Effect of epidermal growth factor and dexamethasone on fetal rat lung development.

Department of Pediatrics, Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong 515041, China.
Chinese medical journal (Impact Factor: 1.02). 09/2009; 122(17):2013-6.
Source: PubMed

ABSTRACT Epidermal growth factor (EGF), a mitogenic polypeptide that binds to cell surface receptors, is an important regulator of cell differentiation and fetal lung surfactant synthesis. We investigated the preventive and therapeutic effects of EGF in respiratory distress syndrome, by administering EGF and dexamethasone (Dex) to mother rat before delivery.
Six female Sprague-Dawley (SD) rats were assigned to three groups (2 rats each); EGF or Dex was given to pregnant rats (EGF group and Dex group, respectively) from gestational day 16 to day 18 by intraperitoneal injection, while the group with normal saline injection was used as negative controls. Fetal rats were taken out of womb by hysterotomy on day 19 of pregnancy, then 24 fetal rats were randomly chosen from each group. Their body weights were measured, and pulmonary surfactant protein-A and -B (SP-A and SP-B) antigens were determined by immunohistochemical staining in each group. The histologic structure was examined under a light microscope, a light microscopic image system or an electron microscope.
The expressions of SP-A and SP-B could be detected in each group. A significant difference was observed for SP-A and SP-B in the EGF and Dex groups compared with the control group (P < 0.01). Image analysis showed that the relative values of air space area and interalveolar septa area in the EGF and Dex groups were significantly greater than those in the control group (P < 0.01), while no significant difference was found between the two groups (P > 0.05). The ultrastructural features of fetal lungs showed that the number of alveolar type II cells containing lamellar bodies in the EGF and Dex groups was apparently increased compared with that in the control group. The mean body weight of fetus from the Dex group was smaller than that from the control group ((1.3192 +/- 0.0533) g, (1.3863 +/- 0.0373) g), but there was no significant difference between the EGF group and the control group ((1.3986 +/- 0.0730) g, (1.3863 +/- 0.0373) g).
Maternal treatment with EGF and Dex on days 16 - 18 of gestation could promote morphogenesis and increase the surfactant levels in premature fetal lung. However, maternal treatment with Dex, not EGF, decreased the body weight.

  • American Journal of Respiratory and Critical Care Medicine 05/2000; 161(4 Pt 1):1074-5. · 11.99 Impact Factor
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    ABSTRACT: Randomised clinical trials show that two injections of corticosteroid into the mother before preterm delivery reduce respiratory distress syndrome, neonatal mortality, and intraventricular haemorrhage. However, repeated courses of antenatal steroid are not backed by such evidence of safety and efficacy. Animal studies have shown that maternal corticosteroid delays myelination and reduces the growth of all fetal brain areas particularly the hippocampus. Corticosteroids may reduce or enhance hypoxic-ischaemic injury to the developing brain depending on timing and dosage. Clinical trials of maternally administered corticosteroid show no evidence of increased disability on follow up but numbers are small. Postnatal trials of dexamethasone when brain maturity is still preterm show a significant increase in later disability in the dexamethasone treated groups. There is evidence from randomised trials, retrospective data, experiments on pregnant mice, and the chemical make up of the preparations that betamethasone may be safer and more protective of the immature brain than dexamethasone. Single course corticosteroid treatment before preterm delivery must still be recommended as a life saving and cost effective intervention, but clinicians may wish to change from using dexamethasone to betamethasone. In view of the animal and postnatal data, clinicians should be cautious with repeated courses of antenatal corticosteroids and repetition may be unnecessary for lung maturity.
    Archives of Disease in Childhood - Fetal and Neonatal Edition 10/2000; 83(2):F154-7. · 3.86 Impact Factor


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