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Neuromuscular junctions ( NMJ s): ultrastructural analysis and nicotinic acetylcholine receptor ( nAChR ) subunit mRNA expression in offspring subjected to protein restriction throughout pregnancy
Author(s) -
Castro Paula Aiello Tomé de Souza,
Faccioni Ludimila Canuto,
Boer Patrícia Aline,
Carvalho Robson Francisco,
Matheus Selma Maria Michelin,
DalPaiSilva Maeli
Publication year - 2017
Publication title -
international journal of experimental pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.671
H-Index - 72
eISSN - 1365-2613
pISSN - 0959-9673
DOI - 10.1111/iep.12229
Subject(s) - offspring , acetylcholine receptor , biology , neuromuscular junction , medicine , endocrinology , nicotinic acetylcholine receptor , postsynaptic potential , protein subunit , nicotinic agonist , receptor , neuroscience , biochemistry , pregnancy , genetics , gene
Summary Protein restriction during gestation can alter the skeletal muscle phenotype of offspring; however, little is known with regard to whether this also affects the neuromuscular junction ( NMJ ), as muscle phenotype maintenance depends upon NMJ functional integrity. This study aimed to evaluate the effects of a low protein (6%) intake by dams throughout gestation on male offspring NMJ morphology and nicotinic acetylcholine receptor ( nAChR ) α1, γ and ε subunit expression in the soleus ( SOL ) and extensor digitorum longus ( EDL ) muscles. Four groups of male Wistar offspring rats were studied. The offspring of dams fed low‐protein (6% protein, LP ) and normal protein (17% protein, NP ) diets were evaluated at 30 and 120 days of age, and the SOL and EDL muscles were collected for analysis. Morphological studies using transmission electron microscopy revealed that only SOL NMJ s were affected in 30‐day‐old offspring in the LP group compared with the NP group. SOL NMJ s exhibited fewer synaptic folds, the postsynaptic membranes were smooth and myelin figures were also frequently observed in the terminal axons. With regard to the expression of mRNA s encoding nAChR subunits, only 30‐day‐old LP offspring EDL muscles exhibited reduced α, γ and ε subunit expression compared with the NP group. In conclusion, our results demonstrate that a low‐protein diet (6%) imposed throughout pregnancy impairs the expression of mRNA s encoding the nAChR α, γ and ε subunits in EDL NMJ s and promotes morphological changes in SOL NMJ s of 30‐day‐old offspring, indicating specific differences among muscle types following long‐term maternal protein restriction.