1.Effect of erythropoietin on Caspase-3 expression in light-injured retinal pigment epithelial cells
Chinese Journal of Tissue Engineering Research 2008;12(2):373-376
BACKGROUND: Recent studies demonstrate that erythropoietin (EPO) can protect retina from light injury, and is the mechanism related to the expression of Caspase-3 in the light-injured retinal pigment epithelium (RPE) cells. OBJECTIVE: To study the effects of EPO at different dosages on the expression of Caspase-3 in light-injured human RPE cells. DESIGN: Control observation.SETTING: Qingdao University Medical College. MATERIALS: Adult ARPE-19 cells (American Cell Culture Collection Company); DMEM/F12 mixed medium, fetal bovine serum and trypase (GIBCO Biotechnique Company); recombinant human EPO (rhEPO, Sigma Biotechnique Company); human Caspase-3 quantitative kit (Shanghai Xitang Biotechnique Co.,Ltd); Caspase-3 monoclonal antibody (American Santa Cruz Company); PV6001 immunohistochemistry kit and DAB color reagent kit (Zhongshan Biotechnology Company, Beijing).METHODS: The experiment was carried out in the Department of Pathophysiology at Qingdao University Medical College between May 2006 and January 2007. Human RPE-19 cell strain at passages 2-5 were harvested for light injury models, and the passage cells were divided into 7 groups randomly, with 4 apertures in each group:①normal control group: no light or EPO intervention;②light-injured model group: 12-hour illumination, no EPO intervention;③light-injury and EPO groups: 12-hour illumination with 10 000, 20 000 and 40 000 U/L EPO;④light-injury and 40 000 U/L EPO and AG490 group: 12-hour illumination with 40 000 U/L EPO and inhibitor of Jak2 enzyme 50 000 U/L;⑤light-injury and 40 000 U/L EPO and carbxyl-terminal modulator protein (CTMP) group: 12-hour illumination with 40 000 U/L EPO and specific inhibitor of protein kinase B enzyme 100 μmol/L.MAIN OUTCOME MEASURES: The enzyme linked immunosorbant assay (ELISA) and immunohistochemistry were used to assess the effects of rhEPO at the different doses on the expression of Caspase-3 in light-injured human RPE cells. RESULTS: Caspases-3 was not expressed in RPE cells of the normal control group and was positively expressed in the nucleus of RPE cells of the light-injured model group, showing a specific brown-yellow staining. Expression of Caspase-3 was gradually decreased in every rhEPO group with increase of EPO concentration, with the weakest expression in 40 000 U/L rhEPO group. The effects of EPO on Caspase-3 expression were strongly inhibited in light-injury+ 40 000 U/L EPO +AG490 group and the expression was positive in light-injury +40 000 U/L EPO+CTMP group, which was slightly weaker than light-injured model group. CONCLUSION: The rhEPO can reduce the expression of Caspase-3 in the light-injured human RPE cells, and one of the possible mechanisms is the inhibition of light-injured RPE cell apoptosis by the rhEPO.
2.The expression of hypoxia inducible factor 1α in embryonic and postnatal rats' retinae
Xuxia MENG ; Yingjun NIU ; Ying YANG
Chinese Journal of Ocular Fundus Diseases 2009;25(1):43-46
ObjectiveTo investigate the expression of hypoxia inducible factor 1 (HIF-1α) in rats' retinae during the embryonic and earlier postnatal period.MethodsThe retinal expression patterns of HIF-1α protein and mRNA of embryonic day 12 (E12), E16, E20, and postnatal day 1(P1) and P5 rats were determined by immunohistochemical staining and reverse transcription polymerase chain reaction (RT-PCR).ResultsHIF-1α protein was detected in the neural epithelial layer and the pigment epithelial layer at all those 5 timepoints, with higher expression in the ganglion cell layer and the inner plexiform layer, and seems limited to the ganglion cell layer when retina became more mature. Embryonic rat retina had higher expression of HIF-1α protein and mRNA than postnatal retina, the difference was significant (P<0. 01). ConclusionThe expression of HIF-1α in rats' retinae differs from embryonic to earlier postnatal stages.
4.Identification of novel inhibitors of the streptogramin group A acetyltransferase via virtual screening
Guangfeng WANG ; Niu HUANG ; Zhihong MENG ; Quanhai LIU
Acta Pharmaceutica Sinica 2007;42(1):47-53
Virginiamycin acetyltransferase D (VatD) plays a vital rule in streptogramins resistance by chemically inactivating streptogramin A. Therefore, it is desirable to discover novel small molecular weight inhibitors of VatD via state-of-the-art virtual screening techniques. This "cocktail" strategy by combining VatD inhibitor with streptogramins may provide new therapeutic opportunity for resistant bacteria infections. Structure-based virtual screening method (molecular docking) was applied to rank and score a chemical database containing 300 000 commercially available compounds against the VatD substrate binding site. Twenty six out of the 200 top scored compounds from the docking calculation were selected and submitted to the VatD enzymatic inhibition assay. The plasmid pRSET B/vatD was constructed and transformed into E.coli (trxB) host cells for over-expression, and VatD enzyme was purified and validated by showing acetyltransferase activity to Virginiamycin M1. Three out of these 26 tested compounds showed enzymatic inhibition on VatD with IC50 168.6, 91.0 and 55.2 μmol·L-1, separately. Other compounds could not be dissolved in the system and/or had little effect on the enzyme (IC50>200 μmol·L-1). To our knowledge, it is first time that small molecular weight organic compounds were identified as VatD inhibitors. It is expected that the VatD inhibitors identified at present study could serve as lead compounds for the further development of the novel therapeutic agents to overcome streptogramins resistance.
5.Intervention of basic fibroblast growth factor on apoptosis of retinal nerve cells and expression of regulatory genes in rats after retinal ischemic reperfusion
Ying ZHAO ; Yingjun NIU ; Zhanyu ZHOU ; Chunyan YUAN ; Yan MENG
Chinese Journal of Tissue Engineering Research 2006;10(13):181-183
BACKGROUND: Basic fibroblast growth factor (bFGF), a kind of polypeptide growth factor possessing multifunctional biological activities,can protect neurons and promote the growth of nerves. It has been corfirmed that bFGF has therapeutic effects on retina ischemia/reperfusion injury (RIRI).OBJECTIVE: To establish RIRI model and analyze the effects of bFGF on cellular apoptosis of retina and the expression of regulatory gene protein.DESIGN: Randomized grouping and validating trial.SETTING: Department of Ophthalmology, the Affiliated Hospital of Medical College of Qingdao University.MATERIALS: The experiment was conducted at the Research Laboratory of Pathology, Department of Ophthalmology, Medical College of Qingdao University, from April 2002 to December 2003. Twenty-eight healthy Wistar rats were enrolled in this experiment. Four rats were randomly chosen for normal control group, the left eyes of the other 24 rats were set as normal saline control group, and the right eyes were set as bFGF group.METHODS: Normal saline control group and bFGF group adopted the rat RIRI models established by transiently elevating intraocular pressure. Normal saline of 12 μL was injected into the vitreous cavity of the left eyes of the rats in normal control group. 12 μL bFGF was injected into the vitreous cavity of the right eyes of the rats in bFGF group, 4 rats once. No administration was given in normal control group. The expression of apoptotic cells was detected and apoptosis indexes were calculated with the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) method and immunohistochemical staining method at the 1st, 6th,12th, 24th,48th and 72nd hours after reperfusion and ischemia for 1 hour.MAIN OUTCOME MEASURES: ① The detection results of apoptotic cells in situ of retina tissuesat different time points after reperfusion. ②The expression of Fas and caspases-2 in retina tissues at different time points after reperfusion.RESULTS ① Comparison of apoptosis indexes of retina tissues at different time points after ischemia reperfusion: There were no apoptotic cells in the retina tissues of the rats in normal control group. As compared with those in normal saline control group, apoptosis indexes in bFGF group were significantly decreased at ischemia 1 hour and reperfusion 1, 6, 12, 24, 48and 72 hours, especially at the 12th, 24th and 48th hours after reperfusion (t =5.362-5.595, P < 0.05). ② The change of Fas expression at different time points after ischemia reperfusion: There was hardly any Fas expression in normal control group. As compared with that in normal saline control group, Fas expression in bFGF group was significantlydecreased at ischemia 1 hour and reperfusion 1, 6, 12, 24, 48 and 72 hours, especially at the 6th, 12th and 24th hours after reperfusion (t=3.954-9.327, P < 0.05). ③The changes of caspase-2 expression at different time points after ischemia reperfusion: There was no caspase-2 expression in normal control group.Compared with that in normal saline control group, the number of caspase2 positive cells in bFGF group was significantly decreased at the 6th,12th,24th, 48th and 72nd hours after ischemia for 1 hour and reperfusion (t=4.125-15.641, P < 0.05).CONCLUSION: bFGF can significantly inhibit the expression of apoptosis gene Fas and caspase-2 in the ischemia and reperfusion of retina, thus reducing cellular apoptosis of ganglion cells and exerting therapeutic effects on the ischemia and reperfusion of retina.
6.The role of somatostatin analog octreotide on gastrointestinal cancer and its influence on the serum level of insulin-like growth factor 1(IGF-1)
Aiguo ZHANG ; Jiangbin WANG ; Yuehua NIU ; Liying MENG
Cancer Research and Clinic 2008;20(4):256-258
Objective To observe the curative effects of octreotide on gastrointestinal cancer and its influenee on the serum level of IGF-1.Methods 33 patients diagnosed as advanced gastrointestinal cancer were randomized into 2 groups.15 cases in therapy group received octreotide 400μg/d subcutaneous injection or intravenous injection,other patients were taken as control.Curative effects of octreotide and serum level of IGF-1 on different time were observed before and after therapy.Results 4 cases in therapy group kept stable condition during treatment,all 18 cases in control group deteriorated gradually.The median survival time of octreotide therapy was 6.9 months,longer than that of control group(2.3 months)(P<0.05),the feeling of well being in therapy group was reported a remarkable improvement.Serum level of IGF-1 decreased obviously after octreotide injection(P<0.05),but no significant difference in control group.Conclusion Octreotide can prolong the survival duration and improve living quality of patients with advanced gastrointestinal tumors.The mechanism of antitumor is probably through suppression of IGF-1.
7.Effect of heat treatment on the viability of cultured normal human melanocytes
Jianrong NIU ; Qingqi YANG ; Rusong MENG ; Yu CHENG ; Guang ZHAO
Chinese Journal of Dermatology 2011;44(2):114-116
Objective To investigate the effect of heat treatment on the proliferation of, melanin synthesis and tyrosinase activity in cultured normal human melanocytes. Methods Normal human foreskin tissue was obtained by sterile circumcision and melanocytes were harvested by using methods for epidermal cell culture. Basic fibroblast growth factor (bFGF) was utilized as the primary mitogen to establish the culture system of normal human epidermal melanocytes. Masson-Fontana staining was proformed to identify melanocytes.Third-passage melanocytes were treated with hyperthermia at various temperatures (39 ℃, 41 ℃, 42 ℃, 43 ℃ and 45℃) for 1 hour a day for consecutive 3 days followed by the measurement of cell viability with MTT assay. The hyperthermia at optimized temperature was used to treat fourth-passage melanocytes for 1 hour a day for consecutive 3 days; subsequently, the tyrosinase activity were detected with L-Dopa as the substrate, and melanin content was determined in heat-treated and untreated (control) melanocytes. Results The hyperthermia at 42 ℃ exhibited the strongest promotive effect on the proliferation of melanocytes among these 5 hyperthermia conditions. After treatment with hyperthermia at 42 ℃ for 1 hour a day for consecutive 3 days, melanocytes showed an increment in tyrosinase activity by 36.4% and melanin synthesis by 78% compared with the untreated melanocytes (both P<0.05). Conclusions Heat treatment can enhance the proliferation of cultured human melanocytes, promote their melanin synthesis and tyrosinase activity.
9.HPLC Fingerprint study of Ziziphi Spinosae Folium
Xiang WANG ; Chuang ZHANG ; Shuaishuai FAN ; Meng WANG ; Liying NIU
Drug Evaluation Research 2017;40(6):797-800
Objective To establish a specific HPLC method and a standard fingerprint for quality control ofZiziphi Spinosae Folium.Methods The samples were separated on a Kinetex C18 column (100 mm × 2.1 mm,2.6 μm) by gradient elution at the flow rate of 300 μL/min using acetonitrile and 0.1% aqueous formic acid as the mobile phase.The column temperature was 30℃.The detection wavelength was 225 nm and the sample size was 10 μL.The fingerprint evaluation software (2012 edition) for Chinese materia medica (CMM) was used to evaluate the similarity of the 12 batches of samples.Results There were 13 characteristic peaks identified in the characteristic spectra ofZiziphi Spinosae Folium samples.Peak 6 was Rutin.The similarities of 13 batches ofZiziphi Spinosae Folium samples were proved to behigher than 0.850.Conclusion The method is available with a good reproducibility and accuraty which can control the quality standards effectively.
10.Determination of Tryptophan Based on Inner Filter Effect of FluorescentYttrium Vanadate: Europium Nanoprobes
Jianli NIU ; Yongli YU ; Yanjie CAO ; Meng WANG
Chinese Journal of Analytical Chemistry 2017;45(6):883-888
Yttrium vanadate:europium nanoprobes (YVO4∶Eu NPs) with good fluorescence properties and water solubility were synthesized by solvent thermal method.Due to the overlapping of the excitation spectrum of YVO4∶Eu NPs and the absorption spectrum of tryptophan, fluorescent internal filter effect (IFE) occurred, in which YVO4∶Eu NPs were the fluorophore and tryptophan was the absorber, leading the fluorescence of YVO4∶Eu NPs was quenched.Therefore, a new method for the determination of tryptophan was established by using fluorescent YVO4∶Eu as nanoprobes based on IFE.Some experimental parameters, such as the adding amount of YVO4∶Eu NPs, pH value of the reacting solution, and reacting time, were investigated.Under the optimum reaction conditions, the linear range of the method was 4.0×10-6-4.0×104 mol/L and the detection limit was 1.0×10-6 mol/L (3σ).The content of tryptophan in the soy sauce was determined with the recovery of 95.2% and 97.3%.This method is simple, rapid, sensitive and accurate.