Long noncoding RNAs HAND2-AS1 ultrasound microbubbles suppress hepatocellular carcinoma progression by regulating the miR-873-5p/tissue inhibitor of matrix metalloproteinase-2 axis

BACKGROUND Increasing data indicated that long noncoding RNAs(lncRNAs)were directly or indirectly involved in the occurrence and development of tumors,including hepatocellular carcinoma(HCC).Recent studies had found that the expression of lncRNA HAND2-AS1 was downregulated in HCC tissues,but its role in HCC progression is unclear.Ultrasound targeted microbubble destruction mediated gene transfection is a new method to overexpress genes.AIM To study the role of ultrasound microbubbles(UTMBs)mediated HAND2-AS1 in the progression of HCC,in order to provide a new reference for the treatment of HCC.METHODS In vitro,we transfected HAND2-AS1 siRNA into HepG2 cells by UTMBs,and detected cell proliferation,apoptosis,invasion and epithelial-mesenchymal transition(EMT)by cell counting kit-8 assay,flow cytometry,Transwell invasion assay and Western blotting,respectively.In addition,we transfected miR-837-5p mimic into UTMBs treated cells and observed the changes of cell behavior.Next,the UTMBs treated HepG2 cells were transfected together with miR-837-5p mimic and tissue inhibitor of matrix metalloproteinase-2(TIMP2)overexpression vector,and we detected cell proliferation,apoptosis,invasion and EMT.In vivo,we established a mouse model of subcutaneous transplantation of HepG2 cells and observed the effect of HAND2-AS1 silencing on tumor formation ability.RESULTS We found that UTMBs carrying HAND2-AS1 restricted cell proliferation,invasion,and EMT,encouraged apoptosis,and HAND2-AS1 silencing eliminated the effect of UTMBs.Additionally,miR-873-5p targets the gene HAND2-AS1,which also targets the 3’UTR of TIMP2.And miR-873-5p mimic counteracted the impact of HAND2-AS1.Further,miR-873-5p mimic solely or in combination with pcDNA-TIMP2 had been transformed into HepG2 cells exposed to UTMBs.We discovered that TIMP2 reversed the effect of miR-873-5p mimic caused by the blocked signalling cascade for matrix metalloproteinase(MMP)2/MMP9.In vivo results showed that HAND2-AS1 silencing significantly inhibited tumor formation in mice.CONCLUSION LncRNA HAND2-AS1 promotes TIMP2 expression by targeting miR-873-5p to inhibit HepG2 cell growth and delay HCC progression.

A matrix metalloproteinase-responsive hydrogel system controls angiogenic peptide release for repair of cerebral ischemia/reperfusion injury

Vascular endothelial growth factor and its mimic peptide KLTWQELYQLKYKGI(QK)are widely used as the most potent angiogenic factors for the treatment of multiple ischemic diseases.However,conventional topical drug delivery often results in a burst release of the drug,leading to transient retention(inefficacy)and undesirable diffusion(toxicity)in vivo.Therefore,a drug delivery system that responds to changes in the microenvironment of tissue regeneration and controls vascular endothelial growth factor release is crucial to improve the treatment of ischemic stroke.Matrix metalloproteinase-2(MMP-2)is gradually upregulated after cerebral ischemia.Herein,vascular endothelial growth factor mimic peptide QK was self-assembled with MMP-2-cleaved peptide PLGLAG(TIMP)and customizable peptide amphiphilic(PA)molecules to construct nanofiber hydrogel PA-TIMP-QK.PA-TIMP-QK was found to control the delivery of QK by MMP-2 upregulation after cerebral ischemia/reperfusion and had a similar biological activity with vascular endothelial growth factor in vitro.The results indicated that PA-TIMP-QK promoted neuronal survival,restored local blood circulation,reduced blood-brain barrier permeability,and restored motor function.These findings suggest that the self-assembling nanofiber hydrogel PA-TIMP-QK may provide an intelligent drug delivery system that responds to the microenvironment and promotes regeneration and repair after cerebral ischemia/reperfusion injury.

Highly Aligned Ternary Nanofiber Matrices Loaded with MXene Expedite Regeneration of Volumetric Muscle Loss

Current therapeutic approaches for volumetric muscle loss(VML)face challenges due to limited graft availability and insufficient bioactivities.To overcome these limitations,tissue-engineered scaffolds have emerged as a promising alternative.In this study,we developed aligned ternary nanofibrous matrices comprised of poly(lactide-co-ε-caprolactone)integrated with collagen and Ti_(3)C_(2)T_(x)MXene nanoparticles(NPs)(PCM matrices),and explored their myogenic potential for skeletal muscle tissue regeneration.The PCM matrices demonstrated favorable physicochemical properties,including structural uniformity,alignment,microporosity,and hydrophilicity.In vitro assays revealed that the PCM matrices promoted cellular behaviors and myogenic differentiation of C2C12 myoblasts.Moreover,in vivo experiments demonstrated enhanced muscle remodeling and recovery in mice treated with PCM matrices following VML injury.Mechanistic insights from next-generation sequencing revealed that MXene NPs facilitated protein and ion availability within PCM matrices,leading to elevated intracellular Ca^(2+)levels in myoblasts through the activation of inducible nitric oxide synthase(i NOS)and serum/glucocorticoid regulated kinase 1(SGK1),ultimately promoting myogenic differentiation via the m TOR-AKT pathway.Additionally,upregulated i NOS and increased NO–contributed to myoblast proliferation and fiber fusion,thereby facilitating overall myoblast maturation.These findings underscore the potential of MXene NPs loaded within highly aligned matrices as therapeutic agents to promote skeletal muscle tissue recovery.

关于两类特殊矩阵2-范数界的估计

矩阵的2-范数是对矩阵进行度量的一种方法,它在数值计算、优化问题、机器学习等领域都具有重要的应用.为此,首先推导了Pell和Pell-Lucas数的几个平方和公式.其次分别构造了以Pell或Pell-Lucas数为元素的Hankel-Hessenberg矩阵和Toeplitz-Hessenberg矩阵.最后讨论了这两类矩阵的2-范数的上下界.

Suppression of matrix metalloproteinase-2 via RNA interference inhibits pancreatic carcinoma cell invasiveness and adhesion

AIM:To investigate the inhibitory effects of RNA interference (RNAi) on expression of matrix metalloproteinase-2 (MMP-2) gene and invasiveness and adhesion of human pancreatic cancer cell line,BxPC-3.METHODS:RNAi was performed using the vector (pGPU6)-based small interference RNA (siRNA) plasmid gene silence system to specifically knock down MMP-2 expression in pancreatic cancer cell line,BxPC-3. Four groups of different specific target sequence in coding region of MMP-2 and one non-specific sequence were chosen to construct four experimental siRNA plasmids of pGPU6-1,pGPU6-2,pGPU6-3 and pGPU6-4,and one negative control siRNA plasmid of pGPU6 (-). MMP-2 expression was measured by reverse transcription polymerase chain reaction (RT-PCR) and Western blot. Cell proliferation and apoptosis were examined by methyl thiazolyl tetrazolium (MTT) and flow cytometry,respectively. The abilities of adhesion and invasion were detected by cell adhesion assay and cell invasion assay using Transwell chambers.RESULTS:The expression of MMP-2 was inhibited and the inhibitory effects of different sequence varied. pGPU6-1 group had the most efficient inhibitory effect,followed by pGPU6-2 and pGPU6-3 groups.Invasiveness and adhesion were more significantly reduced in pGPU6-1,pGPU6-2 and pGPU6-3 groups as compared with pGPU6 (-) and blank control groups. However,no difference concerning cell proliferation and apoptosis was observed after transfection between experiment groups and control groups.CONCLUSION:RNAi against MMP-2 successfully inhibited the mRNA and protein expression of MMP-2 in the pancreatic cancer cell line,BxPC-3,leading to a potent suppression of tumor cell adhesion and invasion without affecting cell proliferation and apoptosis. These findings suggest that the RNAi approach towards MMP-2 may be an effective therapeutic strategy for the clinical management of pancreatic tumor.

Relationship between matrix metalloproteinase-2 mRNA expression and clinicopathological and urokinase-type plasminogen activator system parameters and prognosis in human gastric cancer

AIM: To investigate the relationship between matrix metalloproteinase-2 (MMP-2) mRNA expression and clinicopathologic and urokinase-type plasminogen activator (uPA) system parameter and prognosis in human gastric cancer. METHODS: Expression of MMP-2 mRNA, uPA, and uPA-R mRNA in tumor tissues and ≥5 cm adjacent normal tissues from 67 cases of gastric cancer was studied using RT-PCR and Northern blot respectively.Survival analyses were done using the Kaplan-Meier method. RESULTS: The expression rates of MMP-2 mRNA,uPA and uPA-R mRNA in tumor tissues (31%,41%,and 51%, respectively) were significantly higher than those in ≥5 cm adjacent tissues (19%, 11%, and 9%; X2=4.59,43.58, and 53.24 respectively, P<0.05,0.0001,and 0.0001, respectively). Expression of MMP-2 mRNA was significantly correlated with lymph node metastasis (metastasis: 61.9%, no metastasis: 39.1%, X2= 7.61, P<0.05),Lauren's classification of diffuse/mixed types:54.2%,intestinal type: 26.3%,X2 = 4.25, P<0.05, expression of uPA and uPA-R mRNA (uPA+: 55.1%, uPA-: 22.2% and uPA-R+: 54.9%, uPA-R-: 18.8%, X2=5.72 and 6.40 respectively, P<0.05).Kaplan-Meier survival analysis of MMP-2 mRNA expression did not show significant difference in all 67 cases, but revealed an association of the expression of MMP-2 mRNA, uPA, and uPA-R mRNA with worse prognosis (P= 0.0083, 0.0160, and 0.0094, respectively). CONCLUSION: MMP-2 may play an important role in the development of invasion and metastasis of gastric cancer.

Correlation of RECK with Matrix Metalloproteinase-2 in Regulation of Trophoblast Invasion of Early Pregnancy

To study the role of the reversion-inducing-cysteine-rich protein with Kazal motifs （RECK） gene and matrix metalloproteinase-2 （MMP-2） in the regulation of trophoblast invasion of early pregnancy. Immunohistochemistry, Western blot and gelatin zymography were used to detect the RECK protein expression localization, expression level and MMP-2 activation level in the placental tissues harvested from 52 normal pregnant women （27 in the early pregnancy, 25 in the term pregnancy）. Immunohistochemistry showed that RECK expression was found both in villous tissues of early pregnancy group and term pregnancy group and was mainly observed in cell membrane and cytoplasm of cytotrophoblasts and syneytiotrophoblasts. RECK expression increased with gestational time. RECK expression of early pregnancy group was significantly lower than that of term pregnancy group （P〈0.05）. RECK expression was significantly lower in cellular column （CC） with invasion ability. Western blot showed that the RECK protein expression in early pregnancy group was significantly lower than that in term pregnancy （P〈0.05）. The optical density values of RECK protein expression in early pregnancy group and term pregnancy group were 1.35±0.14 and 2.68±0.26, respectively, while MMP-2 activation ratio was contrary to RECK protein expression and decreased with the gestation time （P〈0.01）. The MMP-2 activation ratios of early pregnancy group and term pregnancy group were 0.46±0.05 and 0.10±0.02, respectively. The expression of the tumor inhibitory gene RECK was positively related with the invasion ability of trophoblasts, while the invasion gene MMP-2 was negatively related with the ability. The interaction between RECK and MMP-2 may play an important role in the regulation of the trophoblast invasion in early pregnancy.

Distribution and relative activity of matrix metalloproteinase-2 in human coronal dentin

The presence of matrix metalloproteinase-2 （MMP-2） in dentin has been reported, but its distribution and activity level in mature human coronal dentin are not well understood. The purpose of this study was to determine the MMP-2 distribution and relative activity in demineralized dentin. Crowns of twenty eight human molars were sectioned into inner （ID）, middle （MD）, and outer dentin （OD） regions and demineralized. MMP-2 was extracted with 0.33 mol·L-1 EDTA/2 mol·L-1 guanidine-HCl, pH 7.4, and MMP-2 concentration was estimated with enzyme-linked immunoabsorbant assay （ELISA）. Further characterization was accomplished by Western blotting analysis and gelatin zymography. The mean concentrations of MMP-2 per mg dentin protein in the dentin regions were significantly different （P=0.043）： 0.9 ng （ID）, 0.4 ng （MD）, and 2.2 ng （OD）, respectively. The pattern of MMP-2 concentration was OD〉ID〉MD. Western blotting analysis detected -66 and -72 kDa immunopositive proteins corresponding to pro- and mature MMP-2, respectively, in the ID and MD, and a -66 kDa protein in the OD. Gelatinolytic activity consistent with MMP-2 was detected in all regions. Interestingly, the pattern of levels of Western blot immunodetection and gelatinolytic activity was MD〉ID〉OD. The eoneentration of MMP-2 in human coronal dentin was highest in the region of dentin that contains the dentinoenamel junction and least in the middle region of dentin. However, levels of Western blot immunodetection and gelatinolytic activity did not correlate with the estimated regional concentrations of MMP-2, potentially indicating region specific protein interactions.

Preparation and in vitro studies of microencapsulated cells releasing human tissue inhibitor of metalloproteinase-2

Objective： To prepare microencapsulated cells releasing human tissue inhibitor ofmetalloproteinase-2 （TIMP-2）, and investigate their biological characteristics in vitro. Methods： Chinese hamster ovary （CHO） cells were stably transfected with a human TIMP-2 expression vector, encapsulated in barium alginate microcapsules and cultured in vitro. Morphological appearance of the microcapsules was observed under a light microscope. Cell viability was assessed using MTT （3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide） assay. Enzyme linked immunosorbent assay （ELISA） and reverse zymography were used to confirm the release of biologically active TIMP-2 from the microcapsules. Cryopreservation study of the microencapsulated cells was carried out using dimethyl sulfoxide （DMSO） as preservative agent. Results： The microcapsules appeared like a sphere with diameter of 300-600 ~tm. The surface of the capsule wall was clearly smooth. The microencapsulated cells survived well and kept proliferating over the 6 weeks observed. No significant difference in TIMP-2 secretion was found between encapsulated and unencapsulated cells. Reverse zymography confirmed the bioactivity of MMP （matrix metalloproteinase） inhibition of TIMP-2. The cryopreservation process did not damage the microcapsule morphology nor the viability of the cells inside. Conclusion： Microencapsulated engineered CHO cells survive at least 6 weeks after preparation in vitro, and secrete bioactive TIMP-2 freely from the microcapsules.

The Explicit Expressions of Level- k(r1 ,r2 ,… ,rk) Circulant Matrices and Their Some Properties

In this paper,we give the explicit expressions of level k (r 1,r 2,…,r k) circulant matrices of order n 1n 2…n k,and the explicit expressions for the eigenvalues,the determinants and the inverse matrices of the kind level k (r 1,r 2,…,r k) circulant matrices are derived,and it is also proved that the sort of matrices are diagonalizable.

Effects of hypoxia,hyperoxia on the regulation of expression and activity of matrix metalloproteinase-2 in hepatic stellate cells

AIM: To study the effects of hypoxia, hyperoxia on the regulation of expression and activity of matrix metalloproteinase-2 (MMP-2) in hepatic stellate cells (HSC). METHODS: The expressions of MMP-2, tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) and membrane type matrix metalloproteinase-1 (MT1-MMP) in cultured rat HSC were detected by immunocytochemistry (ICC) and in situ hybridization (ISH). The contents of MMP-2 and TIMP-2 in culture supernatant were detected with ELISA and the activity of MMP-2 in supernatant was revealed by zymography. RESULTS: In the situation of hypoxia for 12h, the expression of MMP-2 protein was enhanced (hypoxia group positive indexes: 5.7 +/- 2.0, n=10; control: 3.2 +/- 1.0, n = 7; P【0.05), while TIMP-2 protein was decreased in HSC (hypoxia group positive indexes: 2.5 +/- 0.7, n = 10; control: 3.6 +/- 1.0, n = 7; P 【 0.05), and the activity (total A) of MMP-2 in supernatant declined obviously (hypoxia group: 7.334 +/- 1.922, n = 9; control: 17.277 +/- 7.424, n = 11; P 【 0.01). Compared the varied duration of hypoxia, the changes of expressions including mRNA and protein level as well as activity of MMP-2 were most notable in 6h group. The highest value(A(hypoxia)-A(control)) of the protein and the most intense signal of mRNA were in the period of hypoxia for 6h, along with the lowest activity of MMP-2. In the situation of hyperoxia for 12h, the contents (A(450)) of MMP-2 and TIMP-2 in supernatant were both higher than those in the control, especially the TIMP-2 (hyperoxia group: 0.0499 +/- 0.0144, n = 16; control: 0.0219 +/- 0.0098, n = 14; P 【 0.01), and so was the activity of MMP-2 (hyperoxia group: 5.252 +/- 0.771, n = 14; control: 4.304 +/- 1.083, n = 12; P 【 0.05), and the expression of MT1-MMP was increased. CONCLUSION: HSC is sensitive to the oxygen, hypoxia enhances the expression of MMP-2 and the effect is more marked at the early stage; hyperoxia mainly raises the activity of MMP-2.

Expressions of cyclooxygenase-2 and matrix metalloproteinase-9 in cervical carcinoma and their clinical significance

Objective: To investigate the expressions of cyclooxygenase (COX)-2 and matrix metalloproteinase (MMP)-9 in cervical carcinoma and their clinical significance. Methods: Immunohistochemistry SP method was used to detect the expres- sions of COX-2 and MMP-9 in 72 cases of invasive carcinoma of cervix (ICC) and 16 cases of normal cervical epithelium remote from tumor (NCE). The relationships between the expressions of COX-2, MMP-9 in ICC and some characteristics relating to clinical pathology of cervical carcinoma such as histological grading, lymph node metastasis, stromal invasion and FIGO stage were analyzed statistically. Results: The rates of the positive expressions of COX-2 and MMP-9 in ICC were significantly higher than those in NCE. COX-2: 88.9% (64/72) in group ICC and 12.5% (2/16) in group NCE, P = 0.000; MMP-9: 94.4% (68/72) in group ICC and 43.8% (7/16) in group NCE, P = 0.000. The expression of COX-2 was positively correlated with lymph node metastasis (r = 0.296, P = 0.012) and stromal invasion (r = 0.257, P = 0.029). The expression of MMP-9 was positively correlated with FIGO stage (r = 0.329, P = 0.005) and histological grading (r = 0.351, P = 0.003). The expression of COX-2 was positively correlated with the expression of MMP-9 in ICC (r = 0.297, P = 0.011). Conclusion: The overexpressions of COX-2 and MMP-9 were closely related to the invasion and growth of cervical carcinoma. The tissue with the overexpression of COX-2 had strong invasion ability. COX-2 and MMP-9 had synergistic effect on proliferation, invasion and metastasis of cancer cells. Detecting the coexpression of COX-2 and MMP-9 may be of value in further understanding the biological behavior and predicting the prognosis of cervical carcinoma.

Vascular Endothelial Growth Factorl65-regulated Nasopharyngeal Carcinoma Cell Lines Invasion and Migration Involve Expression and Activation of Matrix Metalloproteinase-2

The effect of vascular endothelial growth factor （VEGF） overexpression on matrix metalloproteinase-2 （MMP-2） in nasopharyngeal carcinoma （NPC） cells in vitro and the possible mechanism involved were investigated, and the correlation between the expression of VEGF and MMP-2 in NPC evaluated. The NPC cells were transfected with PAd-trackVEGF165 plasmid. The expression levels of VEGF and MMP-2 mRNA and protein in NPC cells were detected by semi-quantitative RT-PCR and Western blot respectively. It was found that the expression of VEGF and MMP-2 mRNA and protein was significantly increased in NPC cells after transfection of VEGF 165. It was concluded that the expression of VEGF was correlated to the in vitro invasion of NPC cells, and the induction of MMP-2 by VEGF was a key process of NPC cell invasion.

Influence of hydrogen sulfide on zymogen activation of homocysteineinduced matix metalloproteinase-2 in H9C2 cardiocytes

Objective: To observe the influence of different concentrations of homocysteine(Hcy) and hydrogen sulfide(H2S) on the secretion and activation of matix metalloproteinase-2(MMP-2) in cardiocytes so as to search for new ways to fight against myocardial tissue fibrosis. Methods: Cardiocytes H9C2 was cultured in vitro and different concentrations of Hcy and H2 S were added for 6-h and 24-h cultivation. MTT cell proliferation assay was applied to test the activation change of cardiocytes H9C2 after affecting by different concentrations of Hcy and H2 S. ELISA and MTT were employed to detect the expression and enzymatic activity of MMP-2. Results: The H9C2 cell inhibition of activity was more significant with 1 000 μmol/L of Hcy as compared with other concentrations(P<0.001). With 2.5-100.0 μmol/L Hcy and 0.1, 1.0 and 10.0 mmol/L H2 S, the activity of H9C2 did not change significantly(P>0.05). Hcy with concentrations of 10, 50 and 100 μmol/L could increase the quantity of MMP-2 secreted by cardiocytes H9C2, and the interaction strength was concentration-dependent(P<0.05). After interacting with 100 μmol/L of Hcy for 6 h, the zymogen activation effect of MMP-2 was stronger than that of the 2.5-25 μmol/L group(P<0.05). After interacting with Hcy and H2S(1.0 mmol/L) for 6 h and 24 h, the activation effect of MMP-2 was stronger than those interacted with 10, 25, 50 and 100 μmol/L of Hcy(P<0.05). Conclusions: Hcy can increase the production of MMP-2 secreted by H9C2 cell and improve its zymogen activation. Besides, the interaction strength is concentration-dependent; while H2 S can up-regulate the activation of MMP-2 and co-promote the activation of MMP-2 with Hcy as well.

Nonsingularity on Level-2(r_1, r_2)-circulant Matrices of Type (m,n)

In this pape,we give four methods of discriminations its nonsingularity by utilizing only parametr r1,r2 and elements of the first row of level-2 (r1, r2)-circulant matrices of type (m,n).

The Explicit Expressions of Level-k Circulant Matrices of Type(n_1,n_2.…,n_k) and Their Some Properties

In this paper, we give the explicit expressions of level-k circulant matrices of type (n1,n2,…nk) and of order n1n2…nk,and the explicit expressions for the eigenvalues,the determinants and the inverse matrices of the kind level-k circulant matrices are derived,and it is also proved that the sort matrices are unitarily diagonalizable.

All-trans retinoic acid regulates the expression of MMP-2 and TGF-β2 via RDH5 in retinal pigment epithelium cells

·AIM: To investigate the effect of all-trans retinoic acid(ATRA) on retinol dehydrogenase 5(RDH5), matrix metalloproteinase-2(MMP-2) and transforming growth factor-β2(TGF-β2) transcription levels, and the effect of RDH5 on MMP-2 and TGF-β2 in retinal pigment epithelium(RPE) cells.·METHODS: After adult RPE cell line-19(ARPE-19 cells) intervened with gradient concentrations of ATRA(0-20 μmol/L) for 24h, flow cytometry was used to detect the proliferation and apoptosis of cells in each group, and quantitative realtime polymerase chain reaction(q RT-PCR) was used to detect RDH5, MMP-2 and TGF-β2 m RNA expression. Then, after ARPE-19 cells transfected with three different si RNA targets for 48h, the RDH5 knockdown efficiency of each group and expression of MMP-2 and TGF-β2 m RNA within them was detected by q RT-PCR. ·RESULTS: Flow cytometry results showed that ATRA could inhibit the proliferation of RPE cells and promote the apoptosis of RPE cells, and the difference of apoptosis was statistically significant when the ATRA concentration exceeded 5 μmol/L and compared with the normal control group(P=0.027 and P=0.031, respectively). q RT-PCR results showed that ATRA could significantly inhibit the expression level of RDH5 m RNA(P<0.001) and promote the expression of MMP-2 and TGF-β2 m RNA(P=0.03 and P<0.001, respectively) in a dose-dependent manner, especially when treated with 5 μmol/L ATRA. The knockdown efficiency of RDH5 si RNA varies with different targets, among which RDH5 si RNA-435 had the highest knockdown efficiency, i.e., more than 50% lower than that of the negative control group(P=0.02). When RDH5 was knocked down for 48h, the results of q RT-PCR showed that the expressions of MMP-2 and TGF-β2 m RNA were significantly up-regulated(P<0.001).·CONCLUSION: ATRA inhibits the expression of RDH5 and promotes MMP-2 and TGF-β2, and further RDH5 knockdown significantly upregulates MMP-2 and TGF-β2. These findings suggest that RDH5 may be involved in an epithelial-mesenchymal transition of RPE cells mediated by ATRA.

Development of a Highly Sensitive Extractive Spectrophotometric Method for the Determination of Nickel(II) from Environmental Matrices Using 2-Acetylpyridine-4-methyl-3-thiosemicarbazone

Nickel(II) reacts with 2-acetylpyridine-4-methyl-3-thiosemicarbazone (APMT) and forms a yellow colored complex, which was extracted into n-hexanol from sodium acetate and acetic acid buffer at pH 6.0. The absorbance value of the Ni(II)-APMT complex was measured at different intervals of time at 375 nm to ascertain the time stability of the complex. The extraction of the complex into the solvent was instantaneous and stable for more than 72 hrs. The system obeyed Beer’s law in the concentration range of 0.235 - 2.43 μg·ml–1 of nickel(II), with an excellent linearity and a correlation coefficient of 0.999. The molar absorptivity and Sandell’s sensitivity of the extracted species were found to be 2.16 × 104 L mol–1 ·cm–1 and 0.003 μg·cm–2 at 375 nm, respectively. Hence a detailed study of the extraction of nickel(II) with APMT has been undertaken with a view to developing a rapid and sensitive extractive spectrophotometric method for the determination of nickel(II) when present alone or in the presence of diverse ions which are usually associated with nickel(II) in environmental matrices like soil and industrial effluents. Various standard alloy samples (CM 247 LC, IN 718, BCS 233, 266, 253 and 251) have been tested for the determination of nickel for the purpose of validation of the present method. The results of the proposed method are comparable with those from atomic absorption spectrometry and were found to be in good agreement.

Rosiglitazone uppresses lipopolysaccharide-induced matrix metalloproteinase-2 activity in rat aortic endothelial cells via rasMEK1/2 signaling

ix metalloproteinase(MMPs) plays a key role in the pathogenesis of chronic inflammatory disease,such as atherosclerosis.Among MMPs,MMP-2 is regarded as a major proteinase in atherosclerotic plaque lesions.Peroxisome proliferator activated receptor-gamma(PPARg) ameliorates oxidative stress and the inflammatory response.The aim of the present study was to evaluate the effect of Rosiglitazone on Lipopolysaccharide(LPS)-induced MMP-2 activation as well as its possible mechanism.LPS-induced MMP-2 activity was inhibited by Rosiglitazone(PPARg agonist) in the rat aortic endothelial cells(RAEC).LPS-induced MMP-2 activation was diminished no matter exposure to NF-kB Activation Inhibitor II(JSH-23)or Ras inhibitor,farnesylthiosalicylic acid(FTS). Further study shows that LPS-induced activation of Phospho-Rho A and Phospho-MEKl/2 were significantly inhibited by Rosiglitazone.The activation of NF-kB p65 in the nuclear extract of cells was also significantly suppressed by Rosiglitazone, moreover,the expression of NF-κB p65 was partly activated by GW9662(PPARg antagonist).NF-kB DNA binding activity was also demolished by Rosiglitazone.In summary,our data showed that PPARg agonist,Rosiglitazone suppresses LPS-activated MMP-2 secretion via Ras-MEK1/2 signaling pathways and NF-kB activation.PPARg agonist and Ras-MEK1/2 pathway may be another potential therapeutic target for the disease induced by chronic inflammation.