Short- and long-term effects of a neonatal low-protein diet in rats on the morphology of the larynx.
OBJECTIVE
The aim of this study was to investigate the short- and long-term effects of a maternal low-protein diet during lactation on offspring laryngeal morphology. Our hypothesis was that a neonatal low-protein diet during the critical period of development alters micro- and macroscopic structures of the larynx in adult rats.


METHODS
Male Wistar rats were assigned to a control (casein 17%, n=24) or low-protein (casein 8%, n=24) group according to their mother's diet during lactation. Body weight gain and growth rate were recorded throughout the experiment. The larynx was removed from offspring at days 22 and 60 of life. The anteroposterior and laterolateral lengths of the cartilages epiglottis, thyroid, and cricoid were measured by a digital caliper. The supraglottis, glottis, infraglottis, and vocal cords were stained by hematoxylin-eosin and their structures were analyzed by a Scion Image Beta 4.0.2 program.


RESULTS
Pups from mothers fed a low-protein diet showed a lower body weight gain. The laterolateral and anteroposterior lengths of the larynx were shorter in undernourished offspring at 22 d old. There were no differences in the structure of the supraglottis, glottis, and infraglottis between groups except for keratinization in pups from undernourished mothers. The microstructure of the vocal cords was changed only at 60 d old.


CONCLUSIONS
Macroscopic structures of the larynx are sensitive to short-term effects of a neonatal low-protein diet. Vocal cord development can be studied within the context of programming because their microscopic structures are sensitive to the long-term effects of a low-protein diet during lactation.
Pires-de-Mélo
Iracema Hermes
IH
Department of Nutrition and Pathology, Federal University of Pernambuco, Recife, Brazil.
Wanderley Dos Reis
Flávia
F
Luz
Lívia Silva
LS
Paz
Silvania Tavares
ST
Silva
Hilton Justino
HJ
Souza
Sandra Lopes
SL
Leandro
Carol Góis
CG
D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development; D018753:Diet, Protein-Restricted; D004044:Dietary Proteins; D005260:Female; D007774:Lactation; D007830:Larynx / Q000033:anatomy & histology* / Q000254:growth & development; D008297:Male; D044342:Malnutrition / Q000150:complications*; D051381:Rats; D013997:Time Factors; D014827:Vocal Cords / Q000033:anatomy & histology / Q000254:growth & development; D015430:Weight Gain
D004044:Dietary Proteins