Euglycemic therapy restores baroreflex dysfunction in rats with early diabetes
| Autor: | Hsin-Ru Liu, 劉欣茹 |
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| Rok vydání: | 2015 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 103 Diabetes-associated autonomic dysfunction is one of the major causes of mortality and morbidity in diabetic patients. Arterial baroreflex sensitivity (BRS), an index of cardiac autonomic function, was impaired in prediabetes and diabetes. Hyperglycemia has been implicated as a pathogenic factor for diabetic autonomic dysfunction. In this study, we assessed the changes of BRS and heart rate variability (HRV) in experimental diabetic rats. Diabetes was induced by intraperitoneal injection of streptozotocin in 20 adult male Wistar Kyoto (WKY) rats (aged 8 weeks). Twenty-one age-matched male WKY rats were used as control after intraperitoneal injection of same amount of normal saline. All the animals received weekly check of blood sugar. Diabetes mellitus (blood sugar >250mg/dL) occurred 10~12 weeks after the induction. ECG was recorded with subcutaneous electrodes and arterial blood pressure were acquired via intra-arterial implantation of a tonometry in the right femoral artery. After 30-minute recording, the animals received intravenous injection of phenylephrine for traditional pharmacological assessment of BRS (BRSdrug). After a complete recording, the rats received subcutaneous injection of insulin till the blood sugar below 200 mg/dL, then received similar assessment at euglycemic state. The BRSdrug were undetectable at hyperglycemic state then approached to the values of the normal rats at euglycemic state. Similar changes of BRS were noted on the BRS measured by spontaneous sequencing technique. Meanwhile, HRV indicated as low frequency power to high frequency power ratio (LHR) by fast Fourier transform, also decreased at hyperglycemic state than increased after insulin treatment although there is no statistic significance. On the other hand, animals received intravenous injection of glucose water to get a hyperglycemic state did not have similar changes of BRS. However, the hyperglycemic rats had higher LHR as compared with the normal did. In this study, we demonstrated that autonomic dysfunction and impaired baroreflex activity occurs in early diabetes can be restored by insulin therapy, additionally, the changes may be caused by diabetes process but hyperglycemia per se. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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