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Published on: March 13, 2012
Pressure hyperalgesia in hind limb suspended rats
Parimal Chowdhury1, Michael E Soulsby, John Jayroe
1Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
Aviation, Space, and Environmental Medicine
|October 4, 2011
Summary
Simulated microgravity in rats caused insulinopenia and pressure hyperalgesia, similar to prediabetes models. Hind limb suspension (HLS) reduced insulin levels and pain thresholds, suggesting peripheral neuropathy.
Area of Science:
- Spaceflight research
- Physiology
- Neurology
Background:
- Spaceflight and simulated microgravity are linked to pain and prediabetes.
- Streptozotocin (STZ)-induced insulinopenia in rats causes pressure hyperalgesia.
Purpose of the Study:
- To investigate if simulated microgravity via hind limb suspension (HLS) induces insulinopenia and pressure hyperalgesia in rats.
- To explore the relationship between insulin levels and pain sensitivity under simulated microgravity.
Main Methods:
- Adult male rats were divided into HLS and control groups.
- Bodyweight and hind limb pressure-pain withdrawal threshold (PPT) were measured before and after HLS.
- Plasma insulin levels were analyzed.
Main Results:
- HLS rats gained less weight and showed a significant decline in PPT compared to controls.
- HLS rats exhibited significantly lower random plasma insulin levels than control animals.
- Blood glucose, pancreatic islet density, and area were unaffected by HLS.
Conclusions:
- Simulated microgravity (HLS) in rats leads to insulinopenia and increased sensitivity to pressure pain.
- The findings suggest moderate insulinopenia directly impacts pain sensitivity, potentially causing peripheral neuropathy.
- These results offer insights into spaceflight-associated health risks, including pain and metabolic changes.
