Saiko-ka-Ryukotsu-Borei-To inhibits intimal thickening in carotid artery after balloon endothelial denudation in cholesterol-fed rats

A Comorbid Rat Model of Neuroendocrine-Immune System Alterations Under the Impact of Risk Factors for Stroke

Hypercholesterolemia and carotid atherosclerosis contribute to the etiology of stroke. However, there has been a lack of appropriate comorbid animal models incorporating some of the ubiquitous characteristics that precede strokes. Curcumin is a natural active polyphenolic compound extracted from the rhizoma of Curcuma longa L. which possesses comprehensive bioactivities. The present study aimed to evaluate whether neurobehavioral deficits, neuroendocrine-immune dysregulations and cerebral microcirculation dysfunction, are part of the initial stages of cerebral ischemia in individuals suffering from carotid atherosclerosis resulting from a high cholesterol diet (HCD) and if they could be tested using a comorbid animal model. Furthermore, the utility of this model will be examined following the administration of curcumin. Adult wild-type SD rats were fed a regular diet or HCD and supplemented with either vehicle or curcumin for 4 weeks. Carotid injury was induced by an air-drying endothelial denudation method at the end of the second week. Plasma cholesterol, carotid pathomorphology, neurobehavioral tests, and neuroendocrine-immune parameters were measured. We found higher plasma levels of total cholesterol (TC), triglyceride (TG), low-density lipoprotein-cholesterol (LDL-C), intima and media (I/M) ratio, but lower high-density lipoprotein-cholesterol (HDL-C), spatial learning and memory capacity impairment, elevated NPY expression in the hypothalamus, increased plasma concentration of leptin, upregulated TNF-α, IL-1β, and CRP in the circulation as well as TNF-α and IL-1β in the cerebral cortex, plus enhanced ICAM-1, VCAM-1, and E-selectin in cerebral microvessels in HCD-fed model rats. All these alterations were ameliorated by curcumin. These results suggest that a comorbid rat model was effectively developed by HCD and carotid injury.

Impact of carotid atherosclerosis combined with hypercholesterolemia on cerebral microvessels and brain parenchyma in a new complex rat model

Most previous investigations about stroke caused by carotid atherosclerosis have focused on thromboembolism. There is a lack of knowledge about pathophysiology of the brain before ischemic insults. The objective of this study was to develop a new model of hypercholesterolemia plus carotid injury and to investigate the impact of carotid atherosclerosis combined with hypercholesterolemia in the rat brain. The complex rat model was developed by carotid injury induced by an air-drying endothelial denudation method after high cholesterol diet for 2 weeks. Plasma cholesterol, carotid pathomorphology, oxidative stress and inflammation in cerebral microvessels and brain parenchyma were measured at 7, 14 and 28 days after carotid surgery. The results showed that plasma concentrations of total cholesterol and low density lipoprotein-cholesterol were significantly increased, and severe carotid atherosclerosis and stenosis was observed in the complex rat model at 14 and 28 days after carotid surgery. The activity of superoxide dismutase was decreased, while the content of malondialdehyde was increased in cerebral microvessels and brain parenchyma. The levels of tumor necrosis factor-α and interleukin-1β were elevated in brain tissues of this model. Almost all above changes were more severe than those in either hypercholesterolemia alone group or carotid injury alone group. These results suggest that this complex rat model may more resemble human disease than the classic acute ischemic insult model for assessing the impact of carotid atherosclerosis as a preexisting disease on cerebral microcirculation and brain tissue.

Inhibitory Effects of Bezoar Bovis on Intimal Formation and Vascular Smooth Muscle Cell Proliferation in Rat

Intimal formation of animal carotid arteries induced by balloon endothelial denudation has been considered to be an "accelerated atherosclerosis" model and used in primary screening methods to evaluate natural drugs and chemical candidates. The aim of the present study was to examine whether intimal formation is prevented by Bezoar Bovis (dried cattle gallbladder stones: Niuhuang in Chinese and Go-o in Japanese), which has been used to prevent heart palpitation in patients with hypertension. The intimal-to-medial area ratio in rat carotid arteries 7 days after balloon endothelial denudation was significantly reduced by oral administration of Bezoar Bovis. Bezoar Bovis also suppressed vascular smooth muscle cells (VSMCs) proliferation, which is thought to play important roles in the intimal formation after endothelial damage and also atherosclerosis resulting from long-term inappropriate lifestyle. The present findings suggest that Bezoar Bovis may be useful for preventing atherosclerosis and for protection against restenosis after percutaneous coronary intervention, for which effective reduction method is not currently available.

Herbal remedies supply a novel prospect for the treatment of atherosclerosis: a review of current mechanism studies

Atherosclerosis (AS) is a systemic cardiovascular disease with complicated pathogenesis involving oxidative stress, endothelial dysfunction and chronic inflammation. Increasing lines of evidence have questioned the statins-dominated treatment for AS, including their dangerous side-effects such as the breakdown of muscle when taken in larger doses. A multifaceted approach that addresses all major risk factors or pathological targets may provide an ideal treatment for AS. Studies of the herbal remedies on the prevention and treatment of AS have received much attention in recent years. This review summarizes some important experimental findings regarding their mechanisms of action on AS. Using the pre-set PUBMED searching syntax and inclusion criteria, representative citations published in English concerning the experimental studies of 14 herbal materials were included. We found that many extracts and (or) single compounds from these herbal materials, such as Salvia miltiorrhiza, Curcuma longa, Rheum undulatum and Panax notoginseng, could regulate multiple key targets involved in the initiation and propagation of AS. Some important findings about the effects of herbal formulations on AS were also reviewed. Given the complicated nature of AS and the holistic, combinational approach of herbal remedies, we propose that mixed herbal preparations with multiple active ingredients may be preferable for the prevention and treatment of AS. Further rigorously designed pharmacological evaluation and multi-centred clinical trials are warranted.

The fixed herbal drug composition "Saikokaryukotsuboreito" prevents bone loss with an association of serum IL-6 reductions in ovariectomized mice model

PURPOSE

Saikokaryukotsuboreito (SRB) is a traditional Japanese herbal medicine that has been used to treat hyperlipidemia. As some studies have shown that lipid-lowering drugs reduce osteoporosis, we investigated the effect of SRB on bone metabolism in the postmenopausal period using an ovariectomized (OVX) murine model.

MATERIAL AND METHODS

Fifteen aged 9 weeks female mice were divided into three groups (n=5 each). The OVX group and SRB group underwent bilateral ovariectomy, after which the OVX group was fed a normal diet and the SRB group fed a normal diet containing 2% SRB. The sham group underwent sham surgery and was then fed a normal diet. Eight weeks after surgery, all mice were sacrificed, and bone volume, bone histomorphometric parameters, and bone-associated phenotype were compared among the groups.

RESULTS

Compared with the OVX group, the SRB group showed suppression of bone volume loss at the tibia (SRB group: 12.7+/-0.7%, OVX group: 9.8+/-0.4%; p=0.005, ANOVA) and lumbar spine (SRB group: 15.1+/-0.9%, OVX group: 11.3+/-0.1%; p=0.031, ANOVA). A significant decrease in eroded surface was also observed in SRB-treated ovariectomized mice compared with the OVX group (p=0.022, ANOVA). We also found that serum levels of interleukin (IL)-6, a primary mediator of bone resorption, in the SRB group were significantly lower than in the OVX group (SRB: 52.5+/-6.8pg/ml; OVX: 138.0+/-23.1pg/ml; p=0.011, ANOVA). However, unexpectedly, SRB did not affect estradiol and total cholesterol in ovariectomized mice.

CONCLUSION

SRB can prevent loss of bone volume and suppress serum IL-6 levels in this postmenopausal model and is a promising candidate for treatment of postmenopausal osteoporosis.

Bofutsushosan, a traditional Chinese formulation, prevents intimal thickening and vascular smooth muscle cell proliferation induced by balloon endothelial denudation in rats

Bofutsushosan (BOF), a traditional Chinese formulation (Kampo formulation in Japanese), is widely used for patients with obesity and hyperlipidemia resulting from long-term inappropriate lifestyles. Since atherosclerosis, a lifestyle-related disease, is accompanied by an abnormal accumulation of vascular smooth muscle cells (VSMCs) in the intimal area of the artery, we investigated the preventive effect of BOF on intimal thickening. Oral administration of BOF extracts 3 d before and 7 d after balloon endothelial denudation dose dependently suppressed the intimal thickening and proliferation of VSMCs in the intimal area in rat carotid arteries. This model has a similar pathologic process to atherosclerosis and is considered to be an "accelerated atherosclerosis" model. BOF extract also dose dependently inhibited the migration of cultured VSMCs. BOF extract suppressed serum lipid levels, which are a major risk factor for atherosclerosis. These findings clarified the usefulness of BOF in cardiovascular risk-reduction therapy.

Inhibition of vascular smooth muscle cell migration by serum from rats treated orally with Saiko-ka-Ryukotsu-Borei-To, a traditional Chinese formulation

Oral administration of Saiko-ka-Ryukotsu-Borei-To (SRB), a traditional Chinese formulation, has been found to prevent intimal thickening of the carotid artery after balloon endothelial denudation in cholesterol-fed rats. To clarify the mechanism of this effect, the present study investigated if SRB inhibits vascular smooth muscle cell (VSMC) migration, which plays an important role in the development of intimal thickening after endothelial injury. The serum (SRB serum) sampled from cholesterol-fed rats treated orally with SRB for 3 days before and 4 days after the injury dose-dependently inhibited the migration of cultured VSMCs. When added directly to cultured VSMCs, the SRB extract did not inhibit VSMC migration. It is remarkable that SRB serum, which may contain a much lower concentration of SRB ingredients compared with the SRB extract, inhibited cultured VSMC migration. The present testing system using serum obtained from animals treated orally with traditional Chinese formulations may be useful for clarifying the pharmacological efficacy of such drugs, including many non-absorbable components. Furthermore, it may be useful in the search for new active compounds in serum after oral administration of traditional Chinese formulations, the active metabolites of which have not been identified.