Related Experiment Videos
Effect of undernutrition on contractile and fatigue properties of rat diaphragm during development
B S Brozanski1, J F Watchko, T L O'Day
1Department of Pediatrics, University of Pittsburgh School of Medicine, Pennsylvania 15213.
Insights
Combined pre- and postnatal undernutrition stunted rat growth but enhanced diaphragm muscle fatigue resistance. Contractile properties remained largely unaffected in undernourished (UN) versus control (CTL) groups.
Area of Science:
- Physiology
- Developmental Biology
- Nutritional Science
Background:
- Undernutrition during development can impact organ function.
- The diaphragm's contractile and fatigue properties may be sensitive to nutritional status.
Purpose of the Study:
- To investigate the effects of combined pre- and postnatal undernutrition on rat diaphragm function.
- To assess changes in contractile and fatigue properties during postnatal development.
Main Methods:
- In vitro direct stimulation of rat costal diaphragm.
- Comparison between control (CTL) and undernourished (UN) groups across multiple postnatal ages (days 1-60).
Main Results:
- Undernutrition caused stunted growth but maintained diaphragm-to-body weight ratio.
- Diaphragm contractile properties (twitch, tetanic force, relaxation times) were not significantly altered.
- Fatigue resistance was comparable early on but significantly higher in UN rats from day 14 onwards.
Conclusions:
- Combined pre- and postnatal undernutrition enhances diaphragm fatigue resistance.
- Diaphragm contractile function is resilient to prolonged undernutrition during development.
Abstract:
The present study was designed to assess the effects of combined pre- and postnatal undernutrition on the in vitro contractile and fatigue properties of the rat diaphragm during development. In vitro direct stimulation of costal diaphragm from control (CTL) and undernourished (UN) rats was done on postnatal days 1, 4, 14, 21, 30, 40, 50, and 60. Combined pre- and postnatal undernutrition resulted in stunted animal growth but did not alter the diaphragm-to-total body weight ratio. Twitch contraction time, half-relaxation time, and force-frequency relationships were not consistently affected by undernutrition. Specific twitch force and specific tetanic force were also unchanged in the UN group. Fatigue resistance was high and comparable in UN and CTL groups at days 1 and 4. At day 14 and thereafter, fatigue resistance declined but was consistently higher in the UN than in the CTL group. We conclude that combined pre- and postnatal undernutrition results in a significant increase in fatigue resistance of the diaphragm compared with CTL, whereas diaphragm muscle contractile properties are not appreciably affected by prolonged undernutrition.