Regulatory Effects of Nitric Oxide and Angiotensin II on Myocardial Ischemia and Expression of Vascular Endothelial Growth Factor in Rats
Bibliographic record
Abstract
Objective:To investigate the regulatory effects of nitric oxide(NO) and angiotensin II(Ang II) on myocardial ischemia and the expression of vascular endothelial growth factor in rats.Methods: Thirty Sprague-Dawley rats were randomized into five groups(n=6 each),including the control group(COL,group A),the isoproterenol group(ISO,group B),the isoproterenol + losartan group(LOS,group C),the isoproterenol + N-nitro-L-arginine group(L-NNA,group D) and the isoproterenol + losartan + N-nitro-L-arginine group(LOS+L-NNA,group E).Acute myocardial ischemia model was induced with isoproterenol(ISO).N-nitro-L-arginine(L-NNA) was used to block the nitric oxide synthase(NOS),as was losartan(LOS) to block the AT1 receptor.Cardiac function was measured with a BL-420 biological signal processing system,contents of NO and creatine kinase(CK) measured by biochemistry methods,myocardial injury studied by HE stained histopathology,and expressions of VEGF and endothelial nitric oxide synthase(eNOS) analyzed by immunohistochemistry.RT-PCR was employed to detect the VEGF mRNA and eNOS mRNA in myocardium.Results: Compared with groups B,D and E,group C showed improved cardiac functions,attenuated myocardial damages(P0.01) and increased content of nitric oxide(P0.01).Enhanced expressions of VEGF mRNA and protein were also noted in C group compared with the other groups(P0.01).The levels of eNOS mRNA and protein expression were higher in groups C and E than in groups C and D(P0.01).Conclusion: Blockade of Ang II type 1 receptor was shown to up-regulate VEGF expression in rat myocardium.Nitric oxide and angiotensin II type 1 receptor signaling pathway may be playing a critical role in regulating VEGF expression.Losartan appeared protective for myocardium partly due to its regulation on VEGF and eNOS expressions and nitric oxide activity.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".