Compensatory lung growth: protein, DNA and RNA lung contents in undernourished trilobectomized rats

Aiming at assessing compensatory lung growth after trilobectomy in rats, 3 groups of animals (control, thoracotomy and trilobectomy) were studied over 3 time intervals (7, 30 and 180 days post-operation). Protein, DNA and RNA contents in each lung were evaluated. The study of the left lung protein content reveals that compensatory growth ceased by day 30, whereas it continued to occur in the cranial lobe as long as 180 days post-operation. The lung DNA content in trilobectomized animals remained smaller than in the animals of the other groups demonstrating that compensatory growth was not brought about by hyperplasia. The lung RNA content in trilobectomized animals increased similarly to the lung protein content, demonstrating that the cells of the lung tissue must have had an increase in volume as no significant increase in their number occurred, as shown by the analysis of the lung DNA content. Therefore, it may be concluded that, in our experiment with adult animals, compensatory lung growth after trilobectomy in rats occurred due to an increase in the lung protein content and RNA content, suggesting a cellular volume increase (hypertrophy) and a probable increase in the intralveolar septs rather than an important cell multiplication

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Long-term consequences of compensatory lung growth

Journal of Applied Physiology ◽

10.1152/jappl.1989.66.6.2891 ◽

1989 ◽

Vol 66 (6) ◽

pp. 2891-2894 ◽

Cited By ~ 6

Author(s):

W. M. Thurlbeck ◽

C. Langston

Keyword(s):

Lung Volume ◽

Tissue Loss ◽

Lung Growth ◽

Lung Weight ◽

Compensatory Lung Growth ◽

Dna And Rna ◽

Volume Weight ◽

New Zealand White Rabbits ◽

The Right

Left pneumonectomy or left nephrectomy was performed on 10-wk-old littermate male New Zealand White rabbits, and they were killed at 30 wk of age. Thirty-week-old male littermates served as controls. Nephrectomy was done to produce major tissue loss and trauma and to assess blood somatomedin C. At the end of the experiment, the right lungs of the pneumonectomy animals had a greater lung volume, weight, gas-exchanging surface area, and alveolar number than the nephrectomy animals and the controls, and their air spaces were the same size. When compared with both lungs of the nephrectomy group and the controls, lung weight was the same; lung volume, alveolar number, and protein were not significantly less in the pneumonectomy group, but gas-exchanging area (compared with controls only), DNA, and RNA were. After left nephrectomy, the right kidney increased in weight; nephrectomy had no effect on lung size or structure. We conclude that pneumonectomy at age 10 wk in male rabbits results in significant compensatory lung growth, including alveolar multiplication, and this persists to age 30 wk. Compensatory lung growth, however, was incomplete; that is, it did not reconstitute (equal) in all respects that of both lungs of the nephrectomy animals or the controls.

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Rapidity of compensatory lung growth following pneumonectomy in adult rats

Journal of Applied Physiology ◽

10.1152/jappl.1979.46.2.326 ◽

1979 ◽

Vol 46 (2) ◽

pp. 326-333 ◽

Cited By ~ 45

Author(s):

D. E. Rannels ◽

D. M. White ◽

C. A. Watkins

Keyword(s):

Body Weight ◽

Cell Size ◽

Left Lung ◽

Weight Ratio ◽

Lung Growth ◽

Body Weight Ratio ◽

Adult Rats ◽

Lung Weight ◽

Wet Weight ◽

The Right

The rapidity with which lung growth was initiated following pneumonectomy was investigated using rats (330 g) in which lung weight-to-body weight ratio and lung cell size had stabilized. Following removal of the left lung, right lung weight increased from 823 to 1.161 mg within 7 days. Right lung weight in sham-operated animals did not change significantly. At day 7, right lung weight-to-body weight ratio in pneumonectomized rats was equal to that of both lungs in sham-operated animals; these values remained equal through day 14. Growth of individual lobes of the right lung was generally in proportion to their initial weights. Dry-to-wet weight ratio in either lung of sham-operated or pneumonectomized animals was unchanged, as compared to unoperated controls. Total right lung RNA and protein increased significantly by day 2 and reached levels equal to those in both lungs of sham-operated animals by day 7. Synthesis of lung proteins, estimated during 120 min of perfusion in situ, was elevated 25% on day 3. Incorporation of [3H]thymidine into DNA increased somewhat on day 2 and was elevated fourfold on day 3, corresponding with the initial accumulation of total DNA within the lung. These observations suggested that increased cell size may accompany early compensatory growth following pneumonectomy, but that the major portion of the response involved cellular hyperplasia.

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Expression of α-smooth muscle actin in the periodontal ligament during post-emergent tooth eruption

Journal of International Medical Research ◽

10.1177/0300060518769545 ◽

2018 ◽

Vol 46 (6) ◽

pp. 2423-2435

Author(s):

Domna Dorotheou ◽

Marie-Luce Bochaton-Piallat ◽

Catherine Giannopoulou ◽

Stavros Kiliaridis

Keyword(s):

Smooth Muscle ◽

Periodontal Ligament ◽

Smooth Muscle Actin ◽

Root Apex ◽

Tooth Eruption ◽

Muscle Actin ◽

Adult Rats ◽

Time Points ◽

Male Wistar Rats ◽

The Right

Objective This study was performed to explore the expression of α-smooth muscle actin (α-SMA) in the periodontal ligament (PDL) of young and adult rats during post-emergent tooth eruption in opposed and unopposed teeth at two time points: 3 and 15 days after antagonist loss. Methods Four-week-old (n = 20) and 22-week-old (n = 20) male Wistar rats were used. The right maxillary molar crowns were cut down. PDL samples were isolated from the first mandibular molars at two time points: 3 and 15 days after cut-down of the right maxillary molars. Quantitative reverse-transcription polymerase chain reaction and immunohistochemical staining were performed to detect differences in α-SMA expression in the PDL tissues of unopposed versus opposed molars. Results α-SMA was upregulated in the PDL of the unopposed molars in the 3-day group of young rats. The region around the root apex of the unopposed molars in this group exhibited strong immunostaining for α-SMA. The expression level and immunoreactivity of α-SMA did not differ in both time points in young controls and among all the adult groups. Conclusion α-SMA-positive myofibroblasts are implicated in post-emergent tooth eruption of unopposed molars of young animals.

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Effects of prior adrenalectomy on postpneumonectomy lung growth in the rat

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1985.248.1.e70 ◽

1985 ◽

Vol 248 (1) ◽

pp. E70-E74 ◽

Cited By ~ 1

Author(s):

R. A. Bennett ◽

P. C. Colony ◽

J. L. Addison ◽

D. E. Rannels

Keyword(s):

Dry Mass ◽

Hydrocortisone Acetate ◽

Lung Growth ◽

Sprague Dawley ◽

Treatment Groups ◽

Compensatory Lung Growth ◽

Sprague Dawley Rats ◽

Total Dna ◽

Glucocorticoid Replacement Therapy ◽

The Right

The effects of adrenalectomy, with and without subsequent glucocorticoid replacement therapy, on postpneumonectomy compensatory lung growth in the rat were investigated. Male Sprague-Dawley rats (200-230 g) were subjected to no operation (UNOP), left pneumonectomy (PNX), or PNX preceded by bilateral adrenalectomy 5 days earlier (ADX/PNX). At 14 days post-PNX, when compensatory lung growth is normally complete in 200-g rats, right lung (RL) dry weights of PNX (263 +/- 6 mg, n = 26) and ADX/PNX (334 +/- 13 mg, n = 25) rats were increased 58 and 101%, respectively, relative to UNOP controls (166 +/- 5 mg, n = 10). Increases in total DNA, RNA, and protein in the right lungs of PNX and ADX/PNX rats occurred in proportion to RL dry mass. The increase in all parameters examined in PNX and ADX/PNX rats at 7 days post-PNX was half that at 14 days, indicating linear lung growth in both treatment groups. The stimulatory effect of ADX on lung growth was blocked by hydrocortisone acetate (HCA), administered intraperitoneally in daily doses of 5 mg/kg, beginning on the day of PNX. The RL dry weights of HCA-treated ADX/PNX rats (241 +/- 7 mg, n = 10) did not differ significantly from the corresponding value in PNX rats (270 +/- 14 mg, n = 7). The lower RL weights in the HCA-treated rats resulted from an inhibition of cell division, as evidenced by the total RL DNA content, which was similar to that in PNX animals.(ABSTRACT TRUNCATED AT 250 WORDS)

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Control of compensatory lung growth by adrenal hormones

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1987.253.4.e343 ◽

1987 ◽

Vol 253 (4) ◽

pp. E343-E348 ◽

Cited By ~ 3

Author(s):

D. E. Rannels ◽

H. W. Karl ◽

R. A. Bennett

Keyword(s):

Dry Mass ◽

Lung Mass ◽

Lung Growth ◽

Unoperated Control ◽

Adrenal Hormones ◽

Compensatory Lung Growth ◽

The Right ◽

Rna And Dna ◽

Left Pneumonectomy

The effects of adrenalectomy and/or in vivo treatment with hydrocortisone acetate (HCA;5 mg X kg-1 X day-1) on lung growth were investigated in control and pneumonectomized rats of 250 g body wt. Left pneumonectomy (day 0) initiated rapid hyperplastic growth of the right lung, which was unaffected by HCA. Similarly, HCA had no effect on lung growth in unoperated control animals. Two weeks after pneumonectomy, right lung dry mass, protein, RNA, and DNA were equal to that in both lungs of unoperated rats. Adrenalectomy 5 days before (day -5) left pneumonectomy increased the rate and extent of right lung growth, but did not change its hyperplastic character. Continuous HCA treatment (days -5 to 14) prevented the adrenalectomy-mediated increase in postpneumonectomy lung growth. "Early" HCA dosing (days -5 to 6) of adrenalectomized-pneumonectomized animals suppressed lung growth to the pneumonectomy level, but from days 7 to 14 growth accelerated to the adrenalectomized-pneumonectomized rate. Conversely, "late" HCA, initiated when adrenalectomized-pneumonectomized animals had restored normal total lung mass (days 6 to 14), quickly reduced right lung growth to rates typical of unoperated controls. The latter effects were not observed unless continuous steroid treatment was provided throughout this interval. The data support a role for glucocorticosteroids in modulation of the accelerated compensatory lung growth initiated by partial resection of the tissue.

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Lung volumes after an increase in lung distension in pneumonectomized ferrets

Journal of Applied Physiology ◽

10.1152/jappl.1989.67.4.1418 ◽

1989 ◽

Vol 67 (4) ◽

pp. 1418-1421 ◽

Cited By ~ 14

Author(s):

J. T. McBride

Keyword(s):

Lung Resection ◽

Transpulmonary Pressure ◽

Tissue Growth ◽

Lung Growth ◽

Lung Volumes ◽

Compensatory Lung Growth ◽

Rubber Balloon ◽

Residual Capacity ◽

The Right

To investigate the role of lung distension in compensatory lung growth, the right lung of each of 21 adult male ferrets was replaced with a silicone rubber balloon filled with mineral oil. Three to thirteen weeks after surgery, the oil was removed through a subcutaneous port. Lung volumes were measured serially until 3–6 wk after balloon deflation. With pneumonectomy the total lung capacity (TLC) decreased to less than 50% of the preoperative value and remained essentially unchanged while the balloon was inflated. At balloon deflation, TLC and vital capacity did not change immediately, whereas functional residual capacity increased by 44%, indicating a change of 2–3 cmH2O in end-expiratory transpulmonary pressure. TLC increased by 10% within 3 days and continued to increase over the subsequent 3–5 wk by a total of 25% over TLC at balloon deflation. There was little difference in this response between animals whose balloons were deflated 3 wk after surgery and those in which deflation was delayed up to 13 wk. After pneumonectomy in the adult ferret, the remaining lung increases in volume in response to an increase in lung distension even weeks or months after surgery. The extent to which this volume increase involves lung tissue growth or depends on previous lung resection is at present unknown. This model may be useful for studies of the mechanisms by which lung distension influences lung volume and compensatory lung growth.

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Effect of lung collapse on compensatory lung growth

Journal of Applied Physiology ◽

10.1152/jappl.1977.43.1.27 ◽

1977 ◽

Vol 43 (1) ◽

pp. 27-31 ◽

Cited By ~ 10

Author(s):

L. S. Inselman ◽

R. B. Mellins ◽

J. A. Brasel

Keyword(s):

Left Lung ◽

Lung Growth ◽

Lung Collapse ◽

Halothane Anesthesia ◽

Adult Rat ◽

Compensatory Lung Growth ◽

Contralateral Lung ◽

Old Adult ◽

Old Rats ◽

Long Evans

The effect of unilateral lung collapse on compensatory lung growth was studied in 3-wk-old (young) and 10-wk-old (adult) male Long-Evans rats. Under light halothane anesthesia, left lung collapse was produced by injection of dental plastic through a thracheostomy cannula. The rats were killed either 5 days or 4 wk later. At 5 days postcollapse, the 3-wk-old rats had an increase in DNA over sham controls (21%) (P less than 0.05), with no significant change in the protein/DNA ratio. At 4 wk postcollapse, increases in DNA over shamoperated controls were observed in both the 3-wk-old (58%) and the 10-wk-old (28%) rats, whereas the protein/DNA ratio at both ages was significantly less than that of sham controls (P less than 0.05). Thus, unilateral lung collapse stimulates growth of the contralateral lung by cellular hyperplasia, not hypertrophy, both in the young and adult rat. The hyperplasia begins within 5 days after collapse and is greater by 4 wk. The extent of hyperplasia is greater in the young than in the adult rat.

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Localization and stretch-dependence of lung elastase activity in development and compensatory growth

Journal of Applied Physiology ◽

10.1152/japplphysiol.00954.2014 ◽

2015 ◽

Vol 118 (7) ◽

pp. 921-931 ◽

Cited By ~ 11

Author(s):

Sarah Marie Young ◽

Sheng Liu ◽

Rashika Joshi ◽

Matthew R. Batie ◽

Matthew Kofron ◽

...

Keyword(s):

Ex Vivo ◽

Left Lung ◽

Mouse Lung ◽

Matrix Remodeling ◽

Lung Growth ◽

Elastase Activity ◽

Compensatory Lung Growth ◽

The Matrix ◽

Applied Forces ◽

Lung Matrix

Synthesis and remodeling of the lung matrix is necessary for primary and compensatory lung growth. Because cyclic negative force is applied to developing lung tissue during the respiratory cycle, we hypothesized that stretch is a critical regulator of lung matrix remodeling. By using quantitative image analysis of whole-lung and whole-lobe elastin in situ zymography images, we demonstrated that elastase activity increased twofold during the alveolar stage of postnatal lung morphogenesis in the mouse. Remodeling was restricted to alveolar walls and ducts and was nearly absent in dense elastin band structures. In the mouse pneumonectomy model of compensatory lung growth, elastase activity increased threefold, peaking at 14 days postpneumonectomy and was higher in the accessory lobe compared with other lobes. Remodeling during normal development and during compensatory lung growth was different with increased major airway and pulmonary arterial remodeling during development but not regeneration, and with homogenous remodeling throughout the parenchyma during development, but increased remodeling only in subpleural regions during compensatory lung growth. Left lung wax plombage prevented increased lung elastin during compensatory lung growth. To test whether the adult lung retains an innate capacity to remodel elastin, we developed a confocal microscope-compatible stretching device. In ex vivo adult mouse lung sections, lung elastase activity increased exponentially with strain and in peripheral regions of lung more than in central regions. Our study demonstrates that lung elastase activity is stretch-dependent and supports a model in which externally applied forces influence the composition, structure, and function of the matrix during periods of alveolar septation.

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