Related Experiment Videos
Effects of undernutrition and sex difference on skeletal muscle function in young rats
N Krishnamurthy1, B Balakumar, D P Thombre
1Department of Physiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry.
Insights
Early undernutrition prolonged skeletal muscle contraction and relaxation times in young rats. Sex differences in adulthood also affected muscle contractile characteristics differently across various muscles.
Area of Science:
- Physiology
- Muscle Biology
- Nutritional Science
Background:
- Skeletal muscle contractile properties are crucial for motor function.
- Undernutrition during development can have lasting physiological impacts.
- Sex-based differences in muscle physiology are well-documented but require further investigation under specific conditions.
Purpose of the Study:
- To investigate the impact of early-life undernutrition on skeletal muscle contractile characteristics in young rats.
- To examine sex-based differences in skeletal muscle contractile properties in adult rats.
- To determine if undernutrition and sex differences interact to influence muscle function.
Main Methods:
- Comparative analysis of gastrocnemius muscle contractile properties between undernourished and control rat groups.
- Assessment of sex-based differences in gastrocnemius, extensor digitorum longus, and soleus muscle contractile characteristics in adult rats.
- Measurement of contraction time, relaxation time, contraction force, and endurance time.
Main Results:
- Undernourished rats exhibited prolonged contraction and relaxation times in the gastrocnemius muscle compared to controls.
- Adult female rats showed prolonged contraction time in the gastrocnemius muscle compared to males.
- Females displayed reduced force production in gastrocnemius and extensor digitorum longus, and shorter endurance time in the soleus muscle compared to males.
Conclusions:
- Early-life undernutrition significantly alters skeletal muscle contractile properties, leading to prolonged contraction and relaxation.
- Sex differences manifest in adult rat skeletal muscles, affecting contractile force, time, and endurance.
- The study highlights the distinct and complex effects of both nutritional status and sex on muscle physiology.
Abstract:
The effects of undernutrition and sex difference on skeletal muscle contractile characteristics were studied in young albino rats. The skeletal muscle (gastrocnemius) of 8 week old pups with only one-third normal food intake (undernourished group = UN group; n = 18), as compared to free fed pups (control group = cont. group; n = 16), showed prolongation of contraction time (23.6 +/- 1.0 Vs 20.9 +/- 0.8 msec, Mean +/- SE, P < 0.05) and relaxation time (31.5 +/- 1.8 Vs 22.9 +/- 1.1 msec, P < 0.001) and retention of contraction force and endurance time. In 18 week old rats the effects of sex difference in females (n = 10), as compared to males (n = 10) were prolongation of contraction time in gastrocnemius (32.2 +/- 1.5 Vs 27.8 +/- 1.5 msec, P < 0.05), less force production in gastrocnemius (668.9 +/- 48.0 Vs 895.4 +/- 93.3 g, P < 0.05) and extensor digitorum longus (20.1 +/- 3.3 Vs 29.9 +/- 2.5 g, P < 0.05) and shorter endurance time (160.8 +/- 10.2 Vs 187.2 +/- 7.1 sec, P < 0.05) in soleus. Thus, it is concluded that early undernutrition has prolonged the contraction and relaxation times of the skeletal muscles and the effect of sex difference in the early adulthood was different in different skeletal muscles.