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Skeletal Muscle wasting and contractile performance in septic rats.
R Minnaard1, M R Drost, A J M Wagenmakers
1Nutrition and Toxicology Research Institute Maastricht, Depatment of Movement Sciencs, Maastricht University, 6200 MD Maastricht, The Netherlands. Ronnie.Minnaard@bw.unimaas.nl
Muscle & Nerve
|March 8, 2005
Summary
Sepsis causes significant muscle wasting and loss of function, primarily due to reduced muscle mass. This muscle wasting is fiber-type specific, affecting different muscle fibers differently.
Area of Science:
- Physiology
- Biochemistry
- Sepsis Research
Background:
- Sepsis is a life-threatening condition characterized by a dysregulated host response to infection.
- Muscle wasting and dysfunction are common complications of sepsis, impacting patient recovery and survival.
- The precise mechanisms and temporal dynamics of sepsis-induced muscle wasting remain incompletely understood.
Purpose of the Study:
- To investigate the temporal progression of muscle wasting and functional decline following sepsis induction.
- To determine the contribution of muscle mass reduction to the loss of muscle function during sepsis.
- To examine the fiber-type specificity of muscle wasting in response to sepsis.
Main Methods:
- Sepsis was induced in rats via intraperitoneal injection of zymosan.
- Muscle function was assessed using in situ electrical stimulation at various time points post-injection.
- Muscle wasting was quantified by measuring muscle mass and cross-sectional fiber area.
- Proteasome activity was measured in specific muscles.
Main Results:
- Zymosan injection led to severe muscle wasting compared to control groups.
- A significant reduction in isometric force-generating capacity was observed at 6 days post-sepsis, fully explained by muscle mass loss.
- Increased 20S proteasome activity was noted in the gastrocnemius but not soleus muscle at day 6.
- Muscle wasting exhibited fiber-type specificity in the tibialis anterior, with type 1 fibers being less affected than type 2A and 2B/X fibers.
Conclusions:
- Sepsis-induced decline in muscle function is primarily driven by the loss of muscle mass.
- Muscle wasting in sepsis is fiber-type specific, indicating differential susceptibility among fiber types.
- A muscle's inherent function and fiber-type composition influence its response to catabolic signals during sepsis.