Protective effect of pitavastatin,a 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor,on ischemia-induced neuronal damage

Abstract

We investigated the neuroprotective effects of a novel 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor (pitavastatin) on ischemic neuronal damage in gerbils using immunohistochemistry. The animals were allowed to survive for 14 days after 5 min of ischemia induced by bilateral occlusion of the common carotid arteries. Five days after ischemia, severe neuronal cell loss was observed in the hippocampal CA1 sector. Prophylactic treatment with pitavastatin dose-dependently prevented the hippocampal CA1 neuronal cell loss 5 days after ischemia. Immunohistochemical study did not show the change of nNOS and iNOS expression in the hippocampus except for, in a few regions, up to 1 day after ischemia. Thereafter, the expression of iNOS was observed in the hippocampal CA1 sector 5 and 14 days after ischemia. In contrast, the expression of nNOS and eNOS gradually decreased in the hippocampal CA1 sector up to 14 days after ischemia. Prophylactic treatment with pitavastatin also prevented the expression of iNOS and the decrease of eNOS expression and the number of nNOS-positive cells in the hippocampal CA1 sector 5 days after ischemia. However, prophylactic treatment with pitavastatin at a dose of 10 mg kg^-1 did not change the immunoreactivity of iNOS and nNOS in the hippocampus at an early phase after ischemia. In contrast, this drug prevented the reduction of eNOS immunoreactivity in the hippocampal CA1 neurons at an early phase after ischemia. These findings demonstrate that the HMG-CoA reductase inhibitor pitavastatin can protect hippocampal CA1 neurons after transient forebrain ischemia through up-regulation of eNOS expression in this region. Thus pharmacological modulation of eNOS expression may offer a novel therapeutic strategy for cerebral ischemic stroke.     

蒙药材瑞香狼毒体外细胞毒性的研究

目的研究蒙药瑞香狼毒炮制前后的体外细胞毒性和抗肿瘤活性。方法利用石油醚、醋酸乙酯和正丁醇分别萃取获得瑞香狼毒药材生品、奶制品、煎膏制品的各溶剂提取物,再通过萃取、分离纯化方法分别获得瑞香狼毒的9个单体化合物、总蛋白质和6个相对分子质量不同的蛋白质组分(Pr.1~Pr.6)。将各溶剂提取物及单体化合物制成浓度为2.0mg/ml的溶液,总蛋白质制成浓度分别为0.5、1.0、2.0、4.0、6.0、8.0mg/ml的系列溶液,各蛋白质组分制备成浓度均为10mg/ml的溶液,分别作为样品溶液,采用MTT法分别测定各样品对人肝癌SMMC-7721细胞、狗肾MDCK细胞的生长抑制作用。结果瑞香狼毒总蛋白质抗肿瘤活性和细胞毒性作用随其浓度增加而增强,其中4个蛋白质组分呈现较强的抗肿瘤活性,其活性由强至弱依次为Pr.4≥Pr.6≥Pr.3=Pr.2,3个蛋白质组分具有细胞毒性,其毒性由强至弱依次为Pr.4≥Pr.3≥Pr.1。瑞香狼毒单体化合物中,西瑞香素、狼毒色原酮、异狼毒素呈现不同程度的抗肿瘤活性,而狼毒色原酮、异狼毒素同时具有较弱的细胞毒性。除石油醚和多糖提取物外,瑞香狼毒药材生品各溶剂提取物均呈现不同程度的抗肿瘤活性和细胞毒性,并呈药物剂量依赖性;而炮制后,在保留一定程度抗肿瘤活性的基础上,其相应各溶剂提取物的细胞毒性均降低。结论瑞香狼毒的细胞毒性主要源自多成分的协同作用,其蛋白质可能是瑞香狼毒的主要毒性位点之一,而炮制方法可降低瑞香狼毒药材的毒性且保留其生物活性。     

Autoradiographic and confocal laser microscopic observation show lafutidine binds to CGRP-immunoreactive nerves as well as gastric parietal cells

The present study was undertaken to observe the binding sites of lafutidine, a newly invented H₂ receptor antagonist ((+/-)-2-(furfurylsulfinyl)-N-[4-[4-(piperidinomethyl)-2-pyridyl]oxy-(Z)-2 butenyl] acetamide), in the Mongolian gerbil and human gastric mucosa using unfixed cryostat section or incubation with aqueous solution of tritiated lafutidine, followed by in vitro autoradiography or autoradiography of soluble compounds. The localization of calcitonin gene-related peptide immunoreactivity was compared with the lafutidine binding sites. As a result, lafutidine-specific binding sites in the body of the fundic glands were accumulated on the parietal cells, while in the neck and base of the fundic glands, lafutidine was found to bind to the CGRP immunoreactive nerves. In the human fundic mucosa, the lafutidine bindings were also observed on the enteric nerves as well as the parietal cells. In conclusion, autoradiographic studies have shown that lafutidine effector sites coincided with the CGRP-immunoreactive nerves as well as the parietal cells.     

Healing of Helicobacter pylori -Induced Gastric Ulcers in Mongolian Gerbils (Combined Treatment with Omeprazole and Clarithromycin)

Helicobacter pylori can colonize the stomachs ofMongolian gerbils and subsequently induce penetratingulcers five months later. Using this gerbil model, theeffects of both combined treatment with omeprazole and clarithromycin, as well as treatment witheach drug separately, on the healing of H.pylori-induced gastric ulcers, and the effects of thecessation of the drug treatment on healed ulcers wereexamined. Beginning five months after H. pylori(NCTC11637) inoculation, omeprazole (four weeks),clarithromycin (two weeks), their combination, or thevehicle was orally administered once daily. These drugs,in combination or separately, markedly enhancedulcer healing and lowered the increased myeloperoxidase(MPO) activity. While omeprazole had no effect on viableH. pylori, clarithromycin and the drug combination significantly reduced viable H. pylori. Thedegree of bacterial eradication was much higher in thecase of the drug combination compared to clarithromycinalone. Four months after cessation of the treatment, visible ulcers, hypertrophic gastritis andincreased MPO activity were found in the control animals(all H. pylori-positive). Nonetheless, only one of theeight gerbils subjected to the drug combination developed a small ulcer, although nohypertrophic gastritis was exhibited. It is concludedthat: (1) the gerbil model of H. pylori infection isuseful for the study of ulcer healing; (2) combinedtreatment with omeprazole and clarithromycin enhances theulcer healing in infected gerbils; and (3) healed ulcersdo not relapse, despite cessation of the drugtreatment.     

Pathological Changes in the Formation of Helicobacter pylori-Induced Gastric Lesions in Mongolian Gerbils

We examined pathological changes in theformation of Helicobacter pylori-induced gastric lesionsin Mongorian gerbils. H. pylori (NCTC11637) was orallyadministered once to the animals and was detected in the gastric mucosa of all gerbils given thebacteria. The number of viable H. pylori increasedduring the initial two weeks and thereafter reached aplateau level. The initial pathological changes were found at one week, ie, edema/congestion and awhite viscous substance only in the antrum. At twoweeks, superficial damage appeared in the antrum,although inflammatory cell infiltration had notoccurred. Gastritis with lymphoid follicles was observedin the antrum and fundus from three weeks. At fourweeks, mucosal lesions were detected as a fewhemorrhagic spots in the fundus adjacent to the antrum.In the control animals, however, no pathologicalchanges were observed even at four weeks. In the gastricmucosa infected with H. pylori , myeloperoxidaseactivity was negligible at two weeks, but was extremely elevated at four weeks. Similarly, neutrophilchemotactic activity was only slightly increased at twoweeks, but was markedly elevated at four weeks. Theseresults indicate that H. pylori infection induces initial pathological changes only in theantrum, but mucosal lesions occur in the fundus adjacentto the antrum. Furthermore, it is demonstrated that theinitial superficial damage is generated by factors other than chemokines and neutrophil-associatedfactors, although mucosal inflammation may contribute tothe subsequent formation of lesions andulcers.     

补阳还五汤和黄芪对脑缺血再灌注后星形胶质细胞的影响

[目的]为了探讨补阳还五汤和黄芪对脑缺血再灌注后星形胶质细胞（AS）的影响。[方法]采用沙土鼠双侧颈动脉夹闭脑缺血模型。于脑缺血15min再灌注24h和48h后运用免疫组织化学技术观察星型胶质纤维酸性蛋白（GFAP）的动态表达。[结果]缺血15min再灌注24h后，GFAP免疫阳性反应达高峰，补阳还五汤和黄芪可使GFAP免疫反应减轻；缺血15min再灌注48h后GFAP表达减弱，补阳还五汤和黄芪可使其增强。[结论]补阳还五汤和黄芪对脑缺血再灌注后星形胶质细胞的调节作用可能与脑缺血损伤后神经功能的恢复有关。