• Biomedical Science Letters
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• v.12 no.3
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• pp.261-265
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• 2006

Toxic effect of Hexavalent chromium $(CrO_3)$ on various cells and organs has been well recognized. However, the mechanism and degree of cytotoxicity of $CrO_3$ remain unclear. This study was performed to examine the cytotoxicity of $CrO_3$ on $C_6$ glioma cells by measuring cell viability. The XTT assay, one of the sensitive methods to determine the cell viability, was taken to examine the viability of glioma cells treated with $CrO_3$. In this study, not only decreased the number of glioma cells but morphologic changes of them were noted and cell viability decreased in a time and dose-dependent manner after treated with various concentrations of $CrO_3$ for 48hours. $IC_{90}\;and\;IC_{50}$ values in XTT assay were determined at $25{\mu}M\;and\;55{\mu}M$ $CrO_3$, respectively. These results suggest that Hexavalent chromium has a highly cytotoxic effect and has a time and dose-dependent cytotoxicity on $C_6$ glioma cells.

• The Journal of Korean Medicine
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• v.39 no.4
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• pp.40-50
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• 2018

Objectives: The aim of this study is to investigate anti-inflammatory effects of Kyungheechunggan-tang (KHCGT) on LPS- induced RAW 264.7 cells and LX-2 cells and anti-fibrotic effects of KHCGT on LX-2 cells. Materials and Methods: Three types of KHCGTs (KHCGT-A, -B, and -C) by narrowing down the number of constituent herbs from 9 (KHCGT-A) to 5 (KHCGT-B) and to 3 (KHCGT-C) were developed. To understand pharmacological effects of KHCGT, three types of KHCGTs were treated on RAW 264.7 cells and LX-2 cells. Anti-inflammatory activities of KHCGT were evaluated by ELISA assay for pro-inflammatory cytokines, IL-6, $TNF-{\alpha}$ and IL-10, in LPS-stimulated RAW 264.7 cells and for IL-6 production in LPS-induced LX-2 cells. In addition, anti-fibrotic effects of KHCGT were determined by quantitative real-time PCR assay for fibrosis-related genes, ${\alpha}-SMA$, collagen1A1, TIMP1, MMP-2, in LX-2 cells. Results: KHCGT-A and KHCGT-C showed inhibitory effects on secretion of IL-6 in LPS-stimulated RAW 264.7 cells and LX-2 cells. KHCGT-B and KHCGT-C exhibited inhibitory effects on the expression of pro-inflammatory cytokines such as IL-6, $TNF-{\alpha}$, and IL-10 in LPS-stimulated RAW 264.7 cells. The mRNA expression levels of collagen1A1 and MMP-2 were significantly reduced by KHCGT-C whereas TIMP-1 was suppressed by KHCGT-A and KHCGT-B in LX-2 cells. Among three different formulas, KHCGT-C demonstrated the most remarkable effects on inflammation and fibrosis. Conclusions: In this study, KHCGT showed both anti-inflammatory and anti-fibrotic effects which make it to be a prospective agent for chronic liver diseases with inflammation and fibrosis.

• Biomedical Science Letters
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• v.12 no.3
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• pp.275-279
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• 2006

It is demonstrated that cadmium has cytotoxic effect on glial cells, oxygen radicals are involved in cadmium-induced cytotoxicity. However, the toxic mechanism of cadmium is left unknown so far. The purpose of this study was to examine the cytotoxicity of $CdCl_2$ on $C_6$ glioma cells. The cytotoxicy was measured by cell viability via XTT assay in $C_6$ glioma cells. Colorimetric assay such as XTT assay is regarded as a very sensitive screening method for the determination of the cell viability on a lots of chemicals. In this study, $CdCl_2$ decreased cell viability according to the dose- and time dependent manners after $C_6$ glioma cells were treated with various concentrations of $CdCl_2$ for 48 hours. $IC_{90}\;and\;IC_{50}$ values for XTT assay was determined at $5{\mu}M\;and\;55{\mu}M$ of $CdCl_2$, respectively. These results suggest that $CdCl_2$ has highly cytotoxic effect on $C_6$glioma cells by the decrease of cell viability.

• Molecules and Cells
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• v.43 no.9
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• pp.793-803
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• 2020

Myeloid-derived suppressor cells (MDSCs) promote tumour progression by contributing to angiogenesis, immunosuppression, and immunotherapy resistance. Although recent studies have shown that microRNAs (miRNAs) can promote the expansion of MDSCs in the tumour environment, the mechanisms involved in this process are largely unknown. Here, we report that microRNA 449c (miR-449c) expression was upregulated in myeloid progenitor cells upon activation of C-X-C motif chemokine receptor 2 (CXCR2) under tumour conditions. MiR-449c upregulation increased the generation of monocytic MDSCs (mo-MDSCs). The increased expression of miR-449c could target STAT6 mRNA in myeloid progenitor cells to shift the differentiation balance of myeloid progenitor cells and lead to an enhancement of the mo-MDSCs population in the tumour environment. Thus, our results demonstrate that the miR-449c/STAT6 axis is involved in the expansion of mo-MDSCs from myeloid progenitor cells upon activation of CXCR2, and thus, inhibition of miR-449c/STAT6 signalling may help to attenuate tumour progression.

• Natural Product Sciences
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• v.19 no.4
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• pp.360-365
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• 2013

Baicalin has antioxidant, anti-inflammatory and anti-diabetic properties. IL-6 is a primary proinflammatory cytokine that contributes to impaired insulin signaling in liver. This study was carried out to investigate whether baicalin improves IL-6-mediated insulin resistance in liver. Hepa-1c1c7 cells were pre-treated with 50 and 100 ${\mu}M$ baicalin in complete media for 1 h and then cultured in the presence or absence of IL-6 (20 ng/ml). These results demonstrated that baicalin restored IL-6-suppressed expression of insulin receptor substrate (IRS)-1 protein, downregulated IL-6-increased gene expression of C-reactive protein (CRP) and suppressor of cytokine signaling (SOCS)-3, and inhibited LPS-induced production of IL-6 in Hepa-1c1c7 cells. These findings indicate that baicalin may ameliorate hepatic insulin resistance via improvement of IL-6-mediated impaired insulin signaling in hepatocytes.

• The Journal of Korean Medicine
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• v.22 no.3
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• pp.63-73
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• 2001

Objectives : The objective of the current study is to determine the protective effect of Ukyium(Yougui-yin) on the apoptosis induced by zinc. Methods : Zinc is known to generate reactive oxygen species (ROS), including superoxide anion ($O_2$) and hydrogen peroxide ($H_2O_2$), which eventually contribute to cytotoxicity in a variety of cell types. We investigated the viablity of cells, $H_2O_2$ generation, chromatin condensation and nuclear fragmentation in Hoechst dye staining and $IkB-{\alpha}$ degradation in C6 glial cells of $ZnCl_2$ between pretreatment- and not pretreatment-group with Ukyium. The former methods were researched by Time- and Dose-dependent manners. Results : We demonstrated that pretreatment with Ukyium prevented zinc-induced cell death of C6 glial cells and apoptotic characteristics including chromatin condensation and nuclear fragmentation. Ukyium also prevented $H_2O_2-induced$ cell death. We further confirmed that Ukyium decreased zinc-induced generation of $H_2O_2$ and inhibited degradation of $IkB-{\alpha}$ by zinc in C6 glial ceHs. Conclusions : These data indicated that Ukyium (Yougui-yin) prevents zinc-induced apoptotic death of C6 glial cells via inhibition of ROS generation, such as $H_2O_2$ as well as inhibition of $IkB-{\alpha}$ degradation.

• Archives of Pharmacal Research
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• v.22 no.5
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• pp.448-453
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• 1999

In ginsenoside Rh2-treated rat glioma C6Bu-1 cells, apoptotic morphological changes, such as cell shrinkage, chromatin condensation and pyknosis were confirmed by means of electron microscopy. To evaluate whether induction of apoptosis by ginsenoside Rh2 is mediated by the members of Bcl-2 family, we first established C6Bu-1 cells overexpressing Bcl-2. It was demonstrated that the expression of Bcl-2, Bcl-xL, and Bax was not altered in ginsenoside Rh2-treated C6Bu-1 overexpressing C6Bu-1 cells failed to prevent from ginsenoside Rh2-induced cell death. These results suggest the existence of other apoptotic pathway that requires induction of apoptosis by ginsenoside Rh2 rather than the pathway through Bcl-2, $Bcl-x_{L}$ or Bax in C6Bu-1 cells.

• YAKHAK HOEJI
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• v.45 no.4
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• pp.413-418
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• 2001

To investigate action of ATP on ischemia-induced brain injury, we measured phospholipase $A_2$activity and nitric oxide (NO) production in C6 cells. ATP alone did not have any influence on phospholipase $A_2$activity but increased NO production. Glutamate (1 mM) significantly increased phospholipase $A_2$activity whereas did not increased NO production. ATP significantly inhibited phospholipase $A_2$activation induced by 0.1 $\mu$M A23187, 1 mM glutamate and 1 mM $H_2O$$_2$, but did not inhibited 1 $\mu$M PMA-induced phospholipase $A_2$activation. From the above results, it is suggested that the action of ATP in C6 cells has dual actions, such as the inhibition of agonist-induced phospholipase $A_2$activation and the increase of NO production.

• Natural Product Sciences
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• v.18 no.4
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• pp.221-226
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• 2012

Hesperidin (HES) is a bioflavonoid with antioxidant, anti-inflammatory and anti-diabetic properties. IL-6 is well known as a primary proinflammatory cytokine that contributes to impaired insulin signaling in liver. This study was to investigate whether HES improves IL-6-mediated impairment of insulin sensitivity in liver. Hepa-1c1c7 cells were pre-treated with 50 and $100{\mu}M$ HES in complete media for 1 h and then cultured in the presence or absence of IL-6 (20 ng/ml). These results demonstrated that HES restored IL-6-suppressed expression of IRS-1 protein, downregulated IL-6-increased expression of CRP and SOCS-3 mRNA, and inhibited LPS-induced production of IL-6 in Hepa-1c1c7 cells. These findings indicate that HES may ameliorate hepatic insulin resistance via improvement of IL-6-mediated impaired insulin signaling in hepatocytes.

• The Journal of Korean Medicine
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• v.22 no.3
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• pp.1-10
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• 2001

Objectives : The water extract of Nueihyuljunbang (NHJB) has long been used for treatment of ischemic brain damage in Oriental Medicine. However, little is known about the mechanism by which the water extract of NHJB recovers brain cens from ischemic damage. Methods : To elucidate the protective mechanism on ischemic induced cytotoxicity, we investigated the regulation of lipopolysaccharide (LPS) and phorbol-12-myristate-13-acetate (PMA)-induced inducible nitric oxide synthase (iNOS) expression in C6 glial cells. Results : LPS combined PMA treatment for 72 hours in C6 glial cells markedly induced nitric oxide (NO), but treatment of the cells with the water extract of NHJB decreased dose-dependently nitrite formation. In addition, LPS combined PMA treatment for 72 hours induced severe celt death and lactate dehydrogenase (LDH) release in C6 glial cells. However, treatment of the celts with the water extract of NHJB did not induce significant change compared to control cells. Furthermore, the protective effects of the water extract of NHJB were mimicked by the treatment of NGMMA, a specific inhibitor of NOS. LPS combined PMA induced iNOS activation in C6 glial cells caused chromosomal condensation and fragmentation of the nuclei by caspase activation. The treatment of C6 glial cells with the water extract of NHJB might suppress apoptosis via caspase inhibition by regulation of iNOS expression. Conclusions : From the results, we suggest that the protective effects of the water extract of NHJB against ischemic brain damage may be mediated by regulation of iNOS during ischemic condition.