• The Korean Journal of Physiology and Pharmacology
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• 제26권5호
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• pp.389-396
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• 2022

The increased expression of receptors for advanced glycation end-product (RAGE) is known as a key player in the progression of vascular remodeling. However, the precise signal pathways regulating RAGE expression in vascular smooth muscle cells (VSMCs) in the injured vasculatures are unclear. Given the importance of mitogen-activated protein kinase (MAPK) signaling in cell proliferation, we investigated the importance of MAPK signaling in high-mobility group box 1 (HMGB1)-induced RAGE expression in VSMCs. In HMGB1 (100 ng/ml)-stimulated human VSMCs, the expression of RAGE mRNA and protein was increased in association with an increase in AGE-induced VSMC proliferation. The HMGB1-induced RAGE expression was attenuated in cells pretreated with inhibitors for ERK (PD98059, 10 μM) and p38 MAPK (SB203580, 10 μM) as well as in cells deficient in ERK and p38 MAPK using siRNAs, but not in cells deficient of JNK signaling. In cells stimulated with HMGB1, the phosphorylation of ERK, JNK, and p38 MAPK was increased. This increase in ERK and p38 MAPK phosphorylation was inhibited by p38 MAPK and ERK inhibitors, respectively, but not by JNK inhibitor. Moreover, AGE-induced VSMC proliferation in HMGB1-stimulated cells was attenuated in cells treated with ERK and p38 MAPK inhibitors. Taken together, our results indicate that ERK and p38 MAPK signaling are involved in RAGE expression in HMGB1-stimulated VSMCs. Thus, the ERK/p38 MAPK-RAGE signaling axis in VSMCs was suggested as a potential therapeutic target for vascular remodeling in the injured vasculatures.

• Nutrition Research and Practice
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• 제16권5호
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• pp.577-588
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• 2022

BACKGROUND/OBJECTIVES: Poorly regulated inflammation is believed to be the most predominant factor that can result in a wide scope of diseases including atopic dermatitis (AD). Despite many studies on the effect of pear pomace in obesity-related disorders including dysregulated gut microbiota, the protective effect of pear pomace in AD is still unknown. This study aimed to evaluate the effect of pear pomace ethanol extract (PPE) on AD by inhibiting inflammation. MATERIALS/METHODS: In the in vivo experiment, 2, 4-dinitrochlorobenzene (DNCB) was applied to NC/Nga mice to induce AD-like skin lesions. After the induction, PPE was administered daily by oral gavage for 4 weeks. The clinical severity score, serum IgE levels, spleen weight, histological changes in dorsal skin, and inflammation-related proteins were measured. In the cell study, RAW 264.7 cells were pretreated with PPE before stimulation with lipopolysaccharide (LPS). Nitrite oxide (NO) production and nuclear factor kappa B (NF-𝛋B) protein expression were detected. RESULTS: Compared to the AD control (AD-C) group, IgE levels were dramatically decreased via PPE treatment. PPE significantly reduced scratching behavior, improved skin symptoms, and decreased ear thickness compared to the AD-C group. In addition, PPE inhibited the DNCB-induced expression of inducible nitrite oxide synthase (iNOS), the receptor for advanced glycation end products, extracellular signal-regulated kinase (ERK) 1/2, and NF-𝛋B. PPE inhibited the LPS-induced overproduction of NO and the enhanced expression of iNOS and cyclooxygenase-2. Moreover, the phosphorylation of ERK1/2 and NF-𝛋B in RAW 264.7 cells was suppressed by PPE. CONCLUSIONS: These results suggest that PPE could be explored as a therapeutic agent to prevent AD.

• Anatomy and Cell Biology
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• 제56권4호
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• pp.552-561
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• 2023

The endocrinology of type 2 diabetes (T2D) and its predisposing factors have been studied extensively while its skeletal effects have received negligible research despite this being a global disease. The cellular and molecular association between proximal humeral fractures and T2D has not been fully elucidated. We aimed to study bone cell quantities and immunolabel osteogenic and antiosteogenic cytokines. The study used 12-week-old rats (23 males) consisting of 8 Sprague Dawley (SD) and 15 Zucker Diabetic Sprague Dawley (ZDSD). Weekly mass measurements were taken while fasting blood glucose levels were recorded every 2 weeks with oral glucose tolerance tests conducted once every 4 weeks. Upon termination at the age of 28 weeks, humeri were fixed in 10% buffered formalin, prior to decalcification in ethylenediaminetetraacetic acid. The bone samples were then processed in ascending grades of alcohol using an automatic processor before embedding in paraffin wax. Sections were cut at 5 ㎛ thickness in a series for Haematoxylin and Eosin stain, and immunohistochemistry was performed with the anti-tartrate-resistant acid phosphatase (TRAP), anti-alkaline phosphatase (ALP), anti-bone morphogenetic protein 3 (BMP3), anti-transforming growth factor beta 1 (TGFβ1), anti-aged glycation end product (AGE) antibodies in the sequence. ZDSD rats had more adipocytes, BMP3 and AGEs expression with higher numbers of TRAP positive osteocytes and fewer ALP cells although no differences were found in TGFβ1 immunopositivity. We also found that T2D increases the number of AGEs immuno-positive cells, as well as its extracellular expression, thus providing a conducive environment for the interaction of the osteogenic cytokine and its antagonist to suppress osteoblastogenesis. ZDSD groups had higher adipocyte numbers therefore increased marrow adiposity in T2D.

• 한국식품과학회지
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• 제47권1호
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• pp.95-102
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• 2015

본 연구는 분유모델시스템에 $\small{L}$-carnitine, pyridoxine hydrochloride, $\small{DL}$-${\alpha}$-tocopheryl acetate를 첨가하여 Maillard 반응에 의해 생성된 MRPs를 저감화 시키기 위한 최적조건을 찾기 위해 RSM의 CCD를 이용하였다. $\small{L}$-Carnitine ($X_1$), pyridoxine hydrochloride($X_2$), $\small{DL}$-${\alpha}$-tocopheryl acetate ($X_3$)의 농도를 독립변수로 하고 형광도와 HMF 함량을 종속변수로 각각 설정하였다. 종속변수 회귀식의 결정계수($R^2$)는 각각 0.942, 0.861로 반응표면분석 모델에 적합하였다. 형광도와 HMF 함량은 $\small{L}$-carnitine과 pyridoxine hydrochloride의 농도가 낮을 때 $\small{DL}$-${\alpha}$-tocopheryl acetate의 농도가 감소할수록 그 값이 급격히 감소하였다. $\small{L}$-Carnitine의 농도가 높을 때 pyridoxine hydrochloride의 농도가 $20{\mu}M$ 이하로 감소할수록 형광도가 감소하였고 HMF 함량은 $\small{L}$-carnitine의 농도에 관계없이 pyridoxine hydrochloride의 농도가 $20{\mu}M$ 이하로 감소할수록 감소하는 경향을 나타냈다. 본 실험에서 분유모델시스템에서 생성된 MRPs를 저감화 할 수 있는 최적조건으로 $\small{L}$-carnitine, pyridoxine hydrochloride, $\small{DL}$-${\alpha}$-tocopheryl acetate의 농도는 각각 2.26, 15.77, $20.63{\mu}M$이었다. 이때 형광도는 77.4%였고 HMF 함량은 248.7 ppb로 각각 유단백질-유당 마이얄 반응생성물(LC, lactose+sodium caseinate)대비 MRPs를 22.6, 23.1% 감소시킬 수 있다고 예측할 수 있었다. 또한, RSM을 통해 찾은 최적 조건의 실험값으로 형광도는 79.3%였고 HMF 함량은 247.6 ppb로 각각 LC대비 MRPs를 20.7, 17.8% 감소 시켰다. 따라서, $\small{L}$-carnitine, pyridoxine hydrochloride, $\small{DL}$-${\alpha}$-tocopheryl acetate의 최적화된 혼합을 통하여 분유 제조 시 MRPs 생성을 저감화 시킬 수 있을 것으로 생각된다.

• 한국식품영양과학회지
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• 제40권3호
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• pp.385-392
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• 2011

Glyceraldehyde를 이용하여 제조된 AGEs 화합물(glycer-AGEs)을 단구세포인 THP-1, 혈관내피세포인 HUVEC 및 이 두 세포가 동시에 배양된 system에서 100 ${\mu}g/mL$로 처리 후 24시간까지 처리시간을 달리하여 처리하였다. 배양시간 동안 각 세포와 배양액을 회수하여 TNF-$\alpha$와 IL-1$\beta$의 발현을 mRNA 수준에서 조사하였다. 그 결과, THP-1의 경우 배양 2시간에서 TNF-$\alpha$나 IL-1$\beta$의 mRNA 발현이 대조구에 비해 증가되었으나 혈관내피세포인 HUVEC의 경우에는 24시간 배양하는 동안 유의적인 차이가 없었다. 그러나 두세포를 동시에 배양한 system에서 혈관내피세포인 HUVEC의 경우에는 배양 4시간에서 대조구보다 TNF-$\alpha$의 발현은 4.4배, IL-1$\beta$의 경우 5.5배 정도 증가되는 것을 확인할 수 있었다. TNF-$\alpha$와 IL-1$\beta$의 배지 내에서의 농도를 측정해 본 결과, THP-1만 배양한 경우 대조구의 배지 내 TNF-$\alpha$ 함량이 배양 6시간에 98.2 pg/mL로 대조구 53.8 pg/mL보다 증가하였으며 HUVEC의 경우 배양 8시간에 93.3 pg/mL로 증가하였다. 그러나 co-culture의 경우 배양 4시간부터 증가하여 배양 8시간에 199.2 pg/mL로 증가하였다. RAGE는 TNF-$\alpha$와 IL-1$\beta$의 발현 pattern과 다르게 단독 및 co-culture에서 배양 16시간에 대조구에 비해 각각 1.6배, 24시간에 1.9배 증가하였다. 따라서 본 연구 결과 최종당화산물에 의해 혈관내피세포의 기능상실의 연구에 있어 co-culture조건이 유용하며, 특히 mRNA 수준에서는 4시간에, protein 수준에서는 8시간에 효능을 측정하면 유효성 있는 연구 성과를 얻을 있을 것으로 예측할 수 있었다.

• 한국식품과학회지
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• 제43권2호
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• pp.195-199
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• 2011

본 연구에서는 늙은호박(Cucurbita moschata Duch.)의 부위별 항산화 효과 및 생리활성을 평가하기 위하여 잎과 과피, 과육과 씨 네 부분으로 나누어 일반성분을 측정하고, 환류 추출과 감압농축 및 동결건조를 통하여 분말을 얻은 후 실험에 사용하였다. 호박의 부위별 총 폴리페놀 함량은 잎이 $29.62{\pm}0.88mg$ GAE/g DM로 가장 높게 측정되었다. 플라보노이드 함량도 잎이 가장 높고 과피, 과육, 씨의 순서로 측정되어 폴리페놀 함량과 같은 경향을 보였다. DPPH radical 소거 활성과 ABTS radical 소거 활성에서 SC50값을 측정하였을 때는 잎에서 가장 높은 소거 활성을 나타내었다(DPPH: $1.27{\pm}0.14$, ABTS: $2.28{\pm}0.05$). FRAP assay를 이용한 환원력을 실험한 결과에서도 잎에서 가장 높은 환원력이 관찰되었다. 한편, 생리활성적인 측면 중 tyrosinase 효소 억제 활성 능력은 대조군인 kojic acid와 비교하였을 때 같은 농도인 0.1 mg/mL에서 20.70%이었던 반면 실험군인 잎은 49.58%, 과육은 40.20%을 보였고, 과피는 41.30%, 씨는 36.79%가 관찰되어 모두 이보다 높은 수치를 나타냈으므로 kojic acid 보다 효과가 있는 것을 확인할 수 있었다. 최종당화산물(AGEs) 생성억제 효능에서는 잎(65.85%), 과피(50.14%), 과육(13.72%), 그리고 씨(11.18%)의 순서로 관찰되었다. ${\alpha}$-Glucosidase 저해활성은 씨 부분의 저해활성이 63.58%로 67.28%를 나타낸 대조군 0.06 mM acarbose에 근접한 수치를 나타내었다.

• 대한수의학회지
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• 제50권2호
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• pp.105-111
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• 2010

Carnosine is a dipeptide $(\beta-alanyl-L-histidine)$ found in mammalian brain, eye, olfactory bulb and skeletal muscle at high concentrations. Its biological functions include antioxidant and anti-glycation activities. The objectives of this study were to investigate anti-diabetic effects of carnosine as determined by blood glucose levels, glucose tolerance test (GTT), glycosylated hemoglobin, and serum biochemical and lipid levels in streptozotocin-induced diabetic mice. There were five experimental groups including normal (ICR mice), control (saline), and three groups of carnosine at doses of 6, 30, and 150 mg/kg b.w.. Carnosine was orally administered to the diabetic mice everyday for 12 weeks. There was no significant difference in body weight changes in carnosine-treated groups compared to the control. The treatments of carnosine at the dose of 6 mg/kg significantly decreased the blood glucose level compared with the control at 2 and 4 weeks. The treatments of carnosine at the doses of 6 and 30 mg/kg significantly decreased the blood glucose levels in GTT and glycosylated hemoglobin compared with the control. Carnosine significantly increased total proteins compared with the control. Carnosine at the dose of 6 mg/kg significantly decreased total cholesterol and triglyceride in the serum compared to the control. These results suggest that carnosine at a low level has a hypoglycermic effect resulting from reduction of blood glucose and that a carnosine-containing diet or drug may give a benefit for controlling diabetes mellitus in humans.

• Journal of Acupuncture Research
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• 제33권3호
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• pp.29-43
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• 2016

Objectives : The purpose of this study was to investigate the effect of LR3 and SP6 acupuncture on liver damage of streptozotocin-induced diabetic mice. Methods : Male ICR mice were divided into four groups, consisting of the normal mice group(N), acupuncture-free diabetic mice group(Con), LR3-acupuncture diabetic mice group(LR3) and SP6-acupuncture diabetic mice group(SP6). The following measurements were taken: Body weight, food intake and water intake for 2 weeks; liver weight, and glucose levels in the serum and liver; ALT and AST in the serum; reactive oxygen species(ROS), reduced glutathione(GSH) and oxidized glutathione(GSSG) in the liver; and lastly, receptor for advanced glycation endproducts( RAGE), $N{\varepsilon}-carboxymethyl$ lysine(CML), $N{\varepsilon}-carboxyethyl$ lysine(CEL), phosphorylation of inhibitory kappa B alpha($p-I{\kappa}B{\alpha}$), nuclear factor-kappa B($NF-{\kappa}B$), activator protein-1(AP-1), cyclooxygenase-2(COX-2), inducible nitric oxide synthase(iNOS), tumor necrosis factor-alpha($TNF-{\alpha}$), ${\beta}-actin$, cytochrome c and caspase in the liver. Results : The liver weight and GSH/GSSG ratio were significantly increased in SP6 compared to Con. The glucose levels in the liver were significantly decreased in LR3 compared to Con. The generation of ROS and GSSG were significantly decreased in SP6 compared to Con. The expressions of RAGE, CML, AP-1, $TNF-{\alpha}$, cytochrome c and caspase 3 were significantly decreased in LR3 compared to Con. The expressions of $p-I{\kappa}B{\alpha}$, $NF-{\kappa}B$, AP-1, COX-2, iNOS and caspase 3 were significantly decreased in SP6 compared to Con. Conclusion : It is predicted that LR3 acupuncture is related to reduced glucose levels in the liver and expressions of AGE, and that, SP6 acupuncture is related to reduced oxidative stress-related transcription factors and inflammation-related proteins. Therefore, we suggest that LR3 and SP6 acupuncture have protective effects on the liver of streptozotocin-induced diabetic mice by preventing apoptosis.

• 대한화장품학회지
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• 제18권1호
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• pp.64-80
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• 1992

Collagen은 세포 외에 존재하며, 분자의 수명이 매우 긴 단백질이므로, 노화와 관련된 비효소적 당화의 대상으로 많은 관심이 모아지고 있다. 본 연구에서는 진피 collagen의 비효소적 당화와 분해 및 가교결합에 대한 자외선(UVA)과 활성산소종들의 영향을 검토하였다. 암소 피부로부터 얻은 collagen 과 glucose의 혼합물에 몇가지 활성산소 소거제를 첨가하고 UVA를 조사하여 비효소적 당화, 단백질 분해, 가교결합의 정도를 관찰하였다. 비효소적 당화는 자외선에 의해 증가되지 않았으며, 수퍼옥사이드 라디칼과 일중항 산소의 소거제에 의해서는 감소하였으나, 히드록시 라디칼 소거제에 의해서는 변화가 없었다. 단백질 분해와 가교결합은 자외선에 의해 증가되었으며, 분해는 세가지 활성산소의 소거제 모두에 의해 감소되었으나, 가교결합은 특히 히드록시 라디칼 소거제의 영향이 컸다. 즉 수퍼옥사이드 라디칼과 일중항 산소는 자외선과는 관계 없이 당의 자동산화에 의해 발생되어 당화로 인한 변화의 초기 단게에 관여하고, 반응의 뒷부분에서는 당단백질과 자외선에 의해 만들어진 히드록시 라디칼이 주된 역할을 하고 있다. 상기의 결과로부터 활성산소종들과 자외선은 다른 조직 및 세포물질들을 손상시키듯이 노화와 관련된 collagen 변화를 증가시키는 것을 알 수 있었다. 이는 자외선 차단제와 함께 활성산소 소거 물질들을 외용도포하는 것이 태양광선의 해로운 영향으로부터 진피를 보호하는데 도움이 될 수 있음을 의미한다.

• Experimental and Molecular Medicine
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• 제50권11호
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• pp.13.1-13.15
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• 2018

Wound healing is delayed in diabetic patients. Increased apoptosis and endothelial progenitor cell (EPC) dysfunction are implicated in delayed diabetic wound healing. Melatonin, a major secretory product of the pineal gland, promotes diabetic wound healing; however, its mechanism of action remains unclear. Here, EPCs were isolated from the bone marrow of mice. Treatment of EPCs with melatonin alleviated advanced glycation end product (AGE)-induced apoptosis and cellular dysfunction. We further examined autophagy flux after melatonin treatment and found increased light chain 3 (LC3) and p62 protein levels in AGE-treated EPCs. However, lysosome-associated membrane protein 2 expression was decreased, indicating that autophagy flux was impaired in EPCs treated with AGEs. We then evaluated autophagy flux after melatonin treatment and found that melatonin increased the LC3 levels, but attenuated the accumulation of p62, suggesting a stimulatory effect of melatonin on autophagy flux. Blockage of autophagy flux by chloroquine partially abolished the protective effects of melatonin, indicating that autophagy flux is involved in the protective effects of melatonin. Furthermore, we found that the AMPK/mTOR signaling pathway is involved in autophagy flux stimulation by melatonin. An in vivo study also illustrated that melatonin treatment ameliorated impaired wound healing in a streptozotocin-induced diabetic wound healing model. Thus, our study shows that melatonin protects EPCs against apoptosis and dysfunction via autophagy flux stimulation and ameliorates impaired wound healing in vivo, providing insight into its mechanism of action in diabetic wound healing.