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BACKGROUND AND AIM: β3 receptor β1, β2 receptor belong to β-adrenergic receptor (referred to as β receptor) family members, the structure and function of the three subtypes have certain similarities, there was an interaction between them. When retardation or agitation of a subtype, other subtypes of expression may be affected subsequently. β3 receptor in fatty tissue, the highest density, mainly involved in the degradation of fat tissue triglyceride, to generate energy. Normal myocardial tissue, β1, β2 receptor dominant of β3 receptor mRNA expression was very. Heart failure (heart failure, HF) β1 receptor expression cut the β3 receptor upregulation 2-3 times, the front portion of the subjects of the study also confirmed the β3 receptor expression are increased after myocardial infarction (myocardial infarction, MI), speculated that the pathophysiological changes the process of its participation in post-MI. Cardiac remodeling (cardiac remodeling, CRM) is considered to be a major pathophysiological changes in the process of after MI, myocardial necrosis, apoptosis, re-expression of embryonic genes and proteins, increased secretion of inflammatory cytokines, clinical performance for the wall becomes thin ventricular volume increase infarct zone expansion Exhibition, ventricular oval to round or irregular in shape, myocardial cells adapt to the adverse hypertrophy. Non-infarcted myocardium hypertrophy ventricular compliance and force of contraction, and to affect ventricular systolic and diastolic function. beta blockers have a role in the prevention and reversal of MI and cardiac hypertrophy, mainly through the inhibition of the neuroendocrine effects and reduce the toxic effects of catecholamines, the relationship between this role and β3 receptor remains unclear. The topics chosen selective β1 receptor blocker metoprolol,, nonselective β receptor and alpha-blocker carvedilol selective β3 agonist of BRL37344 role in MI rats, observed MI The cardiac hypertrophy myocardial hypertrophy and the relationship between the amount of the β3 receptor expression and metoprolol, carvedilol and BRL37344 intervention β3 receptor expression levels and cardiac function. Materials and methods: (1) Animal grouping and model to establish 130 :200-250 g Sprague Dawley male rats were randomly divided into three groups: normal group (normal) 10, sham group (sham operated) 10, MI group (MI-). Ligating left anterior descending coronary artery (left anterior descending, LAD) to establish the MI model, I survived 2 h mark, and were randomly divided into 6 groups 52, the last surviving rats: MI intervention in the control group (MI-1) 8, MI distilled water control group (MI-2) 8, MI add distilled intraperitoneal injection of the control group, (MI-3) 8 only, the the MI plus metoprolol gavage group (MI-4) 11 Zhi, MI Jia Kawei carvedilol gavage group (MI-5) 10 Zhi, MI plus the BRL37344 intraperitoneal injection group (MI-6) 7 Zhi. sham group operating in the MI group, playing a loose knot, not truss LAD. Weight of 8 rats were: normal group 224.2 ± 18.4 g, the sham group 233.6 ± 19.4 g, MI-1 group 229.8 ± 18.0 g, 233.6 ± 22.5 g MI-2 group, MI-3 group was 226.8 ± 15.7 g MI-5, MI-4 group, 232.3 ± 20.3 g, 233.7 ± 23.5 g, 233.6 ± 18.1 g of MI-6 group, each group of body weight undifferentiated. (2) postoperative medication and hemodynamic monitoring: MI-1 non-intervention control group, MI-2, MI-3 were distilled water and intraperitoneal injection of MI-4, MI-5 group, respectively, to the United States Trotsky of Seoul 20 mg / kg BM / day, carvedilol 10 mg / kg BM / day orally, MI-6 group to of BRL37344 1.5μmol/kg BM / day divided into two administration, rats in each group to normal diet. MI-2 as the control group of the MI-4, and MI-5 and MI-3 MI-6, the control group, the MI-1, the control group, the MI-2 and MI-3 collectively MI. 12 w after medication, the right femoral artery catheterization and right common carotid artery to the left indoor monitoring of hemodynamic parameters: heart rate (heart rate, HR), mean arterial blood pressure (mean blood pressure, MBP), left ventricular systolic pressure (left ventricular systolic pressure, LVSP), left ventricular pressure rise and fall rate (maximum rise or fall rate of left ventricular pressure, ± dp / dt max). (3) Determination of left and right ventricular relative weight index and β3 receptor expression amount: were decapitated immediately after the heart was removed, removal of the atria, the vascular roots and fibrous tissue, known as the left and right ventricular weight, respectively, before the rats were killed and weight (body mass, BM) compared to calculate the left and right ventricular relative importance index (LVBM, RVBM), for the description of the left and right ventricular hypertrophy, Western blot (Western-blot) and reverse transcription polymerase chain reaction ( RT-PCR) detection of left ventricular infarct zone β3 receptor expression at the protein level and mRNA levels. (4) Statistical analysis: The experimental results using the SPSS 13.0 statistical software analysis, and the results are expressed as mean ± standard deviation (x ± s) said, the use of single-factor analysis of variance (one-way analysis of variance, one-way ANOVA) between groups comparison. P lt; 0.05 indicates a statistically significant difference. Results: (1) after MI cardiac hypertrophy: normal group and sham group LVBM were 2.188 ± 0.107,2.209 ± 0.126, respectively 0.557 ± 0.024,0.551 ± 0.029, RVBM the two groups LVBM and RVBM were no difference (P gt ; 0.05), surgical intervention does not affect LVBM RVBM sham group instead of the normal group and the MI group compared. Compared with the sham group, MI control group LVBM (as 2.529 ± 0.152,2.545 ± 0.252,2.596 ± 0.262) was significantly increased (P lt; 0.01), the difference between the two groups was statistically significant (P gt; 0.05); compared with sham group MI control group RVBM (as 0.969 ± 0.057,0.966 ± 0.051,0.984 ± 0.077, respectively) was significantly increased (P lt; 0.01), the difference between the two groups had no statistical significance (P gt; 0.05). (2) MI β3 receptor expression amount of the change: the amount of the expression of the sham group, compared with other groups. Sham group at the protein level, normal group (0.98 ± 0.14) and no difference (P gt; 0.05); expression of the MI control group (2.08 ± 0.25,2.00 ± 0.29,2.02 ± 0.33) compared to the sham group were significantly increased ( P lt; 0.01), no difference between the MI control group (P gt; 0.05). Sham group no difference in mRNA levels, normal group (0.96 ± 0.10) (P gt; 0.05); MI control group (1.69 ± 0.34,1.68 ± 0.37,1.7 ± 0.39) compared with sham group was significantly increased (P lt ; 0.01), the difference between the two groups was not statistically significant (P gt; 0.05). (3) MI hemodynamic changes: the normal group and sham group dp / dt max were 7092.9 ± 454.9,7072.6 ± 420.0, -dp/dt max respectively is 5460.3 ± 544.5,5251.3, ± 505.3, the two groups no difference statistically significant (P gt; 0.05). MI control group dp / dt max were of 3950.6 ± 387.7,3932.7 ± 513.5,4041.6 ± 439.7 for 2982.3 ± 343.6,2919.6 ± 398.7,2975.6 ± 346.6, -dp/dt max compared with sham group were significantly decreased (P lt; 0.01), no difference between the MI control group (P gt; 0.05). (4) metoprolol, carvedilol and BRL37344 intervention on myocardial hypertrophy, β3 receptor expression levels and the impact of changes in cardiac function the: ① MI-4, MI-5 and MI-6 group LVBM were 2.431 ± 0.157 , 2.525 ± 0.248,2.537 ± 0.209, compared to the sham group was significantly increased (P lt; 0.01), but no difference in MI control group (P gt; 0.05) between the three groups, no difference (P gt; 0.05); MI The -4, MI-5 and MI-6 group RVBM is 0.851 ± 0.056,0.649 ± 0.060,0.654 ± 0.054, respectively, compared with sham group was significantly increased (P lt; 0.01), compared with MI reduce the control group (P lt; 0.01), MI-5, MI-6 group with MI-4 group difference significant (P lt; 0.01), between the two groups no difference (P gt; 0.05). ② to the sham group β3 receptor expression at the protein level, the expression of MI-4 group was 1.99 ± 0.26, the metoprolol intervention has no effect after MI β3 receptor expression (P gt; 0.05); MI -5 and MI-6 expression were 3.12 ± 0.55,3.36 ± 0.45, carvedilol and BRL37344 intervention are further raised after MI β3 receptor expression (P lt; 0.01), MI-5, MI-6 The group with MI-4 group was significantly different (P lt; 0.01). MI-4, MI-5 and MI-6 group the β3 receptor mRNA expression levels were further increased the β3 receptor mRNA expression (P lt 2.01 ± 0.32,2.74 ± 0.58,2.84 ± 0.51,3 drug intervention; 0.01), the role of Carvedilol and BRL37344 strong compared with metoprolol (P lt; 0.01). ③ the MI-4, MI-5 and MI-6 dp / dt max to 6293.2 ± 447.0,6394.5 ± 553.3,6152.7 ± 493.2 -dp/dt max 4084.9 ± 320.8,4271.5 ± 256.5,3930.8 ± 370.0,3 ± dp / dt max drugs after the intervention compared with MI control group was significantly higher (P lt; 0.01), but has not yet reached the level of the sham group (P lt; 0.01). Conclusion: (1) ligation of the left anterior descending artery after 12 weeks, the non-infarcted area of ??the left ventricle and right ventricle are apparent cardiac hypertrophy, left ventricular systolic and diastolic dysfunction. (2) in rats after myocardial infarction left ventricular non-infarcted area the β3 receptor protein and mRNA expression were significantly increased. (3) metoprolol, carvedilol and BRL37344 intervention not improve after myocardial infarction, left ventricular hypertrophy, improved to varying degrees of right ventricular myocardial hypertrophy than metoprolol, carvedilol and BRL37344 effect . Metoprolol no raised the role of β3 receptor protein expression the Carvedilol and BRL37344 can raise the β3 receptor protein expression; metoprolol, carvedilol and BRL37344 can increase the β3 receptor mRNA expression The the Carvedilol and BRL37344 role of strong metoprolol. Three can improve ventricular systolic and diastolic function after myocardial infarction. (4) the amount of improvement speculated after myocardial infarction, right ventricular hypertrophy and β3 receptor protein expression upregulation, its mechanism is not yet clear, and may β3 receptor antifibrotic, anti-apoptotic, promote angiogenesis, improve myocardial blood evidence and metabolic effects.
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