Effect and possible mechanisms of dioscin on ameliorating metabolic glycolipid metabolic disorder in type-2-diabetes.

BACKGROUND: Our previous study revealed that microRNA-125a-5p plays a crucial role in regulating hepatic glycolipid metabolism by targeting STAT3 in type 2 diabetes mellitus (T2DM). Dioscin, a major active ingredient in Dioscoreae nipponicae rhizomes, displays various pharmacological activities, but its role in T2DM has not been reported. PURPOSE: The aim of this study was to investigate the effect of dioscin on T2DM and elucidate its potential mechanism. METHODS: The effect of dioscin on glycolipid metabolic disorder in insulin-induced HepG2 cells, palmitic acid-induced AML12 cells, high-fat diet- and streptozotocin- induced T2DM rats, and spontaneous T2DM KK-Ay mice were evaluated. Then, the possible mechanisms of dioscin were comprehensively evaluated. RESULTS: Dioscin markedly alleviated the dysregulation of glycolipid metabolism in T2DM by reducing hyperglycemia and hyperlipidemia, improving insulin resistance, increasing hepatic glycogen content, and attenuating lipid accumulation. When the mechanism was investigated, dioscin was found to markedly elevate miR-125a-5p level and decrease STAT3 expression. Consequently, dioscin increased phosphorylation levels of STAT3, PI3K, AKT, GSK-3ß, and FoxO1 and decreased gene levels of PEPCK, G6Pase, SREBP-1c, FAS, ACC, and SCD1, leading to an increase in glycogen synthesis and a decrease in gluconeogenesis and lipogenesis. The effects of dioscin on regulating miR-125a-5p/STAT3 pathway were verified by miR-125a-5p overexpression and STAT3 overexpression. CONCLUSIONS: Dioscin showed potent anti-T2DM activity by improving the inhibitory effect of miR-125a-5p on STAT3 signaling to alleviate glycolipid metabolic disorder of T2DM.

[The roles of TSP-1 and its receptor CD47 in pathogenesis of paraquat-induced pulmonary fibrosis in rats].

Objective: To establish a rat model of paraquat (PQ) -induced pulmonary fibrosis and observe the changes in thrombospondin-1 (TSP-1) and its receptor CD47 in lung tissue, and to investigate their roles in the pathogenesis of PQ-induced pulmonary fibrosis. Methods: Fifty-four clean adult male Sprague-Dawley rats were randomly divided into normal control group (n=6) and 2 h, 12 h, 1 d, 3 d, 7 d, and 14 d PQ poisoning groups (n=8 per group). A rat model of PQ poisoning was established by a single gavage of 20 wt.% PQ solution (50 mg/kg). Flow cytometry was used to determine the concentration of reactive oxygen species (ROS) in blood and lung tissue. Enzyme-linked immunosorbent assay was used to determine the concentrations of hydroxyl radicals, malondialdehyde, and hydroxyproline in lung tissue. HE staining and Masson staining were used to observe the pathological damage of lung tissue after PQ poisoning. The expression of TSP-1 and CD47 in lung tissue was measured by Immunohistochemistry. Results: Compared with the normal control group, the 2 h to 7 d PQ poisoning groups showed significant increases in ROS fluorescence intensity in red blood cells and lung tissues and the concentrations of malondialdehyde and hydroxyl radicals in lung tissue (P<0.05) , and the 14 d PQ poisoning group had a significant increase in the concentration of hydroxyproline in lung tissue (P<0.05). HE staining showed that the 2 h to 7 d PQ poisoning groups had significantly higher semiquantitative pathological scores of pulmonary alveolitis than the normal control group (P<0.05). The Masson staining showed that the 7 d and 14 d PQ poisoning groups had significantly higher semiquantitative pathological scores of pulmonary fibrosis than the normal control group (P<0.05). Compared with the normal control group, all PQ poisoning groups (except the 12 h group) had significantly increased expression of TSP-1 in lung tissue (P<0.05) , and all PQ poisoning groups (except the 1 d group) had significantly increased expression of CD47 in lung tissue (P<0.05). Within 2 h after PQ poisoning, the expression of TSP-1 and CD47 was positively correlated with the concentrations of ROS, hydroxyl radicals, and malondialdehyde and the degree of pulmonary alveolitis (P<0.01) ; at 1 d after PQ poisoning, the expression of TSP-1 and CD47 was positively correlated with the concentration of hydroxyproline in lung tissue (P<0.01) . Conclusion: The expression of TSP-1 and CD47 is closely related to oxidative stress and subsequent pulmonary fibrosis, and they may be involved in the development and progression of pulmonary alveolitis and subsequent pulmonary fibrosis in rats with PQ poisoning.

Comparison of extracts from cooked and raw lentil in antagonizing angiotensin II-induced hypertension and cardiac hypertrophy.

AIM: The objective of this study is to examine effects of extracts from cooked lentils on angiotensin II (Ang II)-induced hypertension, cardiac hypertrophy and fibrosis in normotensive rats. MATERIALS AND METHODS: Animals were divided into four groups (n=5 each group): control group, Ang II group, Ang II plus cooked lentil extract (Ang II+CLE) group, and Ang II plus raw lentil extract (Ang II+RLE) group. The telemetry blood pressure transducers were implanted into all rats. A telemetry BP probe was positioned intra-abdominally and secured to the ventral abdominal muscle with the catheter inserted into the lower abdominal aorta. Heart wall thickness, cross-sectional area of cardiomyocytes, diameter of the arterial cross-sections, and perivascular fibrosis in heart and kidney were measured. The surface area of positive-staining cardiomyocytes was analyzed using image analysis software. Reactive oxygen species (ROS) generation was determined using an oxidant-sensitive fluorogenic probe. RESULTS: Rats that received cooked or raw lentil extracts (oral administration, 8 weeks) show significantly attenuated Ang II-induced elevation in blood pressure, cardiac hypertrophy, perivascular fibrosis. Results demonstrated that pretreatment of cardiomyocytes with cooked or raw lentil extract significantly attenuated the Ang II-induced increase in the size of cells (16.0±1.7% and 21.2±2.9%, respectively, n=5, p < 0.05), and cooked or raw lentil extracts also attenuated the Ang II-induced increase in the reactive oxygen species levels in cardiomyocytes (19.8±2.2% & 26.6±3.1%, respectively, n=5, p < 0.05). CONCLUSIONS: This study showed that extracts from cooked lentils could prevent Ang II-induced elevation in blood pressure, cardiac hypertrophy, small arterial remodeling and perivascular fibrosis, and heating process does not have any significant affect on these protective effects.

Isolation and identification of metabolites of osthole in rats.

Osthole (Ost), one of the major components of Cnidium monnieri (L.) Cusson, is had the structure of an isopentenoxy-coumarin with a range of pharmacological activities. In the present study, the metabolism of Ost in male Sprague-Dawley rats was investigated by identifying Ost metabolites excreted in rat urine. Following an oral dose of 40 mg/kg Ost, 10 phase I and 3 phase II metabolites were isolated from the urine of rats, and their structures identified on the basis of a range of spectroscopic data, including 2D-NMR techniques. These metabolites were fully characterized as 5'-hydroxyl-osthole (M-1), osthenol (M-2), 4'-hydroxyl-osthole (M-3), 3, 5'-dihydroxyl-osthole (M-4), 5'-hydroxyl-osthenol (M-5), 4'-hydroxyl-2', 3'-dihydro-osthenol (M-6), 4'-hydroxyl-osthenol (M-7), 3, 4'-dihydroxyl-osthole (M-8), 2', 3'-dihydroxyl-osthole (M-9), 5'-hydroxyl-2', 3'-dihydroosthole (M-10), osthenol-7-O-ß-D-glucuronide (M-11), osthole-4'-O-ß-D-glucuronide (M-12) and osthole-5'-O-ß-D-glycuronate (M-13). This is the first identification of M-1, M-3 to M-13 in vivo. On the basis of the metabolites profile, a possible metabolic pathway for Ost metabolism in rats has been proposed. This is the first systematic study on the phases I and II metabolites of 8-isopentenoxy-coumarin derivative.

Identification of cinobufagin metabolites in the bile of rats.

Cinobufagin (1) is a major bufadienolide in ChanSu (a traditional Chinese medicine) with a wide range of pharmacological activities. In this paper, the in vivo metabolites of 1 in rats were studied. Nine metabolites were isolated from the bile of rats, and their structures were identified as: desacetylcinobufagin (2), 3-ketodesacetylcinobufagin (3), 3-epi-desacetylcinobufagin (4); 5beta-hydroxy-3-epi-desacetylcinobufagin (5), 1alpha-hydroxy-3-epi-desacetylcinobufagin (6), 12beta-hydroxy-3-epi-desacetylcinobufagin (7), 1beta-hydroxy-3-epi-desacetylcinobufagin (8), 1alpha,5alpha-dihydroxy-3-epi-desacetylcino-bufagin (9), and 2alpha, 5beta-dihydroxy-3-epi-desacetylcinobufagin (10), respectively, on the basis of widely spectroscopic studies including two-dimensional-nuclear magnetic resonance (NMR). Among them, metabolites 6-10 are new compounds. The results show that hydroxylation is the main reaction involved in metabolism of 1, and the preferred hydroxylation sites were C-1 and C-5.

Inhibition of nicotine-DNA adduct formation in mice by six dietary constituents.

Nicotine [3-(1-methyl-2-pyrrolidinyl)-pyridine] is a major alkaloid in tobacco products and has proven to be a potential genotoxic compound. Many natural dietary products can suppress the DNA adduction, and hence act as inhibitors of cancer. In this study, we investigated the inhibitory effects of curcumin, garlic squeeze, grapeseed extract, tea polyphenols, vitamin C, and vitamin E on nicotine-DNA adduction in vivo using an ultrasensitive method of accelerator mass spectrometry (AMS). The results demonstrated that all the dietary constituents induced marked dose-dependent decrease in nicotine-DNA adducts as compared with the control. The reduction rate reached about 50% for all agents, except garlic squeeze (40%), even at its highest dose level. Amongst the six agents, grapeseed extract exhibited the strongest inhibition to the DNA adduct formation. Therefore, we may arrive at a point that these dietary constituents are beneficial to prevent the harmful adduct formation, and thus to block the potential carcinogenesis induced by nicotine.

[Effect of acupuncture on heart rate variability in coronary heart disease patients].

The heart rate variability (HRV) of 20 coronary heart disease patients has been determined before and after acupuncture treatment by using frequency domain analysis of HRV. The results showed that there was significant difference between the change of low frequency (LF) components in HRV before and after manipulatory acupuncturing Neiguan group and electro-acupuncturing Neiguan group (P < 0.05), while there was no significant difference in the control group (P > 0.05), also no significant difference on the change of high frequency (HF) components in HRV before and after acupuncture in both groups. In the electro-puncturing group, the LF/HF change was marked (P < 0.05). And in manipulatory acupuncturing group, the value of LF reduced to the lowest level 10 minutes after acupuncture treatment, and then gradually restored 20 to 30 minutes later, without any rebound phenomenon. It suggested that acupuncture could regulate and improve HRV in coronary heart disease patients. Its mechanism might be relevant to the central regulation and neurotransmitter participation.