small Airway ◽  
Numerical Density ◽  
Clara Cells ◽  
Ciliated Cells ◽  
Long Term Effects ◽  
Chronic Lung Diseases ◽  
Airway Function ◽  
Childhood Environment ◽  
Bronchiolar Epithelium ◽  
Morphological Maturation

The lung's small conducting airways are sites of dysfunction early in the course of chronic lung diseases that are prevalent in humans; furthermore, there is evidence that aspects of childhood environment may adversely influence small airway function in adulthood. Because there is considerable early postnatal morphological maturation of the bronchiolar epithelium in rats, these considerations led to the present study in which we assessed the effect of early postnatal undernutrition in rats on the anatomic development of the bronchiolar epithelium. We found undernutrition, produced by increasing rat litter size shortly after birth, led to delayed development of the mitochondria and rough endoplasmic reticulum of bronchiolar Clara cells. Of particular interest, underfeeding resulted in considerably diminished mitosis by Clara cells, decreased nuclear numerical density of bronchiolar ciliated cells, evidence of diminished conversion of Clara cells to ciliated cells, and an abnormal cellular composition of the small airway epithelium that persisted well beyond the period of underfeeding. We conclude that early neonatal events can have long-term effects on the bronchiolar epithelium.

Immunolocalization of glutathione S-transferase isoenzymes in bronchiolar epithelium of rats and mice

1994 ◽  
Vol 267 (6) ◽  
pp. L766-L774 ◽  
Author(s):  
M. J. Lee ◽  
D. Dinsdale
Keyword(s):  
Secretory Granules ◽  
Clara Cell ◽  
Lung Cells ◽  
Clara Cells ◽  
Glutathione S Transferase ◽  
Interspecies Differences ◽  
Glutathione S Transferases ◽  
Bronchiolar Epithelium ◽  
Rats And Mice ◽  
Intracellular Compartmentalization

Ultrastructural immunocytochemistry, using antisera raised against specific subunits of glutathione S-transferases, indicated differences in the intracellular compartmentalization of these enzymes in the bronchiolar epithelia of rats and mice. Antisera raised against subunits of the alpha-class derived from both rats (Ya) and mice (Yc) labeled secretory granules in Clara cells of rats, but not mice, and they also labeled mitochondria throughout murine bronchioles. In contrast, antiserum to a mu-class subunit derived from rats (Yb1) did not result in any labeling over the Clara cell granules of rats but produced intense labeling over those of mice. Antiserum raised against a rat-derived pi-class subunit (Yp) did not label Clara cell granules or mitochondria in either rats or mice but produced a slight concentration of label over the nuclei of murine cells. Variations in the distribution of glutathione S-transferases may contribute to interspecies differences in the sensitivity of particular lung cells to toxins. Isoenzymes of glutathione S-transferase, secreted into the bronchioles of rats and mice, may help to protect the epithelium from extracellular toxins.

Development of bronchiolar epithelium: time course of response to oxygen and recovery

1988 ◽  
Vol 254 (5) ◽  
pp. R755-R760 ◽  
Author(s):  
G. D. Massaro ◽  
L. McCoy ◽  
D. Massaro
Keyword(s):  
Time Course ◽  
Clara Cell ◽  
Numerical Density ◽  
Clara Cells ◽  
Cell Organelles ◽  
Early Postnatal Development ◽  
Bronchiolar Epithelium ◽  
Normal Increase ◽  
Cell Mitosis ◽  
Second Peak

Hyperoxia (greater than 95% O2) reversibly suppresses the early postnatal development of rat bronchiolar epithelium. We now show that blunting of the normal increase in nuclear numerical density per centimeter cubed of Clara and ciliated cells becomes apparent within 24 h of exposure to O2 (age 2 days) and reaches a maximum on the last day of hyperoxia (age 7 days). The intergroup differences began to disappear within 48 h after removal from O2. During air breathing, Clara cell mitosis increased sixfold between the ages of 1 and 2 days and returned to day 1 values by age 7 days. During O2 breathing, Clara cell mitosis increased threefold between age 1 and 2 days, returned to day 1 values by day 4, but exhibited a second peak 24 h post-O2 (day 8) not present in unexposed pups. The onset of differences in the volume of Clara cell organelles and glycogen was variable, but the differences were partly or completely eliminated 48 h post-O2 exposure. We conclude hyperoxia reversibly impairs mitosis by Clara cells.

Postnatal development of the bronchiolar Clara cell in rats

1984 ◽  
Vol 247 (3) ◽  
pp. C197-C203 ◽  
Author(s):  
G. D. Massaro ◽  
L. Davis ◽  
D. Massaro
Keyword(s):  
Endoplasmic Reticulum ◽  
Secretory Granules ◽  
Volume Density ◽  
Clara Cell ◽  
Clara Cells ◽  
Glycogen Depletion ◽  
Postnatal Maturation ◽  
Maternal Undernutrition ◽  
Fetal Rats ◽  
Ad Libitum

We studied aspects of perinatal rat bronchiolar Clara cell development. We found that the volume density (Vv) of glycogen areas decreased 10-fold between postnatal days 1 and 2 and that the Vv of secretory granules, rough endoplasmic reticulum (RER), and mitochondria increased markedly during the 1st postnatal wk. Compared with pups of dams allowed food ad libitum during gestation, pups from dams underfed during gestation had a higher Vv of glycogen areas for the first 2 postnatal days but a lower Vv of secretory granules and RER for the time studied (to age 7 days). Glucagon injected, in utero, into fetal rats at 21.5 days of gestation resulted in a 40% decrease in the Vv of the glycogen areas within 4 h. We conclude that 1) bronchiolar Clara cells are immature at birth and undergo marked early postnatal maturation, 2) prenatal events (maternal undernutrition) affect postnatal maturation of the Clara cells, and 3) exogenous glucagon leads to glycogen depletion in Clara cells of fetal rats of 21.5 days gestation.

Bromobenzene causes Clara cell damage in mice

1985 ◽  
Vol 63 (11) ◽  
pp. 1480-1484 ◽  
Author(s):  
P. G. Forkert
Keyword(s):  
Cell Damage ◽  
Cellular Damage ◽  
Clara Cell ◽  
Halogenated Hydrocarbons ◽  
Clara Cells ◽  
Ciliated Cells ◽  
Tubular Aggregates ◽  
Cytoplasmic Matrix ◽  
Pulmonary Lesions ◽  
Bronchiolar Epithelium

The oral administration of a single dose of bromobenzene (5 mmol/kg) causes cellular damage in the lungs of C57B1/6 male mice. At 24 h following treatment with bromobenzene. Clara cells of the bronchiolar epithelium demonstrated necrosis; endoplasmic reticular cisternae were extensively dilated, and degenerated membranes were present in the cytoplasmic matrix as electron-dense tubular aggregates. The ciliated cells which were interspersed among the Clara cells, remained unaffected. The morphologic alterations produced by bromobenzene and the target cell are similar in character to the pulmonary lesions produced by administration of other aromatic and aliphatic halogenated hydrocarbons.

Differential susceptibilities of isolated hamster lung cell types to amiodarone toxicity

1998 ◽  
Vol 76 (7-8) ◽  
pp. 721-727 ◽  
Author(s):  
M W Bolt ◽  
W J Racz ◽  
J F Brien ◽  
T M Bray ◽  
T E Massey
Keyword(s):  
Alveolar Macrophages ◽  
Gradient Centrifugation ◽  
Cell Types ◽  
Clara Cell ◽  
Blue Dye ◽  
Alveolar Type ◽  
Specific Cell ◽  
Type Ii ◽  
Clara Cells

Treatment of cardiac dysrhythmias with the iodinated benzofuran derivative amiodarone (AM) is limited by pulmonary toxicity. The susceptibilities of different lung cell types of male Golden Syrian hamsters to AM-induced cytotoxicity were investigated in vitro. Bronchoalveolar lavage and protease digestion to release cells, followed by centrifugal elutriation and density gradient centrifugation, resulted in preparations enriched with alveolar macrophages (98%), alveolar type II cells (75-85%), and nonciliated bronchiolar epithelial (Clara) cells (35-50%). Alveolar type II cell and Clara cell preparations demonstrated decreased viability (by 0.5% trypan blue dye exclusion) when incubated with 50 µM AM for 36 h, and all AM-treated cell preparations demonstrated decreased viability when incubated with 100 or 200 µM AM. Based on a viability index ((viability of AM-treated cells ÷ viability of controls) × 100%), the Clara cell fraction was significantly (p < 0.05) more susceptible than all of the other cell types to 50 µM AM. However, AM cytotoxicity was greatest (p < 0.05) in alveolar macrophages following incubation with 100 or 200 µM AM. There was no difference between any of the enriched cell preparations in the amount of drug accumulated following 24 h of incubation with 50 µM AM, whereas alveolar macrophages accumulated the most drug during incubation with 100 µM AM. Thus, the most susceptible cell type was dependent on AM concentration. AM-induced cytotoxicity in specific cell types may initiate processes leading to inflammation and pulmonary fibrosis.Key words: amiodarone, susceptibility, alveolar macrophage, accumulation.

scholarly journals Immunolocalization of Sonic Hedgehog (Shh) in Developing Mouse Lung

2001 ◽  
Vol 49 (12) ◽  
pp. 1593-1603 ◽  
Author(s):  
Leigh-Anne D. Miller ◽  
Susan E. Wert ◽  
Jeffrey A. Whitsett
Keyword(s):  
Epithelial Cells ◽  
Sonic Hedgehog ◽  
Normal Development ◽  
Clara Cell ◽  
Mouse Lung ◽  
Lung Hypoplasia ◽  
Hepatocyte Nuclear Factor ◽  
Clara Cells ◽  
Lung Morphogenesis ◽  
Conducting Airways

Expression of sonic hedgehog (Shh) is required for normal development of the lung during embryogenesis. Loss of Shh expression in mice results in tracheoesophageal fistula, lung hypoplasia, and abnormal lung lobulation. To determine whether Shh may play a role later in lung morphogenesis, immunostaining for Shh was performed in mouse lung from embryonic day (E) 10.5 to postnatal day (PD) 24. Shh was detected in the distal epithelium of the developing mouse lung from E10.5 to E16.5. From E16.5 until PD15, Shh was present in epithelial cells in both the peripheral and conducting airways. Although all cells of the developing epithelium uniformly expressed Shh at E10.5, Shh expression was restricted to subsets of epithelial cells by E16.5. Between E16.5 and PD15, non-uniform Shh staining of epithelial cells was observed in the conducting airways in a pattern consistent with the distribution of non-ciliated bronchiolar cells (i.e., Clara cells) and the Clara cell marker CCSP. Shh did not co-localize with hepatocyte nuclear factor/forkhead homologue-4 (HFH-4), β-tubulin, or with the presence of cilia. These results support the concept that Shh plays a distinct regulatory role in the lung later in morphogenesis, when it may influence formation or cytodifferentiation of the conducting airways.

The lung-specific CC10 gene is regulated by transcription factors from the AP-1, octamer, and hepatocyte nuclear factor 3 families

1993 ◽  
Vol 13 (7) ◽  
pp. 3860-3871
Author(s):  
P L Sawaya ◽  
B R Stripp ◽  
J A Whitsett ◽  
D S Luse
Keyword(s):  
Transcription Factors ◽  
Rat Liver ◽  
Transcription Initiation ◽  
Clara Cell ◽  
Clara Cells ◽  
Mobility Shift ◽  
Specific Expression ◽  
Fetal Sheep ◽  
Region I

We have shown that a large fragment (-2339 to +57) from the rat CC10 gene directed lung-specific expression of a reporter construct in transgenic animals. Upon transfection, a smaller fragment (-165 to +57) supported reporter gene expression exclusively in the Clara cell-like NCI-H441 cell line, suggesting that a Clara cell-specific transcriptional element resided on this fragment (B. R. Stripp, P. L. Sawaya, D. S. Luse, K. A. Wikenheiser, S. E. Wert, J. A. Huffman, D. L. Lattier, G. Singh, S. L. Katyal, and J. A. Whitsett, J. Biol. Chem. 267:14703-14712, 1992). The interactions of nuclear proteins with a particular segment of the CC10 promoter which extends from 79 to 128 bp upstream of the CC10 transcription initiation site (CC10 region I) have now been studied. This sequence can stimulate both in vitro transcription in H441 nuclear extract and transient expression of reporter constructs in H441 cells. Electrophoretic mobility shift assays using extracts from H441, HeLa, rat liver, and fetal sheep lung cells were used to demonstrate that members of the AP-1, octamer, and HNF-3 families bind to CC10 region I. Transcription factors from H441 cells which are capable of binding to CC10 region I are either absent in HeLa, rat liver, and fetal sheep lung extracts or enriched in H441 extracts relative to extracts from non-Clara cells.

Sign in / Sign up

Export Citation Format

Share Document