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Is the preconditioning threshold different in females?
Jeffrey M Pitcher1, Ryan D Nagy, Ben M Tsai
1Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
The Journal of Surgical Research
|April 28, 2005
Summary
Endotoxin preconditioning protects against cardiac injury, but the effective dose differs between sexes. Females require a higher endotoxin dose for preconditioning compared to males to maintain cardiac function.
Area of Science:
- Physiology
- Cardiovascular Research
- Toxicology
Background:
- Preconditioning is an injury-induced protective mechanism against subsequent insults.
- Both male and female subjects can be preconditioned.
- Females exhibit innate cardioprotection, suggesting potential sex-based differences in preconditioning thresholds.
Purpose of the Study:
- To investigate sex-specific differences in endotoxin preconditioning thresholds.
- To determine if the dose of endotoxin required for preconditioning varies between male and female rats.
Main Methods:
- Male and female rats received varying doses of Salmonella typhimurium lipopolysaccharide (ETX) or saline.
- Animals were subjected to a second ETX injection (injury dose) after a 24-hour incubation period.
- Cardiac function was assessed using the Langendorff perfusion model.
Main Results:
- Female rats preconditioned with 500 µg/kg ETX maintained cardiac function similar to controls.
- Lower doses (125 µg/kg ETX) failed to precondition females, resulting in decreased cardiac function.
- Male rats showed cardiac protection at both 500 µg/kg and 125 µg/kg ETX doses, unlike the PC- group.
Conclusions:
- Endotoxin can precondition both male and female rats.
- The preconditioning threshold for endotoxin is higher in females than in males.