Tomato juice protects the lungs of the offspring of female rats exposed to nicotine during gestation and lactation.

Maternal nicotine exposure during gestation and lactation adversely affects lung development in the offspring. It has been suggested that the "program" that control long-term maintenance of the structural integrity of the lung may be compromised. The aim of the study was to study the long-term effect of maternal nicotine exposure on the structural integrity of the lungs of the offspring, and secondly to determine whether supplementing the mother's diet with tomato juice, as a rich source of antioxidants such as lycopene, will prevent the effects of nicotine on the lungs of the offspring. Wistar rats were used in the study. After mating the rats were randomly divided into three groups. One group received nicotine (1 mg/kg body weight/day); a second group received tomato juice; and a third group received nicotine and tomato juice. The controls receive saline. Morphological and morphometric techniques were used to evaluate changes in the lung structure of the offspring at postnatal days 21, 42, 63, and 84. Neither nicotine nor tomato juice had any effect on the growth of the offspring. Although maternal nicotine exposure during gestation and lactation had no effect on the lung parenchyma of the offspring up to weaning, deterioration, and other structural changes started to appear around postnatal day 42, that is, 3 weeks after weaning and thus the onset of nicotine withdrawal. Microscopic emphysema was apparent at postnatal day 42, the increase in male and female lung volume from postnatal day 63 and thickening of the alveolar walls at postnatal day 84. All these nicotine-induced structural changes were prevented by supplementing the mother's diet with tomato juice.

Effect of maternal nicotine exposure on neonatal rat lung development: protective effect of maternal ascorbic acid supplementation.

In previous studies it was shown that maternal nicotine exposure during pregnancy and lactation interfered with fetal and neonatal lung growth and development. It was suggested that the adverse effects of maternal nicotine exposure on the lungs of the offspring may be due to inadequate protection of these lungs against oxidants. Wistar rats were used in this study. After mating the rats were randomly assigned into 4 groups, namely a control group, a group receiving only nicotine, a group exposed to only vitamin C, and a group exposed to both nicotine and vitamin C. The aim of this study was, firstly, to determine the effect of maternal nicotine exposure (1 mg/kg body weight/day, subcutaneously) during gestation and lactation on the lungs of the offspring; secondly, to test whether the subcutaneous administration of vitamin C (0.5 mg/kg body weight/day) influences lung development; and, lastly, to determine whether subcutaneous administration of vitamin C will prevent the adverse effects of maternal nicotine exposure on lung development in the offspring. Morphologic and morphometric techniques were used to determine the effect of nicotine and vitamin C on lung development in the offspring on postnatal days 14, 21, and 42. The results showed that maternal exposure to nicotine only or vitamin C only resulted in a gradual deterioration of the parenchyma of the lungs of the offspring. These changes, which resembled microscopic emphysema, only became evident after the lungs of the offspring reached maturation. Those animals that were exposed to both nicotine and vitamin C via the placenta and mother's milk were less severely affected. It is also not advisable to use subcutaneous administration of vitamin C during gestation and lactation to prevent smoke- and nicotine-related effects on the developing lung, and other strategies should be investigated.

Influence of maternal nicotine exposure during gestation and lactation on lactate dehydrogenase isoenzyme profile and transcript levels in developing neonatal rat lung.

In this study we investigated the effect of (a) aging on rat lung lactate dehydrogenase (LDH) mRNA expression and isoenzyme profile and, (b) the effect of maternal nicotine exposure during gestation and lactation on LDH isoenzyme profile and mRNA expression in the lungs of the offspring. Pregnant rats were injected subcutaneously (1mg nicotine/kg body weight/day) from day 1 after mating. Lung tissue to determine LDH isoenzyme profile and mRNA expression was obtained from the offspring. LDH mRNA expression and isoenzyme profile was determined on postnatal days 1, 7, 14, 21 and 49. Generally the %Densities of all the isoenzymes decreased between postnatal days 1 and 49. Between postnatal days 7 and 14, a period associated with rapid alveolar formation, all isoenzymes except LDH-1, decreased (P<0.01). During this period all the isoforms in nicotine-exposed lung increased (P<0.05). In both control and nicotine-exposed lung LDH-1 is the dominant isoenzyme. The LDH-M and LDH-H isoenzyme levels are higher (P<0.001) in the lungs of the nicotine exposed rats. Maternal nicotine exposure during gestation and lactation changed the metabolic status of the nicotine-exposed lungs to become more glycolytic compared to that of the control lung. These changes in LDH isoenzyme profiles and mRNA expression are irreversible.

Chronic maternal nicotine exposure during gestation and lactation and the development of the lung parenchyma in the offspring. Response to nicotine withdrawal.

THE AIM OF THIS STUDY WAS TO INVESTIGATE THE EFFECT OF MATERNAL NICOTINE EXPOSURE DURING GESTATION AND LACTATION ON: (1) the development of the gas exchange area of the lungs of the offspring; and (2) to determine whether these effects are reversible. Pregnant rats received daily nicotine (subcutaneously 1mgkg(-1) body weight) during gestation and lactation. Nicotine administration started 1 day after mating and lasted until weaning on postnatal day 21. The offspring were exposed to nicotine via the placenta and mother's milk only. The lung tissue of the neonates was collected on postnatal days 14, 21, 35 and 42 and prepared for morphometry. The results obtained show that maternal nicotine exposure resulted in bigger alveolar volumes and suppressed alveolarisation in the lungs of the offspring. Flattening of the alveoli occurred as the animals aged and as a consequence the internal surface area available for gas exchange decreased; a condition that resembles panlobular emphysema. It is unlikely that these effects of maternal nicotine exposure during gestation and lactation on lung development in the offspring was due to a lower birth weight, or a reduction in the period of gestation, or a poor supply of nutrients to the offspring. The changes in the gas-exchange region of the nicotine-exposed rat pups appear to be irreversible.

Is maternal copper supplementation during alveolarization protecting the developing rat lung against the adverse effects of maternal nicotine exposure? A morphometric study.

In a previous study, it was shown that maternal nicotine exposure during gestation and lactation interfered with alveolarization and resulted in gradual deterioration of the lung parenchyma, resulting in microscopic emphysema. The aim of this study was thus to investigate the long-term effects of maternal nicotine exposure (1 mg/kg body weight/day, subcutaneous [sc] from the onset of the phase of rapid alveolarization, which occur from postnatal day 4 in rats, on (1) the development of the gas-exchange area of the lungs of the offspring and, (2) whether maternal copper supplementation (1 mg/kg body weight/day, SC) during the same period of time will prevent the effect of maternal nicotine exposure on the development of the neonatal rat lung. Nicotine administration lasted until weaning on postnatal day 21. The day of birth was designated day 0. The offspring were exposed to nicotine via the mother's milk only. The experimental animals received no nicotine or copper after postnatal day 21. The lung tissue of the neonates was collected on postnatal days 14, 21, and 42 and prepared for morphometry. The results obtained show that maternal nicotine exposure had no influence on body weight, chest circumference, crown-rump length, and lung volume, but resulted in bigger alveolar volumes and suppressed alveolarization in the lungs of the offspring. Copper supplementation during this period of lung development reduced the adverse effect of maternal nicotine exposure on neonatal lung development. Even though copper reduced the adverse effects of maternal nicotine exposure during this phase of lung development, it did not prevent the induction of microscopic emphysema.

Maternal nicotine exposure during pregnancy and lactation: I. Effect on glycolysis in the lungs of the offspring.

We investigated the effect of maternal nicotine exposure during pregnancy and lactation on carbohydrate metabolism in the neonatal lung. Female rats received nicotine (1 mg/kg body weight/day) subcutaneously from day 7 after mating. Control animals received saline. The suckling rats were killed 24 hours after the last dose of nicotine was administered to the mother on postnatal day 14. The lung tissue of 9 rat pups from 3 litters was surgically removed and the in vitro utilization of exogenous glucose (micromol/g wet lung tissue/h) was determined. Lactate production (micromol/g wet lung tissue/h) was also determined to assess glycolytic activity. Maternal nicotine exposure during pregnancy and lactation stimulated glucose turnover by 21.6% (P<.01), but suppressed glycolysis by 24.6% (P<.001) and glycogenolysis by 37.9% (P<.001). Maternal nicotine exposure during gestation and lactation had no effect on the activity of hexokinase (U/g wet lung tissue), but resulted in a lower phosphofructokinase activity (U/g wet lung tissue) in the lungs of the offspring. From the data, it appeared that the inhibition of the flux of glucose through the glycolytic pathway can be attributed to an inhibition of phosphofructokinase.

Maternal nicotine exposure during gestation and lactation of rats induce microscopic emphysema in the offspring.

The aim of this study was thus to determine whether maternal nicotine exposure during gestation and lactation will result in early emphysema in the lungs of the offspring. Female rats received nicotine subcutaneously during gestation and lactation. Nicotine administration commenced 1 day after mating and lasted until weaning on postnatal day 21. The offspring were exposed to nicotine via the placenta and mother's milk only. Lung tissue of the neonates was collected for analysis on postnatal days 14, 21, 35 and 42. The results show that maternal nicotine exposure had no effect on the total alveolar count (Na), mean alveolar volume (Valv), and airspace wall surface area per unit volume of lung tissue (AWUV) of the 14- and 21-day-old rat pups. However, the Na of the 35- and 42-day-old control animals was higher than that of the nicotine exposed animals. The Valv of the 35- and 42-day-old nicotine exposed rat pups was however larger than that of the control animals, whereas the AWUV of the 35- and 42-day-old control animals were bigger than that of the nicotine-exposed animals of the same age. The scanning electron micrographs showed a gradual flattening of the alveoli. It is therefore concluded that maternal nicotine exposure induced changes at gene level that renders the lungs of the offspring more susceptible to emphysema-like lesions.

Effects of fetal growth restriction on lung development before and after birth: a morphometric analysis.

Our aim was to determine the effects of fetal growth restriction (FGR) during late gestation on the structure of the lungs in the fetus near term and at 8 weeks after birth. The studies were performed using two groups of pregnant sheep and their offspring. In both groups, FGR was induced by umbilico-placental embolisation (UPE); for fetal studies, UPE was performed from 120 days of gestation until 140 days (term, approximately 146 days), when fetuses were killed for tissue analysis. For postnatal studies, UPE continued from 120 days until delivery at term; postnatal lambs were killed at 8 weeks after birth for tissue analysis. UPE led to a thicker pulmonary blood-air barrier at 140 days of gestation and this difference, which was due to a thickened basement membrane, was still present at 8 weeks after birth. At 8 weeks, we also observed a smaller number of alveoli per respiratory unit, thicker interalveolar septa, and a greater volume density of lung tissue in FGR lambs compared to controls. These changes would be expected to impair gas exchange and alter the mechanical properties of the lungs. Our data show that structural alterations in the lungs induced by placental insufficiency were more evident at 8 weeks of postnatal age than near term, indicating that the effects of FGR on the lung may become more serious with age and may affect respiratory health later in life.

The compromised intra-uterine environment: implications for future lung health.

1. Epidemiological studies of infants, children and adults indicate that prenatal compromises that restrict fetal growth and cause low birthweight increase the risk of respiratory deficiencies after birth. 2. It is apparent that the lung has a limited ability to recover from early developmental compromises and that altered development can permanently impair lung architecture. 3. Lung development in utero can be adversely affected by factors associated with fetal growth restriction, namely fetal hypoxaemia, reduced substrate supply and hypercortisolaemia. 4. We have conducted a series of studies of respiratory development in chronically catheterized ovine fetuses and postnatal lambs in which growth restriction was induced during late gestation by embolizing the umbilico-placental vascular bed, a technique that replicates key aspects of human placental insufficiency. 5. During late gestation, restricting the growth of the ovine fetus did not alter lung weight or lung liquid secretion or volume when each factor was related to bodyweight, but it did lead to increased lung DNA concentrations and an increased thickness of the air-blood barrier. Expression of pulmonary surfactant proteins A, B and C were not altered and, hence, it was unlikely that surfactant protein synthesis had been impaired by growth restriction. 6. When growth restriction continued to term, lambs were born with a low birthweight and remained small compared with controls for 8 weeks after birth. Low-birthweight lambs were mildy hypoxaemic and compliances of their lungs and chest wall were, respectively, decreased and increased relative to controls. Pulmonary surfactant proteins A, B and C were not deficient, indicating that decreased lung compliance most likely had a structural basis.

Increased lung expansion alters the proportions of type I and type II alveolar epithelial cells in fetal sheep.

Type I and type II alveolar epithelial cells (AECs) are derived from the same progenitor cell, but little is known about the factors that regulate their differentiation into separate phenotypes. An alteration in lung expansion alters the proportion type II AECs in the fetal lung, indicating that this may be a regulatory factor. Our aim was to quantify the changes in the proportion of type I and type II AECs caused by increased fetal lung expansion and to provide evidence for transdifferentiation of type II into type I cells. Lung tissue samples were collected from ovine fetuses exposed to increased lung expansion induced by 2, 4, or 10 days of tracheal obstruction (TO). The identities and proportions of AEC types were determined with electron microscopy. The proportion of type II cells was reduced from 28.5 +/- 2.2% in control fetuses to 9.4 +/- 2.3% at 2 days of TO and then to 1.9 +/- 0.8% at 10 days. The proportion of type I AECs was not altered at 2 days of TO (63.1 +/- 2.3%) compared with that of control cells (64.8 +/- 0.5%) but was markedly elevated (to 89.4 +/- 0.9%) at 10 days of TO. The proportion of an intermediate AEC type, which displayed characteristics of both type I and type II cells, increased from 5.7 +/- 1.3% in control fetuses to 23.8 +/- 5.1% by 2 days of TO and was similar to control values at 10 days of TO (7.7 +/- 0.9%). Our data show that increases in fetal lung expansion cause time-dependent changes in the proportion of AEC types, including a transient increase in an intermediate cell type. These data provide the first evidence to support the hypothesis that increases in fetal lung expansion induce differentiation of type II into type I AECs via an intermediate cell type.

Changes in lung structure and cellular division induced by tracheal obstruction in fetal sheep.

Increased expansion of the fetal lung, caused by obstruction of the fetal trachea, is a potent stimulus for growth and structural development of the fetal lung. Our aim was to analyze the changes in lung structure induced by fetal tracheal obstruction and to identify cell types that contribute to the growth response. Fetal sheep were exposed to 2, 4, or 10 days of tracheal obstruction (TO) and on day 128 of gestation (term "147 d"), were injected with 3H-thymidine 8 hours before tissues were collected. The right lung was fixed at 20 cm H2O and prepared for stereological and autoradiographic analysis. Alveolar wall thickness (7.8 +/- 0.3 microns vs 5.5 +/- 0.4 microns) and percent tissue space (27.9 +/- 0.9% vs 21.4 +/- 2.8%) were increased at 2 days of TO, but were not different from control at 4 and 10 days. The luminal surface area of the right lung increased gradually from 2.4 +/- 0.2 m2/kg in control fetuses to 3.6 +/- 0.4 m2/kg following 10 days of TO and this increase was accompanied by an increase in alveolar number (control: 808 x 10(6) +/- 81.9 x 10(6) vs 10d obstruct: 1254 x 10(6) +/- 63 x 10(6). Alveolar diameter increased at 2 days of TO (51.8 +/- 1.4 microns vs 43.8 +/- 1.9 microns), but was not increased further at 4 or 10 days. The percentage of dividing cells was increased at 2 days of TO (12.64 +/- 3.39% vs 1.73 +/- 0.31%), remained elevated at 4 days (5.01 +/- 0.27%), but had returned to control by day 10. The increase at 2 days was due to division of type II epithelial cells, fibroblasts, and endothelial cells. We conclude that increased expansion of the fetal lung induces time-dependent changes in lung structure and cell division rates; these include a transient increase in alveolar wall thickness, a rapid increase in alveolar number, and a gradual increase in luminal surface area. The latter is probably caused by an increase in alveolar number rather than an increase in the alveolar size.

Effects of intra-uterine growth restriction on the control of breathing and lung development after birth.

1. Low birthweight is now recognized as an important risk factor for early postnatal respiratory illness and it is becoming evident that low birthweight can increase the risk for airway dysfunction in children and adults. Our studies have been aimed at determining how low birthweight, resulting from intra-uterine growth restriction (IUGR), affects the control of breathing and the structural and functional development of the lung. 2. We have measured ventilatory responsiveness to progressive hypoxia and progressive hypercapnia during the first weeks after birth in postnatal lambs in which IUGR was induced by chronic placental insufficiency. It was found that the postnatal increase in ventilatory sensitivity to hypoxia observed in control lambs was diminished in low birthweight lambs; in contrast, the sensitivity to hypercapnia was not affected. In other studies, we found that IUGR caused by maternal anaemia led to elevated CO2 levels during sleep and wakefulness. 3. Our findings suggest that the prenatal development of the brain-stem or respiratory chemoreceptors may be affected by intra-uterine factors associated with IUGR, such as foetal hypoxaemia or hypoglycaemia. It is also possible that the structure of respiratory muscles and, hence, their ability to maintain a high level of ventilation may be affected by IUGR. 4. Recently, we studied the influence of IUGR on foetal lung development, in particular its effects on foetal lung liquid, a major determinant of lung growth, as well as alveolar structure and pulmonary surfactant. Lung liquid secretion and volume, in relation to bodyweight, were unaffected; however, there was evidence of structural and functional immaturity in the lungs. In foetuses exposed to IUGR, the air-blood barrier was thicker and, after birth, the diffusing capacity of the lungs for carbon monoxide was lower. In contrast, surfactant protein gene expression was enhanced, particularly in foetuses with high levels of circulating cortisol. 5. Further studies are needed to characterize the effects of specific types of prenatal compromise on postnatal control of ventilation and lung function, to determine mechanisms underlying these effects and to determine the capacity for postnatal recovery.

Maternal copper supplementation protects the neonatal rat lung against the adverse effects of maternal nicotine exposure.

Maternal nicotine exposure interferes with the extracellular formation of the connective tissue framework of the neonatal lung, a process that is dependent on copper-dependent lysyl oxidase. It has been shown that, during the phase of lung development associated with alveolarization, maternal nicotine exposure resulted in a reduction in the copper content and thus conceivably in the activity of lysyl oxidase of the neonatal lung. Therefore the aims of this study were (a) to determine the effects of maternal nicotine exposure during gestation and lactation on neonatal lung development, and (b) to establish whether maternal copper supplementation during gestation and lactation prevented the effect of maternal nicotine exposure on neonatal lung development. Pregnant rats were randomly divided into four groups: the control group received saline; the second group received 1 mg nicotine (kg bodyweight)(-1) day(-1) subcutaneously; the third group received 1 mg copper (kg bodyweight)(-1) day(-1); and the fourth group received both nicotine and copper in the same quantities as the previous two groups. Lung tissue of 14- and 42-day-old rat pups were processed for light microscopy. Maternal nicotine exposure during gestation and lactation resulted in (a) decreased alveolar number, (b) reduced internal surface area and (c) increased alveolar volume. Copper supplementation during gestation and lactation prevented the adverse effects of maternal nicotine exposure during gestation and lactation on the development of the alveolar region of the rat lung.

Maternal nicotine exposure during gestation and lactation interferes with alveolar development in the neonatal lung.

The aim of this study was to investigate the effect of maternal nicotine exposure during pregnancy and lactation on the development of the lungs of the offspring as a gas-exchanger. Pregnant rats received nicotine (1 mg/kg body mass day(-1)) subcutaneously during gestation and lactation. Nicotine administration started one day after mating and lasted until weaning on post natal Day 21. The offspring were exposed to nicotine only via the placenta and the milk of the mother. The lung tissue of the neonates was collected on post natal Days 14, 21, 35 and 42 and prepared for morphometry. The results obtained show that maternal nicotine exposure suppressed alveolarisation in the lungs of the offspring, which resulted in a reduced internal surface area available for gas exchange. The radial alveolar count as well as the number of capillaries in the septa were also significantly lower than in the control animals. It is concluded that maternal nicotine exposure had an adverse effect on the development of the gas exchange region of the lungs of the offspring that persisted at least up to Day 42 after birth.

Influence of maternal nicotine exposure on neonatal rat lung structure: protective effect of ascorbic acid.

The aims of this study were (1) to determine and quantify the adverse effects of maternal nicotine exposure during pregnancy and lactation on neonatal rat lung development, and (2) to establish whether ascorbic acid will protect the neonatal rat lung against the adverse effects of maternal nicotine exposure. Pregnant rats received nicotine (1 mg/kg body mass/day) subcutaneously during gestation and lactation. A second group received nicotine and ascorbic acid (1 mg/kg body mass/day). The control animals received saline subcutaneously. The results illustrate that maternal nicotine exposure results in (a) a decreased (P < 0.001) radial alveolar count (RAC), (b) an increase (P < 0.001) in destructive index (DI), (c) an increased (P < 0.001) linear intercept (Lm), (d) an increased (P < 0.001) abnormal alveolar attachment index (AAA) (e) and an increase in septal cellularity. Ascorbic acid does not protect fetal lung development against the adverse effects of maternal nicotine exposure. However, after birth ascorbic acid prevents further deterioration of the DI, AAA and Lm, whereas the RAC and thus the number of alveoli was even higher than in control neonatal rat lung. No further increase in cellularity occurred. The reason for this response to ascorbic acid supplementation is under investigation.

Maternal nicotine exposure: response of type II pneumocytes of neonatal rat pups.

The influence of maternal nicotine exposure during pregnancy and lactation on the Type II cells of lung tissue of one day old neonatal rat pups was investigated. The results clearly show that maternal nicotine exposure resulted in an increase in the type II cell count in the lungs of the offspring. In addition the lamellar body content of the type II cells of the nicotine exposed rat pups were significantly (P < 0.01) higher than that of the control animals. The type II cell mitochondria of lung tissue of nicotine exposed rat pups were swollen and no microvilli occurred on the alveolar surface. This clearly illustrates that nicotine interfered with type II cell integrity of tlte neonatal lung and may subsequently interfere with the normal development of the alveolar region of the lung.

The influence of maternal nicotine exposure on the interalveolar septal status of neonatal rat lung.

The aim of this study was to determine the effect of maternal nicotine exposure (1 mg nicotine/kg body mass/day, subcutaneously) on the status of the alveolar septa of the 1 to 21 day old offspring. The data obtained showed swelling of type II and interstitial cell mitochondria. The type I:type II cell ratio decreased as a result of type II cell proliferation. The number of capillaries per unit length of septum was also significantly lower than that of control lung. Ruptured blood-air barriers also occur in the nicotine exposed lungs of rats of all age groups. The results show that maternal nicotine exposure interfered with the morphometric and morphologic characteristics of the septa of lung tissue of the offspring.

The influence of maternal nicotine exposure on neonatal lung alveolar epithelial status: an electron microscope study.

The aim of the present study was to investigate the effect of maternal nicotine exposure (1 mg nicotine/kg body mass/day) on neonatal lung alveolar epithelial cells. Rats (Wistar descendants) were used. The data illustrate that maternal nicotine exposure during pregnancy and lactation resulted in alveolar fenestrations, blebbing and rupturing of the blood-air barrier. The type I pneumocyte appears to be more sensitive to the effect of nicotine than the type II pneumocytes.

Carbohydrate metabolism of lung tissue of suckling and adult rats.

The carbohydrate metabolism of lung tissue of suckling (1-3 weeks) and adult (40-42 weeks) rats were investigated and compared. The results showed that the apparent km for in vitro glucose utilization was 3.13 nM for adult lung and the V max 136.99 mumol/g/h. This could not be determined for neonatal animals. The rate of glucose entry into the glycolytic pathway of adult lung was faster than in the lung of neonatal rats. However, glycogen utilization by neonatal lung was faster than by adult lung. The in vitro oxygen consumption of the lung tissue slices of both age groups were the same. It is proposed that the slower rate of glucose entry into glycolysis in lung tissue of suckling rats is due to a different hexokinase isoenzyme profile. It is also concluded that glycogen-glucose plays a major role in lung development.