[Effects of maternal protein-calorie malnutrition on the concentration of protein A messenger RNA in surfactant of fetal rat lungs].
The pulmonary surfactant is a lipoproteic complex that serves to lower surface tension at the air-liquid interface in the pulmonary alveoli. Approximately 2 to 4% of the pulmonary surfactant is constituted by the protein A (SP-A). The objective of the study was to determine the effects that maternal protein calorie malnutrition has on the fetal pulmonary growth and the production of SP-A messenger RNA in fetal rats.


METHODS
Pregnant Sprague Dawley rats were divided into two groups, which received a diet with either 8% or 21% of proteins from gestational day 1 until the day 20. In this last day 11 fetuses were extracted by caesarean section and their lungs were removed to quantify the mRNA of the SP-A. First the mRNA was boosted using the technique of reverse transcriptase and polimerase chain reaction (RT-PCR) and then its concentration was determined by means of fluorodensitometry.


RESULTS
There was a reduction in body weight and in wet lung weights of malnourished fetuses in comparison with the normal fetuses (5.03 +/- 0.20 g vs. 4.32 +/- 0.32 g, p < 0.05 and 79.0 +/- 3.8 mg vs. 146.0 +/- 3.4 mg, p < 0.05, respectively). The densitometric analysis of the SP-A mRNA concentration demonstrated a reduction of 32% in the malnourished fetuses (0.52 +/- 0.11 vs. 0.77 +/- 0.07, p < 0.05) compared with the normal fetuses.


CONCLUSIONS
The maternal protein calorie malnutrition affected the pulmonary development and the synthesis of the SP-A mRNA. These data suggest that a defect occurrs at pre-transcriptional level that results in a diminution of the concentration of mRNA of SP-A in the neumocytes type II.
Adames
A E
AE
Sección of Immunología, Departmento de Microbiología, Escuela de Medicina, Universidad de Panamä.
Requena
C R
CR
Pascale
J M
JM
Adames
M
M
D000818:Animals; D005260:Female; D008168:Lung / Q000196:embryology*; D011247:Pregnancy; D011248:Pregnancy Complications; D011502:Protein-Energy Malnutrition; D037662:Pulmonary Surfactant-Associated Protein A / Q000235:genetics*; D011663:Pulmonary Surfactants / Q000737:chemistry*; D012333:RNA, Messenger / Q000032:analysis*; D051381:Rats; D017207:Rats, Sprague-Dawley
D037662:Pulmonary Surfactant-Associated Protein A; D011663:Pulmonary Surfactants; D012333:RNA, Messenger