OBJECTIVETo reproduce a model of heat injured KC in vitro and explore its apoptosis rate of KC due to heat injury at different temperature.

METHODSHuman KCs were cultured in vitro, and they were incubated at 37, 41, 43, 45, 48, and 51 degrees C respectively for 10 mins in water bath. Trypan blue staining and Hoechst 33258 fluorescence staining were used respectively to determine necrosis and apoptosis of KC. Rates of apoptosis and necrosis of KC were analyzed quantitatively by flow cytometer. The proliferation activity of KC after heat injury was detected by MTT test.

RESULTSThe results of trypan blue staining, Hoechst 33258 fluorescence staining, and flow cytometer demonstrated that number of apoptotic and necrotic KC increased gradually along with a rise of water bath temperature. The rates of apoptosis and necrosis of KC were respectively (12.3 +/- 3.2)% and (14.1 +/- 1.6)% at 45 degrees C, (27.7 +/- 5.1)% and (58.0 +/- 4.2)% at 48 degrees C. Rate of KC necrosis reached up to (83.0 +/- 5.3)% at 51 degrees C. Inhibition of KC growth reached a stationary phase when the injurious temperature reached 45 degrees C as observed with MTT test.

CONCLUSIONSHeat injury can induce apoptosis and growth inhibition of KC in vitro. Incubating KC at 45 degrees C for 10 mins is a good condition to reproduce a model of heat injured KC in vitro. This model may be used to study the biological character and apoptosis of KC after burn injury.

Apoptosis ; Burns ; Cell Proliferation ; Cell Survival ; Cells, Cultured ; Flow Cytometry ; Hot Temperature ; Humans ; Keratinocytes ; cytology

OBJECTIVETo study the inhibitory effects of insulin on nuclear factor-kappa B (NF-kappaB) nuclear translocation of vascular endothelial cells induced by burn serum and its correlative mechanism.

METHODSHuman umbilical vein endothelial cells (HUVECs) were cultured in vitro and divided into 5 groups: blank control group (BC, ordinary culture without any stimulation), normal serum control group (NS, cultured with nutrient solution containing 20% healthy human serum), burn serum stimulation group (BS, cultured with nutrient solution containing 20% burn human serum), burn serum+insulin treatment group (BI, cultured with nutrient solution containing 20% burn human serum and 1x10(-7) mol/L insulin), inhibitor pretreatment group [IP, pretreated with 50 micromol/L protein kinase B (Akt) specific inhibitor LY-294002, then cultured with the same medium as used in BI group 30 minutes later] according to the random number table. Six hours later, the injury and apoptosis of HUVECs was respectively observed by the scanning electron microscope and determined by the flow cytometry. Meanwhile, the phosphorylation of inhibitor kappa B-alpha (p-IkappaB-alpha) and Akt (p-Akt) in cytoplasm, and the content of NF-kappaB-p65 in nucleus were determined with Western blot.

RESULTS(1) Compared with those in BC group, HUVECs in BS group shrank obviously with irregular nuclear structure, and intercellular links jagged or vanished. Slight change was observed in HUVECs structure in NS and BI groups, with the cell ductility and nuclear structure much better than those in BS group. (2) The apoptosis rates of HUVECs in BS group [(28.5+/-2.3)%], BI group [(22.3+/-1.8)%], and IP group [(29.7+/-2.4)%] were all obviously higher than that in BC group [(15.7+/-2.2)%, F=14.288, P<0.05 or P<0.01]. There was no significant statistical difference between NS group [(17.0+/-2.5)%] and BC group in apoptosis rate (F=14.288, P>0.05). The apoptosis rate of HUVECs in BI group was obviously lower than that in BS group (F=14.288, P<0.05). (3) Compared with those in BC group, the protein expressions of p-IkappaB-alpha in cytoplasm and NF-kappaB-p65 in nucleus were up-regulated, and the protein expression of p-Akt in cytoplasm was down-regulated in BS and IP groups. The expression levels of the three proteins in NS and BI groups were close to those in BC group.

CONCLUSIONSInsulin could inhibit the IkappaB phosphorylation, and then restrict NF-kappaB nuclear translocation and improve the vascular endothelial cells function accordingly through regulating phosphatidylinositol 3 kinase/Akt pathway.

Apoptosis ; Burns ; blood ; Cells, Cultured ; Endothelial Cells ; metabolism ; Endothelium, Vascular ; cytology ; metabolism ; Humans ; I-kappa B Proteins ; metabolism ; Insulin ; pharmacology ; NF-kappa B ; metabolism ; Phosphorylation ; Serum ; metabolism ; Umbilical Veins ; cytology

BACKGROUNDCystic echinococcosis due to Echinococcus granulosus (E. granulosus) is one of the most important chronic helminthic diseases, especially in sheep/cattle-raising regions. The larval stage of the parasite forms a cyst that grows in the liver, lung, or other organs of the host. To ensure a long life in the host tissues, the parasite establishes complex inter-cellular communication systems between its host to allow its differentiation toward each larval stage. Recent studies have reported that this communication is associated with the extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase cascade in helminth parasites, and in particular that these protein kinases might serve as effective targets for a novel chemotherapy for cystic echinococcosis. The aim of the present study investigated the biological function of a novel ERK ortholog from E. granulosus, EgERK.

METHODSDNA encoding EgERK was isolated from protoscolices of E. granulosus and analyzed using the LA Taq polymerase chain reaction (PCR) approach and bioinformatics. Reverse transcription PCR (RT-PCR) was used to determine the transcription level of the gene at two different larval tissues. Western blotting was used to detect levels of EgERK protein. The expression profile of EgERK in protoscolices was examined by immunofluorescence.

RESULTSWe cloned the entire Egerk genomic locus from E. granulosus. In addition, two alternatively spliced transcripts of Egerk, Egerk-A, and Egerk-B were identified. Egerk-A was found to constitutively expressed at the transcriptional and protein levels in two different larval tissues (cyst membranes and protoscolices). Egerk-A was expressed in the tegumental structures, hooklets, and suckers and in the tissue surrounding the rostellum of E. granulosus protoscolices.

CONCLUSIONSWe have cloned the genomic DNA of a novel ERK ortholog from E. granulosus, EgERK (GenBank ID HQ585923), and found that it is constitutively expressed in cyst membrane and protoscolex. These findings will be useful in further study of the biological functions of the gene in the growth and development of Echinococcus and will contribute to research on novel anti-echinococcosis drug targets.

Animals ; Blotting, Western ; Computational Biology ; DNA, Helminth ; genetics ; Echinococcus granulosus ; enzymology ; genetics ; Genome, Helminth ; genetics ; Helminth Proteins ; genetics ; metabolism ; Polymerase Chain Reaction