Dual effects of silibinin treatment on autophagy-regulated dermal apoptosis retardation and epidermal apoptosis up-regulation in UVB-induced skin inflammation

Skin inflammation induced by ultraviolet B (UVB) radiation is characterized by migration and chemotaxis of inflammatory cells, epidermic thickening and erythema. Apoptosis and autophagy of epidermal and dermal cells are involved in its development through the adjustment of balance between cell survival and death. In this study, the role of balance between cell survival and apoptosis in dermis and epidermis in UVB-induced skin inflammation and the effect of autophagy on the balance were elucidated, and the protective mechanism of silibinin was investigated through the examination of the influence of autophagy activation or inhibition on erythema, migration, and chemotaxis of inflammatory cells as well as apoptosis adjustments. In UVB-irradiated controls, dermal apoptosis was retarded and the survival of inflammatory cells was promoted through the up-regulation of dermal autophagic level; epidermal apoptosis was increased through the down-regulation of epidermal autophagic level, causing migration and chemotaxis of neutrophils and mast cells as well as skin erythema. In silibinin-treated group (50 mg/kg/day for 4 days), dermal apoptosis was increased through inhibiting dermal autophagy; improper adjustment of epidermal apoptosis was attenuated through promoting epidermal autophagy, presenting dual effects on the balance between autophagy and apoptosis of epidermal and dermal cells and the protection.     

Screening of herbal components for attenuating amiodarone-induced hepatotoxicity on gel-entrapped rat hepatocytes

Abstract

Amiodarone (AMD) is a hepatotoxic drug that has been widely used as a class III antiarrhythmic drug. Because, to date, only a few kinds of protectants are able to reduce AMD hepatotoxicity, this article utilized gel-entrapped rat hepatocytes to screen effective protectants from a series of herbal compounds for their effects against AMD-induced toxicity. Herbal compounds, including matrine, silibinin, glycyrrhizic acid, schisandrin B, epigallocatechin gallate and anisodamine, were cotreated with AMD to assess their protective effect, whereas vitamin E, which has been shown to be protective in rats, was selected as a control. It was found that vitamin E, as with its function in rats, provided the best protection in gel-entrapped rat hepatocytes, whereas silibinin, a major component of silymarin, could largely reduce AMD-induced hepatotoxicity, performing a similar function as silymarin in rats. The results illustrated that gel-entrapped hepatocytes may reflect the protective effects of drugs and serve as a reliable model for screening hepatoprotectants. Moreover, matrine, a widely used monomer of the traditional Chinese medicine, Sophora flavescens, for treatment of arrhythmia, was evidenced to show some effective protections against AMD hepatotoxicity. Taken together, gel-entrapped rat hepatocytes may provide a platform for screening effective candidates from the herbal component library.     

Silibinin’s regulation of proliferation and collagen gene expressions of rat pancreatic β-cells cultured on types I and V collagen involves β-catenin nuclear translocation

Extracellular matrix (ECM) molecules have multiple functions; prevention of cytotoxicity, provision of mechanical support, cell adhesive substrates and structural integrity in addition to mediation of cellular signaling. In this study, we report that the proliferation of INS-1 cells cultured on collagen I-coated dishes is enhanced, but it is inhibited on collagen V-coated dishes. Inhibitory proliferation on collagen V-coated is not due to apoptosis induction. Silibinin decreases hepatic glucose production and protects pancreatic β-cells, as a potential medicine for type II diabetes. Silibinin up-regulates the proliferation of cells cultured on both collagen I- and V-coated dishes. Collagen-coating regulates gene expression of collagen in a collagen type-related manner. Silibinin increases mRNA expression of collagen I in the cells on collagen I- and V-coated dishes; however, silibinin decreases collagen V mRNA expression on collagen I- and V-coated dishes. Collagen I-coating significantly enhances nuclear translocation of β-catenin, while collagen V-coating reduces it. Differential effects of silibinin on collagen I mRNA and collagen V mRNA can be accounted for by the finding that silibinin enhances nuclear translocation of β-catenin on both collagen I- and V-coated dishes, since phenomenologically nuclear translocation of β-catenin enhances collagen I mRNA but represses collagen V mRNA. These results demonstrate that nuclear translocation of β-catenin up-regulates proliferation and collagen I gene expression, whereas it down-regulates collagen V gene expression of INS-1 cells. Differential gene expressions of collagen I and V by nuclear β-catenin could be important for understanding fibrosis where collagen I and V may have differential effects.     

Treatment of Cyanobacterial (Microcystin) Toxicosis Using Oral Cholestyramine: Case Report of a Dog from Montana

A two and a half year old spayed female Miniature Australian Shepherd presented to a Montana veterinary clinic with acute onset of anorexia, vomiting and depression. Two days prior, the dog was exposed to an algal bloom in a community lake. Within h, the animal became lethargic and anorexic, and progressed to severe depression and vomiting. A complete blood count and serum chemistry panel suggested acute hepatitis, and a severe coagulopathy was noted clinically. Feces from the affected dog were positive for the cyanobacterial biotoxin, microcystin-LA (217 ppb). The dog was hospitalized for eight days. Supportive therapy consisted of fluids, mucosal protectants, vitamins, antibiotics, and nutritional supplements. On day five of hospitalization, a bile acid sequestrant, cholestyramine, was administered orally. Rapid clinical improvement was noted within 48 h of initiating oral cholestyramine therapy. At 17 days post-exposure the dog was clinically normal, and remained clinically normal at re-check, one year post-exposure. To our knowledge, this is the first report of successful treatment of canine cyanobacterial (microcystin) toxicosis. Untreated microcystin intoxication is commonly fatal, and can result in significant liver damage in surviving animals. The clinical success of this case suggests that oral administration of cholestyramine, in combination with supportive therapy, could significantly reduce hospitalization time, cost-of-care and mortality for microcystin-poisoned animals.     

水飞蓟宾对人膀胱癌细胞系T24和5637的增殖抑制及凋亡诱导作用

目的：探讨水飞蓟宾(SB)对人膀胱癌细胞系T24和5637增殖及凋亡的影响,初步阐明其可能的机制。方法：培养人膀胱癌细胞系5637和T24,取处于对数生长期的5637和T24细胞分为对照组(0 μmol•L^-1 SB)及25、50、100、200和400  μmol•L^-1 SB 组,MTT法检测SB对人膀胱癌细胞系T24和5637的增殖抑制作用;采用倒置显微镜观察不同浓度SB作用不同时间对人膀胱癌细胞系T24和5637的侵袭抑制能力;DAPI染色法观察给药后细胞形态;流式细胞术检测并评估SB诱导肿瘤细胞凋亡的能力。结果：MTT法检测,随着SB浓度的增加和作用时间延长,不同浓度SB组T24和5637细胞存活率显著低于对照组;不同浓度SB处理后,各组细胞的迁移明显受到抑制;DAPI染色及流式细胞术检测,不同浓度SB组T24和5637细胞凋亡率显著高于对照组（P<0.05）。结论：SB通过诱导人膀胱癌细胞系T24和5637凋亡从而抑制细胞侵袭及增殖。     

Adjuvant Therapy with Silibinin Improves the Efficacy of Paclitaxel and Cisplatin in MCF-7 Breast Cancer Cells

Herbal-derived medicines have introduced as sources of novel drugs due to minimum systemic side effects. Silibinin as a flavonoid compound has showed with effective chemotherapeutic effects on different cancers. Here, we investigated the impact of combination therapy of silibinin, with paclitaxel and cisplatin in inhibition of proliferation and induction of apoptosis in MCF-7 cells. Cell proliferation was assessed by MTT assay and the percentage of apoptotic cells was measured using flowcytometric assay. Understand of molecular mechanism of this combination related to apoptotic pathway were evaluated by Real Time RT-PCR assays. The IC50 values for silibinin, paclitaxel and cisplatin were 160 ± 22.2 μM, 33.7 ± 4.2 nM and 3.2 ± 0.5 μM, respectively. Paclitaxel and cisplatin induced higher percentage of apoptosis in MCF-7 (P < 0.05). Treatment of cell line with combination of silibinin and paclitaxel or cisplatin showed enhanced early apoptosis 56% and 61%, respectively (P < 0.05). Gene expression patterns demonstrated a significant decrease in anti-apoptotic Bcl-2 with increase in pro-apoptotic Bax, P53, BRCA1 and ATM mRNA levels. Taken together combination therapy of breast cancer cells by applying paclitaxel or cisplatin with silibinin synergistically increases the anti-proliferative effect of single agents.     

Silibinin inhibits the invasion and migration of renal carcinoma 786-O cells in vitro, inhibits the growth of xenografts in vivo and enhances chemosensitivity to 5-fluorouracil and paclitaxel

Silibinin is a flavonoid antioxidant that is widely used for its anti‐hepatotoxic properties. It exerts a dose‐dependent inhibition on the invasion and migration of 786‐O renal cell carcinoma (RCC) cells in the absence of cytotoxicity. 786‐O cells were treated with silibinin at various concentrations, up to 50 µM, for a defined period and then subjected to gelatin zymography, casein zymography, and Western blot to investigate the impacts of silibinin on metalloproteinase (MMP) ‐2, ‐9, urokinase plasminogen activator (u‐PA), and MAPK pathway signaling proteins, respectively. The results showed that silibinin decreased MMP‐2, MMP‐9, u‐PA, p‐p38, and p‐Erk1/2 expressions in a concentration‐dependent manner. The reduced expressions of MMP‐2 and u‐PA, as well as inhibition of cell invasion were obtained in the cultures pre‐treated with PD98059 (Erk1/2 inhibitor) and SB203580 (p38 inhibitor). An in vivo anti‐tumor study with a nude mice xenograft model by a subcutaneous inoculation of 786‐O cells demonstrated small solid tumors after eight days following cell inoculation. There was a 70.1% reduction in tumor volume and 69.7% reduction in tumor weight by silibinin feeding on day 44, compared to those of controls. Moreover, combination treatment with silibinin and 5‐fluorouracil, paclitaxel, vinblastine, or RAD‐001 enhanced the chemosensitivity of 5‐fluorouracil and paclitaxel. In conclusion, silibinin inhibits the invasion and migration of 786‐O cells in vitro, inhibits the growth of xenografts in vivo, and enhances chemosensitivity to 5‐fluorouracil and paclitaxel. © 2011 Wiley‐Liss, Inc.