timosaponin-b-ii and Disease-Models--Animal

The aim of the present study was to investigate the cardioprotective effects of Timosaponin B II (TB), a main bioactive constituent from Anemarrhenae asphodeloides Bge, on an isoproterenol (ISO)-induced myocardial infarction model in rats and explore its underlying mechanisms. Rats were treated with TB (50 mg/kg, 100 mg/kg) or diltiazem hydrochloride (DH, 5 mg/kg) by gastric gavage for five days. At the 4th and 5th days, myocardial injury was induced by ISO injection (85 mg/kg) at an interval of 24 h for 2 consecutive days. After the induction, rats were anaesthetized with pentobarbital sodium (30 mg/kg) to record the electrocardiogram. Our research showed that ISO administration resulted in significant elevations in the ST-segment, the levels of cardiac injury biomarkers creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH), and concentrations of serum proinflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). Pretreatment with TB significantly reversed these alterations induced by ISO challenge. The cardioprotective effects of TB were further proved by the histopathological examination. Exploration of the underlying mechanisms of its actions revealed that TB pretreatment restored the ISO-induced decrease of super oxide dismutase (SOD) and the increase of malondialdehyde (MDA). Meanwhile, we found that the enhancement of antioxidant defense system might be associated with the increased heme oxygenase isoform 1 (HO-1) induction and activated nuclear respiratory factor 2 (Nrf-2) translocation. Furthermore, the present research also demonstrated that nuclear translocation of Nrf-2 and subsequent HO-1 expression might be associated with nuclear factor kappa B (NF-κB) pathway activation. Taken together, our finding demonstrated that TB might have a potential benefit in preventing ischemic heart diseases like myocardial infarction.

Topics: Anemarrhena; Animals; Biomarkers; Blotting, Western; Cardiotonic Agents; Disease Models, Animal; Isoproterenol; Male; Myocardial Infarction; Rats; Saponins; Steroids

Our previous studies indicated that oxidative stress up-regulated the expression of β-amyloid precursor protein cleavage enzyme-1 (BACE1) in rat retina. Pharmacological reports have shown Timosaponin-BII, a purified extract originating from Chinese medical herb Rhizoma Anemarrhenae, is characterized as an antioxidant. Our present study aimed to determine whether Timosaponin-BII affected the expression of BACE1, β-amyloid precursor protein cleavage production of Aβ1-40 and β-C-terminal fragment (β-CTF) in rat retina, which were pre-treated with the oxidizing agent (solution of FeCl₃).. Few distinctions of BACE1 distribution were observed among all groups (normal control group, model group, Timosaponin-BII treated and vehicle control groups). Rat retinas in model group and vehicle control group manifested an apparent up-regulation of BACE1 expression. Meanwhile, the level of malonaldehyde (MDA), Aβ1-40 and β-CTF were increased. However, when comparing with the vehicle control group, the retinas in Timosaponin-BII treated group showed significantly less BACE1 (p<0.05) and accumulated less Aβ1-40 or β-CTF (p<0.05). It also showed significantly decreased level of MDA (p<0.05) and prolonged partial thromboplastin time (p<0.05).. Our data suggested that Timosaponin-BII remarkably inhibited the up-regulation of BACE1 and reduced the over-production of β-CTF and Aβ in rat retina, which was induced by FeCl₃. The mechanism of Timosaponin-BII on BACE1 expression may be related to its antioxidant property.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid Precursor Protein Secretases; Anemarrhena; Animals; Antioxidants; Chlorides; Disease Models, Animal; Drugs, Chinese Herbal; Ferric Compounds; Male; Malondialdehyde; Oxidative Stress; Partial Thromboplastin Time; Phytotherapy; Rats; Rats, Sprague-Dawley; Retina; Rhizome; Saponins; Steroids; Up-Regulation

Sapogenins from Anemarrhenae asphodeloides was reported to improve the learning and memory abilities. In this study, we investigated the effect of Timosaponin B-II(TB-II), a purified extract from A. asphodeloidesb on rat vascular dementia (VD) produced by transient (2h) middle cerebral artery occlusion. The learning and memory abilities of rats were measured by water maze task and passive avoidance task. Daily oral administration of TB-II at two different dose levels of 100 and 200 mg/kg resulted in a significant improvement of the deficit in the learning of the water maze task, beginning 14 days after ischemia. Shortened mean escape latency was detected in TB-II group compared with model group during the same trial days. TB-II treatment also significantly reversed the ischemia-induced retention deficit determined by a one trial step-down type of passive avoidance task. Meanwhile, the expression of interleukin-10, an anti-inflammatory cytokine, and its receptor were significantly increased in TB-II treated VD rats. The results presented the first evidence of a neuroprotective effect of TB-II in the model of vascular dementia. We suggest that the anti-dementia effect by TB-II is derived at least in part from its anti-inflammatory properties.

Topics: Animals; Behavior, Animal; Brain Ischemia; Disease Models, Animal; Dose-Response Relationship, Drug; Escape Reaction; Gene Expression Regulation; Interleukin-10; Learning Disabilities; Male; Maze Learning; Memory Disorders; Rats; Rats, Sprague-Dawley; Reaction Time; Saponins; Steroids