Baicalin inhibits toll-like receptor 2/4 expression and downstream signaling in rat experimental periodontitis.

Periodontitis is a severe inflammatory response, leading to characteristic periodontal soft tissue destruction and alveolar bone resorption. Baicalin possesses potent anti-inflammatory activity; however, it is still unclear whether baicalin regulates toll-like receptor (TLR) 2/4 expression and downstream signaling during the process of periodontitis. In this study, the cervical area of the maxillary second molars of rats was ligated and inoculated with Porphyromonas gingivalis (P. gingivalis) for 4weeks to induce periodontitis. Some rats with periodontitis were treated intragastrically with baicalin (50, 100 or 200mg/kg/day) or vehicle for 4weeks. Compared with the sham group, the levels of TLR2, TLR4 and MyD88 expression and the p38 MAPK and NF-κB activation were up-regulated in the experimental periodontitis group (EPG), accompanied by marked alveolar bone loss and severe inflammation. Treatment with 100 or 200mg/kg/day baicalin dramatically reduced the alveolar bone loss, the levels of HMGB1, TNF-α, IL-1ß, and MPO expression, and the numbers of inflammatory infiltrates in the gingival tissues. Importantly, treatment with 100 or 200mg/kg/day baicalin mitigated the periodontitis-up-regulated TLR2, TLR4 and MyD88 expression, and the p38 MAPK and NF-κB activation. Hence, the blockage of the TLR2 and TLR4/MyD88/p38 MAPK/NF-κB signaling by baicalin may contribute to its anti-inflammatory effects in rat model of periodontitis. In conclusion, these novel findings indicate that baicalin inhibits the TLR2 and TLR4 expression and the downstream signaling and mitigates inflammatory responses and the alveolar bone loss in rat experimental periodontitis. Therefore, baicalin may be a potential therapeutic agent for treatment of periodontitis.

Improving vagal activity ameliorates cardiac fibrosis induced by angiotensin II: in vivo and in vitro.

Cardiac remodeling is characterized by overactivity of the renin-angiotensin system (RAS) and withdrawal of vagal activity. We hypothesized that improving vagal activity could attenuate cardiac fibrosis induced by angiotensin II (Ang II) in vivo and in vitro. Rats were subjected to abdominal aorta constriction (AAC) with or without pyridostigmine (PYR) (31 mg/kg/d). After 8 weeks, PYR significantly decreased Ang II level, AT1 protein expression, and collagen deposition in cardiac tissue and improved heart rate variability, baroreflex sensitivity and cardiac function, which were abolished by atropine. In vitro, treatment of cardiac fibroblasts (CFs) with Ang II (10(-7) M) increased cell proliferation, migration, transformation, and secretory properties, which were significantly diminished by acetylcholine (ACh, 10(-6) M). Subsequently, Ang II significantly increased collagen type I expression as well as metalloproteinase (MMP)-2 expression and activity. Transforming growth factor (TGF)-ß1 expression and Smad3 phosphorylation presented a similar trend. Notably, the knockdown of the acetylcholine M2 receptor by siRNA could abolish ACh anti-fibrotic action. These data implicated cholinesterase inhibitor can increase vagal activity and reduce local Ang II level, and ACh inhibit Ang II pro-fibrotic effects. Our findings suggested that the parasympathetic nervous system can serve as a promising target for cardiac remodeling treatment.

Protective effects of extracts from Pomegranate peels and seeds on liver fibrosis induced by carbon tetrachloride in rats.

BACKGROUND: Liver fibrosis is a feature in the majority of chronic liver diseases and oxidative stress is considered to be its main pathogenic mechanism. Antioxidants including vitamin E, are effective in preventing liver fibrogenesis. Several plant-drived antioxidants, such as silymarin, baicalin, beicalein, quercetin, apigenin, were shown to interfere with liver fibrogenesis. The antioxidans above are polyphenols, flavonoids or structurally related compounds which are the main chemical components of Pomegranate peels and seeds, and the antioxidant activity of Pomegranate peels and seeds have been verified. Here we investigated whether the extracts of pomegranate peels (EPP) and seeds (EPS) have preventive efficacy on liver fibrosis induced by carbon tetrachloride (CCl4) in rats and explored its possible mechanisms. METHODS: The animal model was established by injection with 50 % CCl4 subcutaneously in male wistar rats twice a week for four weeks. Meanwhile, EPP and EPS were administered orally every day for 4 weeks, respectively. The protective effects of EPP and EPS on biochemical metabolic parameters, liver function, oxidative markers, activities of antioxidant enzymes and liver fibrosis were determined in CCl4-induced liver toxicity in rats. RESULTS: Compared with the sham group, the liver function was worse in CCl4 group, manifested as increased levels of serum alanine aminotransferase, aspartate aminotransferase and total bilirubin. EPP and EPS treatment significantly ameliorated these effects of CCl4. EPP and EPS attenuated CCl4-induced increase in the levels of TGF-ß1, hydroxyproline, hyaluronic acid laminin and procollagen type III. They also restored the decreased superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activities and inhibited the formation of lipid peroxidized products in rats treated with CCl4. CONCLUSION: The EPP and EPS have protective effects against liver fibrosis induced by CCl4, and its mechanisms might be associated with their antioxidant activity, the ability of decreasing the level of TGF-ß1 and inhibition of collagen synthesis.

Potential antiarrhythmic effect of methyl 3,4,5-trimethoxycinnamate, a bioactive substance from roots of polygalae radix: suppression of triggered activities in rabbit myocytes.

3,4,5-Trimethoxycinnamic acid (TMCA), methyl 3,4,5-trimethoxycinnamate (M-TMCA) and p-methoxycinnamic acid (PMCA) have been identified as the major bioactive components in the serum collected from rats treated with oral administration of Polygalae Radix ("YuanZhi," the roots of Polygala tenuifolia WILLD.), a traditional Chinese medicine used to relieve insomnia, anxiety and heart palpitation. The present study was designed to investigate its direct electrophysiological effects on isolated ventricular myocytes from rabbits. Whole-cell configuration of the patch-clamp technique was used to measure action potential (AP) and membrane currents in single ventricular myocytes enzymatically isolated from adult rabbit hearts. Ca(2+) transients were recorded in myocytes loaded with the Ca(2+) indicator Fluo-4AM. Among three bioactive substances of Polygala metabolites, only M-TMCA (15-30 µM) significantly shortened action potential duration at 50% and 90% repolarization (APD(50) and APD(90)) in cardiomyocytes in a concentration-dependent and a reversible manner. M-TMCA also inhibited L-type calcium current (I(Ca,L)), but showed effect on neither transient outward potassium current (I(to)) nor steady-state potassium current (I(K,SS)). Furthermore, M-TMCA abolished isoprenaline plus BayK8644-induced early afterdepolarizations (EADs) and suppressed delayed afterdepolarizations (DADs) and triggered activities (TAs). This potential anti-arrhythmic effects were likely attributed by the inhibition of I(Ca,L) and the suppression of intracellular Ca(2+) transients, which consequently suppress the generation of transient inward current (I(ti)). These findings suggest that M-TMCA may protect the heart from arrhythmias via its inhibitory effect on calcium channel.

Inhibition of cyclooxygenase-2 reduces hypothalamic excitation in rats with adriamycin-induced heart failure.

BACKGROUND: The paraventricular nucleus (PVN) of the hypothalamus plays an important role in the progression of heart failure (HF). We investigated whether cyclooxygenase-2 (COX-2) inhibition in the PVN attenuates the activities of sympathetic nervous system (SNS) and renin-angiotensin system (RAS) in rats with adriamycin-induced heart failure. METHODOLOGY/PRINCIPAL FINDING: Heart failure was induced by intraperitoneal injection of adriamycin over a period of 2 weeks (cumulative dose of 15 mg/kg). On day 19, rats received intragastric administration daily with either COX-2 inhibitor celecoxib (CLB) or normal saline. Treatment with CLB reduced mortality and attenuated both myocardial atrophy and pulmonary congestion in HF rats. Compared with the HF rats, ventricle to body weight (VW/BW) and lung to body weight (LW/BW) ratios, heart rate (HR), left ventricular end-diastolic pressure (LVEDP), left ventricular peak systolic pressure (LVPSP) and maximum rate of change in left ventricular pressure (LV±dp/dtmax) were improved in HF+CLB rats. Angiotensin II (ANG II), norepinephrine (NE), COX-2 and glutamate (Glu) in the PVN were increased in HF rats. HF rats had higher levels of ANG II and NE in plasma, higher level of ANG II in myocardium, and lower levels of ANP in plasma and myocardium. Treatment with CLB attenuated these HF-induced changes. HF rats had more COX-2-positive neurons and more corticotropin releasing hormone (CRH) positive neurons in the PVN than did control rats. Treatment with CLB decreased COX-2-positive neurons and CRH positive neurons in the PVN of HF rats. CONCLUSIONS: These results suggest that PVN COX-2 may be an intermediary step for PVN neuronal activation and excitatory neurotransmitter release, which further contributes to sympathoexcitation and RAS activation in adriamycin-induced heart failure. Treatment with COX-2 inhibitor attenuates sympathoexcitation and RAS activation in adriamycin-induced heart failure.

Adenine sulfate improves cardiac function and the cardiac cholinergic system after myocardial infarction in rats.

Recent studies have shown that vagal activation may have an important therapeutic implication for myocardial infarction (MI), but effective strategies remain unexplored. Here, we investigate whether adenine sulfate can preserve cardiac function and the cholinergic system against MI. Rats were treated with adenine sulfate for three weeks after coronary ligation. Cardiac function was assessed by hemodynamics. The muscarinic M(2) receptor and cholinesterase-positive nerves were semi-quantified by immunochemical and histochemical staining. The maximal binding capacity (B(max)) of muscarinic receptors, determined by radioligand binding assay, showed that cardiac function was impaired in MI rats. Adenine sulfate reversed MI-induced reduction of mean artery pressure and left ventricular systolic pressure and elevation of left ventricular end-diastolic pressure. Moreover, adenine sulfate also increased nitric oxide (NO) and nitric oxide synthase (NOS) activity. The amelioration was accompanied by a reversal of the infarction-induced reduction of cholinesterase-positive nerves and M(2)-receptor expression and B(max) in the adenine sulfate high dose group. Meanwhile, adenine sulfate treatment corrected the disorder of cardiac redox state by reduction in maleic dialdehyde and increase in superoxide dismutase. In conclusion, adenine sulfate exerts cardioprotection against MI and ameliorates NO production. Changes in cardiac vagal distribution density and M(2)-receptor expression raise the possibility that improvement of the cardiac cholinergic system is involved in adenine sulfate-induced cardioprotective effects.

Dehydroepiandrosterone-induced proliferation of prostatic epithelial cell is mediated by NFKB via PI3K/AKT signaling pathway.

Dehydroepiandrosterone (DHEA) is an endogenous steroid that is metabolized to androgens and/or estrogens in the human prostate. DHEA levels decline with age, and use of DHEA supplements to retard the aging process is of unproved effectiveness and safety. In this study, rat ventral prostatic epithelial cells were used to determine whether DHEA-modulated proliferation and prostate-specific antigen (PSA listed as KLKB1 in the MGI Database) production were mediated via the androgen receptor (AR) and its potential mechanism. We demonstrated that proliferation of prostatic epithelial cells and increase of PSA expression induced by DHEA were neutralized by Casodex or Ar siRNA, two specific AR blockers. DHEA stimulated Nfkb DNA binding activity, with this effect being blunted by Casodex or Ar siRNA. Moreover, the inhibition of the phosphatidylinositol 3-kinase (PI3K)/AKT nullified the effects of DHEA on NFKB activation. These findings suggested that DHEA stimulated normal prostatic epithelial cell proliferation, and AR is involved in DHEA-induced PSA expression in normal prostatic epithelial cells. This stimulation effect induced by DHEA is mediated by the activation of NFKB via PI3K/AKT pathway.

[Effect of isopropyl 3-(3,4-dihydroxyphenyl) -2-hydroxypropanoate on rat pulmonary artery smooth muscle].

OBJECTIVE: To investigate the effect of isopropyl 3-(3,4-dihydroxyphenyl)-2- hydroxypropanoate on vascular smooth muscle. METHOD: Isolated rat pulmonary artery was perfused and the tension of the vessel was measured, the effect of isopropyl 3-(3, 4-dihydroxyphenyl)-2-hydroxypropanoate on the pulmonary artery precontracted by noradrenaline (NE) and concentration-response curves of 5-hydroxytryptamine (5-HT), endothelin-1 (ET-1), U46619 and KCl was also observed. RESULT: Isopropyl 3-(3,4-dihydroxyphenyl) -2-hydroxypropanoate exerted relaxation effect on the endothelium-intact artery precontracted by NE in a concentration-dependent manner, which was inhibited with denuded endothelium. The right-shift of the concentration-response curves of 5-HT, ET-1, U46619 and KCl. CONCLUSION: Isopropyl 3-(3,4-dihydroxyphenyl)-2-hydroxypropanoate have relaxation action on rat pulmonary artery in the way of endothelium-dependance, the mechanism of relaxation action by isopropyl 3-(3,4-dihydroxyphenyl) -2-hydroxypropanoate may be related to calcium channels.