AIM:The 50-Hz magnetic field (MF) is a potential health-risk factor.Its effects on the cardiovascular system have not been fully investigated .This study was conducted to explore the effects of long-term exposure to 50-Hz MF on the cardiovascular system . METHODS:In the study , an exposure system was constructed and the distribution of 50-Hz MF was detected .Sixty-four Sprague-Dawley (SD) rats were exposed to 50-Hz MF at 100 μT for 24 weeks, 20 hours per day, while another 64 rats were sham exposed. During the exposure, blood pressure was measured every 4 weeks, and 24 weeks later, echocardiography, cardiac catheterisation and electrocardiography were performed .Moreover , heart and body weight were recorded , while haematoxylin-eosin staining and real-time PCR were conducted .RESULTS:The results showed that compared with the sham group , exposure to 50-Hz MF did not exert any effect on blood pressure, pulse rate, heart rate and cardiac rhythm.Further, echocardiography and cardiac catheterisation showed that there were no significant differences in the cardiac morphology and haemodynamics .In addition , histopathological examination showed that 50-Hz MF exposure had no effect on the structure of hearts .Finally, the expression of the cardiac hypertrophic relative genes did not show any significant differences between 50-Hz MF exposure group and the sham group .CONCLUSION: Taken together , in SD rats, exposure to 50-Hz/100-μT MF for 24 weeks did not show any obvious effects on the cardiovascular system .

Objective To investigate the expressions of matrix metalloproteinases(MMPs) in Kashin-Beck disease(KBD) cartilage as well as in a KBD rat model of T-2 toxin poisoning under selenium deficient conditions, and to investigate the effect of T-2 toxin on MMP-13 expression in human chondrocytes in vitro in order to determine a possible mechanism underlying KBD. Methods Samples of articular cartilage were divided into 2 groups:controls(samples from 5 normal children, traffic accident or operation), and KBD(samples from 5 children with KBD, auctopsy). Thirty-two Sprague-Dawley rats were divided into two groups by body weight using random number table: normal diet group(n = 16) and selenium-deficient diet group(n=16). The selenium level in normal diet was 101.500μg/kg, and in selenium-deficient diet was 1.118μg/kg. Rats were fed for 4 weeks with selenium-deficient or normal diet, respectively. After successful build up of the low selenium rat model, normal diet group was then subdivided into 2 sub-groups: normal group(n = 8) and normal diet plus low T-2 toxin group(n = 8);and selenium-deficient diet group was also subdivided into 2 sub-groups: selenium-deficient group ( n = 8 ) and selenium-deficient diet plus T-2 toxin group ( n = 8 ) . T-2 toxin of 100 μg·kg-1·d-1 was administered by intragastric administration for 30 days. Then the rats were sacrificed, and their knee joints were processed for histopathological evaluation. MMP-1 and MMP-13 locations in cartilages were performed by inmmunohistochemistry. Human chondrocytes C28/I2 were cultured in vitro. The experiment was divided into 4 groups: empty vector plasmid group, MMP-13 promoter plasmid group, MMP-13 promoter plasmid plus 20 μg/L T-2 toxin group and MMP-13 promoter plasmid plus 40 μg/L T-2 toxin group. MMP-13-luciferase reporter plasmid and vector plasmid were transiently transfected into C28/I2 cells for 24 hours, and then treated with 20 - 40 μg/L T-2 toxin for 24 hours. Transactivation of human MMP-13 promoter was analyzed using luciferase reporter constructs containing sequences spanning-1602 to+20 bp in C28/I2 chondrocytes. Results The percentages of chondrocytes staining for MMP-1 in the superficial and middle zones of KBD samples [(29.73 ± 10.12)%, (28.27 ± 0.91)%] were significantly higher than those of controls[(2.47 ± 0.11)%, (0.00 ± 0.00)%, all P < 0.05]. The percentages of chondrocytes staining for MMP-13 in the superficial and middle zones of KBD samples [(13.21 ± 4.32)%, (41.85 ± 6.32)%] were significantly higher than those of controls[(5.72 ± 0.31)%, (0.00 ± 0.00)%, all P<0.05]. The percentages of chondrocytes staining for MMP-13 in the superficial and middle zones of rats fed with selenium-deficient diet plus T-2 toxin group[(13.21 ± 4.32)%, (61.85 ± 8.68)%] were significantly higher than those of the normal and selenium-deficient groups[(2.43 ± 0.22)%, (5.89 ± 0.69)%, (3.03 ± 0.29)%, (25.99 ± 0.57)%, all P < 0.05]. Moreover, T-2 toxin activated the MMP-13 promoter detected with luciferase reporter assays in C28/I2 cells. The luciferase activities in MMP-13 promoter plasmid plus 20 μg/L T-2 toxin group and MMP-13 promoter plasmid plus 40μg/L T-2 toxin group(0.082 78 ± 0.008 40, 0.103 35 ± 0.013 19) were significantly higher than those in empty vector plasmid group and MMP-13 promoter plasmid group(0.024 19 ± 0.000 96, 0.040 32 ± 0.003 56, all P < 0.05). Conclusions These data suggest that T-2 toxin induces cartilage matrix degradation through up-regulation of MMP-13 promoter expression. Increased MMPs staining intensity in KBD cartilage and the rat KBD model of T-2 toxin poisoning under selenium deficient conditions suggest that matrix degradation appear to be driven by MMPs activity.

OBJECTIVE:To adopt gel method for the determination of bacterial endotoxin in Fat emulsion(10%)/amino acid (15)/glucose (20%) injection. METHODS:According to the gel method in term ofbacterial endotoxin test methodin Chinese Pharmacopeia(2015 edition),the maximal valid dilution(MVD)of samples were determined through interference test and the vali-dated. The results were compared with chromogenic method. RESULTS:In gel method,the interference to agglutination reaction of TAL and bacterial endotoxin can be excluded when samples were diluted 24 times or less. In chromogenic method,the samples should be diluted 76 times or less. CONCLUSIONS:Gel method can be used for bacterial endotoxin test of Fat emulsion(10%)/amino acid(15)/glucose(20%)injection.

Bone marrow-derived mesenchymal stem cells (BMSCs) for repairing damaged heart tissue are a new kind of important treatment options because of their potential to differentiate into cardiomyocytes. We in this experiment investigated the effect of different electrical stimulation time on the expression of myocardial specificity gene and protein in rat bone marrow mesenchymal stem cells (rBMSCs) in vitro. The rBMSCs of second or third generation were randomly divided into three groups, i.e, electrical stimulation (ES) group, 5-Azacytidine (5-Aza) group and the control group. The rBMSCs in the ES groups with complete medium were exposed to 2 V, 2 Hz, 5 ms electrical stimulation for 0. 5 h, 2 h, 4 h, and 6 h respectively every day for 10 days. Those in the 5-Aza group were induced by 5-Aza (10 μmol/L) for 24 h, and then cultured with complete medium for 10 days. Those in the control group were only cultured with complete medium, without any treatment, for 10 days. The rBMSCs' morphological feature in each group was observed with inverted phase microscope. The mRNA expression of myocyte-specific enhancer factor 2C (MEF-2C) and connexin 43 (Cx43) were examined with Real-Time quantitative PCR and the protein expression of MEF-2C, Cx43 were detected with Western Blot method. The results showed that the mRNA expression level of the MEF-2C, Cx43 and the protein expression level of MEF-2C, Cx43 were significantly higher in the ES group and 5-Aza group than those in the relative control group (P < 0.05). It suggests that electrical stimulation could play a part of role in the induction of the rBMSCs to differentiate into the cariomyocyte-like cells in vitro and the effectiveness of the electrical stimulation with 2 h/d had the best in our experiment. But the mechanism how electrical stimulation promotes the differentiation of rBMSC into cardiomyocyte is still unclear.
Animals ; Biomarkers ; metabolism ; Cell Differentiation ; Cells, Cultured ; Connexin 43 ; metabolism ; Electric Stimulation ; MEF2 Transcription Factors ; metabolism ; Mesenchymal Stromal Cells ; cytology ; metabolism ; Myocytes, Cardiac ; cytology ; RNA, Messenger ; metabolism ; Rats ; Rats, Sprague-Dawley

Objective To investigate the death of chondrocytes in rats which feed with T-2 toxin under selenium (Se) deficient conditions.Methods Thirty two healthy male SD rats were divided into two groups by weight which were normal diet group and Se deficiency diet group,16 rats in each group.Rats in normal diet group were fed with Se 101.5 μg/kg diet,and rats in Se deficiency diet group were fed with Se 1.1 μg/kg diet for 30 d.Normal diet group was divided into control group and T-2 toxin group,and Se deliciency diet group was randomly divided into Se-deficiency group and Se-deficiency plus T-2 toxin group,8 rats in each group.After that,rats in T-2 toxin and Se-deficiency plus T-2 toxin groups were administrated intragastrically with T-2 toxin (100 μg/kg) everyday for 30 d.Rats were put to death,the left knee was taken and stained with hematoxylin-eosin and SafraninFast green,pathological changes of rat's knee joint cartilage were observed under light microscopy,expression levels of active caspase-3 and receptor interacting protein 3 (RIP3) in rat's articular cartilage cells were determined via the immunohistochemical method.The apoptosis was also detected by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay (TUNEL).Results Red ghost outlines of chondrocyte and multiple chondral cell clusters surrounded the non-cell areas in deep zone of articular cartilage of knee joint stained with hematoxylineosin were seen in Se-deficiency plus T-2 toxin group under light microscope.In the superficial zone of cartilage,the positive percent of TUNEL and active caspase-3 in Se-deficiency plus T-2 toxin group was higher than those of control group,Se-deficiency group and T-2 toxin group [(7.47-± 0.34)％ vs (4.68 ± 0.54)％,(2.67-± 0.64)％,(2.56 ±0.54)％;(4.75 ± 0.67)％ vs (1.24 ± 0.25)％,(0.00 ± 0.00)％,(0.00 ± 0.00)％,P ＜ 0.05].In the middle zone of cartilage,the positive percent of TUNEL,active caspase-3 and RIP3 in Se-deficiency plus T-2 toxin group was significantly higher than those of control group,T-2 toxin group and Se-deficiency group [(72.06 ± 6.15)％ vs (16.10 ± 3.00)％,(19.57 ± 3.49)％,(19.33 ± 5.19)％;(51.13 ± 4.18)％ vs (10.97-± 3.01)％,(15.36 ± 4.37)％,(15.23 ± 3.13)％;(25.91 ± 13.39)％ vs (1.59 ± 1.14)％,(4.32 ± 2.91)％,(7.50 ± 5.00)％,P ＜ 0.05].The positive percents of TUNEL,active caspase-3 and RIP3 were not significantly different in the deep zone (P ＞ 0.05).Conclusion The death of the middle zone in the rat cartilage induced by T-2 toxin under selenium deficient conditions isapoptosis and necroptosis.

OBJECTIVE:To study the chemical constituents of 70％ ethanol extract of Breynia fruticosa.METHODS:The 70％ ethanol extract of B.fruticosa were isolated and purified by D101 macroporous resin,silica gel column chromatography,RP-silica gel column chromatography,Sephadex LH-20 gel column chromatography,preparative HPLC.The structure of compound was analyzed and identified according to physicochemical characters and spectral data.RESULTS:10 compounds were separated from 70％ ethanol extract of B.fruticosa,such as Luteolin (1),Quercetin (2),Kaempferol (3),Tiliroside (4),(+)-Lyoniresinol (5),(+)-Isolariciresinol (6),(+)-Nortrachelogenin (7),(+)-Syringaresinol (8),Icariol A2 (9),5,5'-Dimethoxy-7-oxolariciresinol (10),respectively.CONCLUSIONS:Ten compounds are isolated from this plant for the first time.The study play the found for quality evaluation of 70 ％ ethanol extract of B.fruticosa.

Objective: To investigate the effects of lactoprotein iron chelates on rats with iron deficiency anaemia (IDA), so as to provide insights into developing and utilizing novel iron supplements. Methods: Seventy weaning female SPF-graded rats of the SD strain were randomly divided into the control group (A), model group (B), ferrous sulfate group (C), lactoferrin group (D), lactoferrin iron chelate group (E), Casein oligopeptide iron chelate group (F) and whey protein oligopeptide iron chelate group (G), with 10 rats in each group. The rats in group A were fed with normal diet, and the others were fed with poor iron diet for IDA modeling. The corresponding interventions were given by intragastric administration once a day. The iron ion concentrations of group C, E, F and G were 2.0 mg/kg, and the protein and oligopeptide concentrations of group D, E, F and G were 2 000 mg/kg. Body weight and hemoglobin of rats were measured weekly during 21-day intervention. At the end, peripheral blood samples were collected, and blood routine, iron metabolism and liver function indicators were determined. Results: After the intervention, among blood routine indicators, the rats in group C, E, F and G showed elevated hemoglobin, red blood cell, mean corpuscular volume and hematocrit, and decreased free protoporphyrin and mean corpuscular hemoglobin concentration when compared with the rats in group B (all P<0.05); among iron metabolism indicators, the rats in group C, E and G showed elevated serum ferritin, the rats in group C, E, F and G showed elevated serum iron, the rats in group C, D, E, F and G showed decreased unsaturated iron binding capacity and total iron binding capacity when compared with the rats in group B (all P<0.05); among liver function indicators, the rats in group E and G showed decreased alanine transaminase when compared with the rats in group B (both P<0.05). Conclusions Lactoprotein alone could not completely improve IDA in rats compared with traditional iron supplement (ferrous sulfate). Lactoprotein iron chelate, especially whey protein oligopeptide iron chelate, could significantly improve IDA, iron reserve and liver function damage in rats.

Objective:To evaluate the effect of propofol on neuronal activity in medial prefrontal cortex (mPFC) during social behavior in sleep-deprived rats.Methods:Sixty SPF healthy male Sprague-Dawley rats, aged 8 weeks, weighing 200-250 g, were divided into 3 groups ( n=20 each) using a random number table method: control group (group Con), chronic sleep deprivation plus natural sleep group (group CSD+ NS), and chronic sleep deprivation plus propofol group (CSD+ Pro). Sleep deprivation model was developed by the modified multiple platform method, and the rats were placed in the sleep-deprivation tank for 20 h a day (14: 00-10: 00) and allowed to sleep naturally for 4 h (10: 00-14: 00) a day for 28 consecutive days.Propofol 40 mg/kg was intraperitoneally injected after sleep deprivation for 28 consecutive days in group CSD+ Pro, while the equal volume of 10% fat emulsion was given instead in group C and group CSD+ NS.Electroencephalographic recordings in cerebral cortical regions were performed on the days 1st, 14th and 28th after sleep deprivation.The apoptotic neurons in mPFC were detected using TUNEL method after the end of sleep deprivation, and the apoptosis index was calculated.A three chamber sociability test was used to detect the social behavior of rats, and local field potential signals in mPFC were collected. Results:Compared with group Con, the percentage of rapid eye movement sleep was significantly increased, the sniffing time preference coefficients in the 2 stages were reduced, the percentage of the β waves and θ waves-band power in mPFC during the social sniffing process was decreased, and the apoptosis index of neurons in mPFC was increased in group CSD+ NS ( P<0.05). Compared with group CSD+ NS, the percentage of rapid eye movement sleep was significantly increased, the sniffing time preference coefficient in the 2 stages was increased, and the percentage of β waves and θ waves-band power in mPFC during the social sniffing process was increased, and the apoptosis index of neurons in mPFC was decreased in group CSD+ Pro ( P<0.05). Conclusions:Propofol inhibits the apoptosis in neurons in mPFC and increases β and θ waves in the mPFC during social interaction after sleep deprivation in sleep-deprived rats, which is helpful in improving sleep deprivation-induced social disorder.

Small cell lung cancer (SCLC) is a rapidly developing malignant tumor, which is highly heterogeneous and prone to drug resistance, and the prognosis is usually poor. Poly ADP-ribose polymerase (PARP) inhibitors target the DNA damage response pathway, preventing DNA repair, thereby exerting anti-tumor effects. Currently, PARP inhibitors are used as monotherapy or in combination with DNA-damaging agents or immune checkpoint inhibitors in the treatment of SCLC. Although the current research results are limited, it can be seen that PARP inhibitors may be a breakthrough in the targeted therapy of SCLC.

Objective:To evaluate the effect of propofol on parvalbumin (PV) neurons in the medical prefrontal cortex(mPFC)of rats with social behavior disorders induced by chronic sleep deprivation.Methods:Forty-two SPF male Sprague-Dawley rats, aged 8 weeks, weighing 200-250 g, were divided into 3 groups ( n=14 each) using a random number table method: control group (group Con), chronic sleep deprivation plus natural sleep group (group CSD+ NS), and chronic sleep deprivation plus propofol group (group CSD+ Pro). Sleep deprivation model was established by the modified multiple platform method, the rats were placed in the sleep-deprivation tank for 20 h a day (14: 00-10: 00), and allowed to sleep naturally for 4 h (10: 00-14: 00) a day for 28 consecutive days. Propofol 40 mg/kg was intraperitoneally injected for 28 consecutive days after sleep deprivation in CSD+ Pro group. While the equal volume of 10% fat emulsion was given in Con and CSD+ NS groups. After the end of sleep deprivation, a three-box social experiment was used to detect the social behavior of rats, and the number of the PV positive cells and density of the perineuronal network (PNN) in the mPFC area were measured by immunofluorescence. Results:Compared with group Con, the pertentage of rapid eye movement sleep and sniffing time preference coefficients for the strange rat 1 in the first stage and for the strange rat 2 in the second stage were significantly decreased, and the number of the PV positive cells and density of PNN in the mPFC area were decreased in group CSD+ NS ( P<0.05). Compared with group CSD+ NS, the sniffing time preference coefficients for the strange rat 1 in the first stage and for the strange rat 2 in the second stage were significantly increased, the number of the PV positive cells and density of PNN in the mPFC area were increased( P<0.05), and no significant change was found in the percentage of the rapid eye movement sleep in group CSD+ Pro. Conclusions:Propofol probably increases the number and function of PV neurons in the mPFC and ameliorates sleep deprivation-induced social behavior disorders in sleep-deprived rats.