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Published on: July 13, 2014
Prenatal alcohol exposure and early postnatal changes in the developing nerve-muscle system
Pamela David1, Krishnan Subramaniam
1Department of Anatomy, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
Insights
Prenatal alcohol exposure in rats resulted in delayed neuromuscular system maturation, evidenced by polyneuronal innervation and reduced muscle growth. This confirms alcohol
Area of Science:
- Neuroscience
- Developmental Biology
- Toxicology
Background:
- Prenatal alcohol exposure is a known teratogen, leading to Fetal Alcohol Syndrome (FAS).
- Fetal alcohol syndrome is associated with muscle weakness, wasting, and atrophy.
- The impact of prenatal alcohol on the developing rat neuromuscular system was investigated.
Purpose of the Study:
- To assess the effects of prenatal alcohol exposure on the developing rat neuromuscular system.
- To investigate alterations in muscle development and nerve innervation patterns.
Main Methods:
- Pregnant Sprague-Dawley rats received intraperitoneal injections of ethyl alcohol.
- Offspring were analyzed at 2, 3, 4, and 5 weeks post-birth.
- Muscle weights, fiber size/number, and nerve myelin patterns were quantified and analyzed.
Main Results:
- Alcohol-exposed rats exhibited a higher proportion of polyneuronally innervated neuromuscular junctions.
- Significant reductions in muscle weight, fiber number, and fiber size were observed.
- Alterations in myelin connectivity were detected in the sciatic nerves of exposed rats.
Conclusions:
- Polyneuronal innervation suggests a delay in neuromuscular system maturation.
- Prenatal alcohol exposure has detrimental effects on nerve-muscle system growth and maturation.
- These findings highlight the neurotoxic effects of alcohol during development.
Background:
Extensive research on prenatal alcohol exposure has proven the potent teratogenicity of this substance of abuse. Children born to alcoholic mothers are often diagnosed with fetal alcohol syndrome (FAS). Those afflicted with FAS often have muscle weakness, muscle wasting, and atrophy. This study assessed the effects of prenatal alcohol exposure on the developing rat neuromuscular system.
Methods:
Pregnant Sprague-Dawley rats were injected intraperitoneally with 1.0 ml of 20% ethyl alcohol/100 gm body weight. Unexposed rats served as controls. The offspring were killed 2, 3, 4, and 5 weeks after birth, and their body weights were recorded. The tibialis anterior (TA) and extensor digitorum longus (EDL) muscles were recovered and weighed. The TA muscles were histochemically stained by silver cholinesterase in order to study the pattern of innervation. The EDL muscles were processed and stained by hematoxylin-eosin. The number and size of the EDL muscle fibers was quantified. The sciatic nerve was also removed and stained by Swank and Davenport's method to demonstrate the myelin pattern.
Results:
Assessment at the neuromuscular junction showed a higher proportion of endplates polyneuronally innervated in the alcohol-exposed rats. The muscle weights, as well as the number and size of the muscle fibers, were significantly reduced in these animals. A light-microscopy examination of the nerve sections revealed alterations in the connectivity of myelin.
Conclusions:
The finding that a higher proportion of endplates were polyneuronally innervated in the alcohol-exposed rats indicates that the maturation process of the neuromuscular system was delayed, thus confirming the deleterious effects of alcohol on growth and maturation of the nerve-muscle system.
