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Modulation of baroreflex function by rosiglitazone in prediabetic hyperglycemic rats
1Department of Medical Education and Research, Taichung Veterans General Hospital, Taichung, Taiwan, ROC. lzhong@vghtc.gov.tw
Physiological Research
|August 14, 2012
Summary
Prediabetic hyperglycemia impairs baroreflex sensitivity (BRS). Rosiglitazone treatment normalized BRS and blood glucose levels in rats by modulating cardiac autonomic function.
Area of Science:
- Cardiovascular Physiology
- Endocrinology
- Pharmacology
Background:
- Baroreflex sensitivity (BRS) is often abnormal in prediabetic states.
- Hyperglycemia in prediabetes can impact cardiovascular autonomic function.
Purpose of the Study:
- To investigate the effects of chronic rosiglitazone (RSG) treatment on BRS in prediabetic hyperglycemic (PDH) rats.
- To determine if RSG can ameliorate BRS abnormalities and cardiovascular dysfunction associated with prediabetes.
Main Methods:
- Induction of prediabetic hyperglycemia in rats using nicotinamide and streptozotocin.
- Administration of rosiglitazone (RSG) or saline for 12 weeks.
- Assessment of phenylephrine-induced BRS (PE-BRS) and sodium nitroprusside-induced BRS (NP-BRS).
- Evaluation of cardiac autonomic influences via autonomic blockades.
Main Results:
- Saline-treated PDH rats showed enhanced PE-BRS early and increased abnormalities in NP-BRS and cardiac autonomic function by week 12.
- RSG treatment normalized blood glucose levels within 4 weeks but PE-BRS normalization required 12 weeks.
- All cardiovascular variables were fully restored after 12 weeks of RSG treatment.
- A significant correlation between BRS and blood glucose was observed in saline-treated rats, but not in RSG-treated rats.
Conclusions:
- Hyperglycemia, even in the prediabetic stage, contributes to baroreflex sensitivity abnormalities.
- Early administration of RSG can normalize BRS in prediabetic rats through cardiac autonomic modulation and anti-hyperglycemic effects.
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