OBJECTIVETo investigate the mRNA and protein expression of mineralocorticoid receptor (MR) in patients with atrial fibrillation.

METHODSTwenty-five patients with rheumatic heart valve disease, 12 in sinus rhythm and 13 in chronic atrial fibrillation (>or= 6 months), underwent transthoracic echocardiography and right and left atrial lateral wall tissue samples were obtained from these patients during mitral/aortic valve replacement operation. Realtime quantitative PCR and Western blot were used to determine the mRNA and protein expression of MR in atria specimens. The distribution of MR in human atria was analyzed by specific immunohistochemical staining.

RESULTSThe left atrial diameters increased markedly in atrial fibrillation group compared with that in sinus rhythm group (P<0.01). And the results showed that the level of mRNA and protein of MR were increased significantly in atrial fibrillation group compared with those in sinus rhythm group (P<0.01 or 0.05), whereas the expression of mRNA and protein of MR were found to be no difference between left atria and right atria both in fibrillation and sinus groups (all P>0.05). The special immunohistochemical staining demonstrated that MR was abundant in the human atrial myocardium and MRs were located mainly in the cytoplasm of atrial cells, which were more evident in atrial fibrillation group than those in sinus rhythm group.

CONCLUSIONThese findings suggested that MRs were upregulated in atrial fibrillation and aldosterone antagonists may be effective in treating atrial fibrillation.

Adult ; Atrial Fibrillation ; metabolism ; Humans ; Male ; Middle Aged ; Myocardium ; metabolism ; RNA, Messenger ; genetics ; Receptors, Mineralocorticoid ; metabolism

OBJECTIVE: To observe the effect of wheat-grain moxibustion on behavior, 5-hydroxytryptamine (5-HT) and cortisol in the serum, mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) in the hippocampus in rats with hypothyroidism complicated with depression, and to explore the possible mechanism of wheat-grain moxibustion on improving depression in rats with hypothyroidism. METHODS: A total of 32 SPF SD rats were randomly divided into a blank group, a model group, a medication group and a wheat-grain moxibustion group, 8 rats in each group. Except for the blank group, the rats in the remaining groups were treated with intragastric administration of 0.1% propylthiouracil (PTU) suspension at 1 mL/100 g, once a day for 4 weeks to establish the rat model of hypothyroidism, and whether the rats were accompanied with depression-like behavior determined through behavioristics evaluation. The rats in the medication group were intervened with euthyrox at 0.9 mL/100 g, once a day, for 4 weeks; the rats in the wheat-grain moxibustion group were treated with wheat-grain moxibustion at "Dazhui" (GV 14), "Mingmen" (GV 4), "Shenshu" (BL 23) and "Pishu" (BL 20), 7 cones each acupoint, once a day, six times a week for 4 weeks. After the intervention, the depression status was observed by behavioristics test; the contents of thyroid stimulating hormone (TSH), total thyroxine (TT4), 5-HT and cortisol in the serum were detected by ELISA; the protein expressions of MR and GR in hippocampus were detected by Western blot; the expressions of MR mRNA and GR mRNA in the hippocampus were detected by real-time PCR. RESULTS: Before the intervention, compared with the blank group, the scores of open field test (OFT) were decreased and the immobility time of tail suspension test (TST) was prolonged (P<0.05); the serum TSH contents were increased and TT4 contents were decreased (P<0.01) in the other three groups. After the intervention, compared with the model group, the vertical score of OFT was increased and the immobility time of forced swimming test (FST) was prolonged in the medication group (P<0.05), while the scores of three items of OFT were increased (P<0.05, P<0.01), and the immobility time of FST and TST was shortened in the wheat-grain moxibustion group (P<0.01, P<0.05). Compared with the medication group, the immobility time of TST and FST in the wheat-grain moxibustion group was shorter (P<0.05, P<0.01). Compared with the blank group, in the model group, the contents of serum TSH and cortisol were increased (P<0.01, P<0.001), while the contents of serum TT4 and 5-HT were decreased (P<0.01, P<0.001). Compared with the model group, the contents of serum TT4 and 5-HT were increased, while the contents of serum TSH and cortisol were decreased in the medication group and wheat-grain moxibustion group (P<0.01, P<0.05). Compared with the blank group, the protein and mRNA expression of MR, GR in the hippocampus in the model group was decreased (P<0.01, P<0.05, P<0.001); compared with the model group, the protein and mRNA expression of MR in the hippocampus in the medication group were increased (P<0.05), and the protein expression of MR, GR and mRNA expression of MR in the hippocampus in the wheat-grain moxibustion group were increased (P<0.05, P<0.01). Compared with the medication group, the expression of MR mRNA in the wheat-grain moxibustion group was increased (P<0.05). CONCLUSION Wheat-grain moxibustion could significantly improve thyroid function and depression in rats with hypothyroidism. Its mechanism may be related to up-regulating the protein and mRNA expression of MR and GR in the hippocampus, and then affecting the expression of serum cortisol and 5-HT.
Acupuncture Points ; Animals ; Depression/therapy* ; Hippocampus/metabolism* ; Hydrocortisone/metabolism* ; Hypothyroidism/therapy* ; Moxibustion ; RNA, Messenger/metabolism* ; Rats ; Rats, Sprague-Dawley ; Receptors, Glucocorticoid/metabolism* ; Receptors, Mineralocorticoid/metabolism* ; Serotonin ; Thyrotropin/metabolism* ; Triticum/metabolism*

Emerging evidence indicates that aldosterone and mineralocorticoid receptors (MRs) are associated with the pathogenesis of erectile dysfunction. However, the molecular mechanisms remain largely unknown. In this study, freshly isolated penile corpus cavernosum tissue from rats was treated with aldosterone, with or without MRs inhibitors. Nuclear factor (NF)-kappa B (NF-κB) activity was evaluated by real-time quantitative PCR, luciferase assay, and immunoblot. The results demonstrated that mRNA levels of the NF-κB target genes, including inhibitor of NF-κB alpha (IκB-α), NF-κB1, tumor necrosis factor-alpha (TNF-α), and interleukin 6 (IL-6), were higher after aldosterone treatment. Accordingly, phosphorylation of p65/RelA, IκB-α, and inhibitor of NF-κB kinase-β was markedly increased by aldosterone. Furthermore, knockdown of MRs prevented activation of the NF-κB canonical pathway by aldosterone. Consistent with this finding, ectopic overexpression of MRs enhanced the transcriptional activation of NF-κB by aldosterone. More importantly, the MRs antagonist, spironolactone blocked aldosterone-mediated activation of the canonical NF-κB pathway. In conclusion, aldosterone has an inflammatory effect in the corpus cavernosum penis, inducing NF-κB activation via an MRs-dependent pathway, which may be prevented by selective MRs antagonists. These data reveal the possible role of aldosterone in erectile dysfunction as well as its potential as a novel pharmacologic target for treatment.
Aldosterone/pharmacology* ; Animals ; Cytokines/biosynthesis* ; Gene Knockdown Techniques ; I-kappa B Kinase/antagonists & inhibitors* ; Interleukin-6/genetics* ; Male ; Mineralocorticoid Receptor Antagonists/pharmacology* ; NF-kappa B/genetics* ; Penis/metabolism* ; Protein Serine-Threonine Kinases/antagonists & inhibitors* ; RNA, Messenger/biosynthesis* ; Rats ; Rats, Inbred WKY ; Receptors, Mineralocorticoid/genetics* ; Signal Transduction/drug effects* ; Spironolactone/pharmacology* ; Transcriptional Activation ; Tumor Necrosis Factor-alpha/biosynthesis* ; NF-kappaB-Inducing Kinase

The effect of aldosterone on connective tissue growth factor (CTGF) was examined in rat embryonic ventricular myocytes. Upon aldosterone treatment, CTGF expression was significantly increased in a dose and time-dependent manner. To explore the molecular mechanism for this upregulation, we examined the role of mineralocorticoid receptor. Pre-treatment of an antagonist (spironolactone) at 5-fold excess of aldosterone blocked the CTGF induction by aldosterone, suggesting that the upregulation was mediated by mineralocorticoid receptor. Aldosterone treatment resulted in activation of ERK1/2, p38 MAPK, and JNK pathways with a more transient pat-tern in p38 MAPK. Blocking studies using pre-treatment of the inhibitor of each path-way revealed that p38 MAPK cascade may be important for aldosterone-mediated CTGF upregulation as evidenced by the blocking of CTGF induction by SB203580 (p38 MAPK inhibitor), but not by PD098059 (ERK1/2 inhibitor) and JNK inhibitor I. Interestingly, JNK inhibitor I and PD098059 decreased the basal level of CTGF expression. On the other hand, pre-treatment of spironolactone abrogated the p38 MAPK activation, indicating that mineralocorticoid receptor mechanism is linked to p38 MAPK pathway. Taken together, our findings suggest that aldosterone induces CTGF expression via both p38 MAPK cascade and mineralocorticoid receptor and that cross-talk exists between the two pathways.
Aldosterone/*pharmacology ; Animals ; Cells, Cultured ; Dose-Response Relationship, Drug ; Gene Expression Regulation/drug effects/physiology ; Heart Ventricles/drug effects/embryology/metabolism ; Immediate-Early Proteins/*metabolism ; Intercellular Signaling Peptides and Proteins/*metabolism ; Myocytes, Cardiac/*drug effects/*metabolism ; Rats ; Receptors, Mineralocorticoid/*metabolism ; Research Support, Non-U.S. Gov't ; Signal Transduction/drug effects/physiology ; Spironolactone/pharmacology ; Up-Regulation/drug effects/physiology ; p38 Mitogen-Activated Protein Kinases/*metabolism

OBJECTIVETo investigate the effect of losartan on cardiac mineralocorticoid receptor (MR) mRNA in rats after acute myocardial infarction (AMI).

METHODAMI was induced in male SD rats by ligation of the left coronary artery. The survived rats were randomly divided into AMI group, losartan group, and sham-operated group. The cardiac functions of the rats were assessed by echocardiogram and hemodynamics, and the contents of angiotensin II (Ang II) and aldosterone (Ald) in the myocardial tissues were determined by radioimmunoassay. The collagen density in the myocardial tissues were calculated by Masson's trichrome staining and the expression of MR mRNA were determined by real-time quantitative fluorescent PCR.

RESULTSBoth the contents of AngII and Ald in the myocardial tissues increased significantly in AMI group compared with those in the sham-operated group (P<0.01). The expression of MR mRNA and collagen density in the myocardial tissues also increased significantly than that in sham-operated group (P<0.01). After four weeks of losartan treatment, the contents of AngII and Ald in the myocardial tissues decreased significantly (P<0.05) and the expression of MR mRNA was also considerably lowered (P<0.01) in comparison with those in the AMI group. Treatment with losartan also resulted in significant decrease of the collagen density in the myocardial tissues.

CONCLUSIONSLosartan may reduce reactive fibrosis not only by attenuating the Ald signaling pathway but also by decreasing the expression of MR.

Aldosterone ; metabolism ; Angiotensin II ; metabolism ; Angiotensin II Type 1 Receptor Blockers ; therapeutic use ; Animals ; Fibrosis ; etiology ; prevention & control ; Losartan ; therapeutic use ; Male ; Myocardial Infarction ; drug therapy ; metabolism ; Myocardium ; pathology ; RNA, Messenger ; genetics ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Receptors, Mineralocorticoid ; genetics ; metabolism