Pb induces the release of CXCL10 and CCL2 chemokines via mtROS/NF-κB activation in BV-2 cells.

Lead (Pb), a well-known environmental pollutant, could cause damage of microglia, the resident macrophages vitally regulating inflammation in brain. Previous studies have found that Pb exposure induces typical pro-inflammatory factors release, such as tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß), but what effects of Pb treatment below the dose causing these factors release are unknown. Thus, cytokines assay was performed to identify the factors released from Pb-treated BV-2 cells at 2.5 µM, causing no effects on TNF-α, IL-1ß, and IL-6 release and cell death. Cytokines assay identified low doses of Pb exposure mainly induce an increase in specific chemokines, including CXCL10, CCL2, and CXCL2, which were confirmed by ELISA. Subsequent assessment found Pb could damage mitochondria function and generate mitochondrial reactive oxygen species (mtROS), and Mito TEMPO, a specific inhibitor of mtROS, suppressed Pb-caused upregulation of CXCL10 and CCL2, but not CXCL2. Finally, we determined that mtROS mediated Pb-induced activation of NF-κB pathway, as Mito TEMPO treatment inhibited P-p65/p65 escalation during Pb treatment. Inhibition of NF-κB pathway by Bay11-7821 suppressed the release of CXCL10 and CCL2. Collectively, low dose of Pb induces the release of CXCL10 and CCL2 chemokines, but not TNF-α and IL-1ß, via mtROS/NF-κB activation in BV-2 cells.

Perspective of Calcium Imaging Technology Applied to Acupuncture Research / 中国结合医学杂志

Acupuncture, a therapeutic treatment defined as the insertion of needles into the body at specific points (ie, acupoints), has growing in popularity world-wide to treat various diseases effectively, especially acute and chronic pain. In parallel, interest in the physiological mechanisms underlying acupuncture analgesia, particularly the neural mechanisms have been increasing. Over the past decades, our understanding of how the central nervous system and peripheral nervous system process signals induced by acupuncture has developed rapidly by using electrophysiological methods. However, with the development of neuroscience, electrophysiology is being challenged by calcium imaging in view field, neuron population and visualization in vivo. Owing to the outstanding spatial resolution, the novel imaging approaches provide opportunities to enrich our knowledge about the neurophysiological mechanisms of acupuncture analgesia at subcellular, cellular, and circuit levels in combination with new labeling, genetic and circuit tracing techniques. Therefore, this review will introduce the principle and the method of calcium imaging applied to acupuncture research. We will also review the current findings in pain research using calcium imaging from in vitro to in vivo experiments and discuss the potential methodological considerations in studying acupuncture analgesia.

Lead exposure represses mitochondrial metabolism by activation of heme-binding protein BACH1 in differentiated SH-SY5Y cell.

Exposure to lead (Pb), a known toxin causing developmental neurotoxicity, can impair neurogenesis and oxidative phosphorylation (OXPHOS), but the mechanism is not clarified. In the current study, we aim to explore the effects of Pb on the differentiation of SH-SY5Y cells and investigate the role of heme and heme-binding protein BACH1 during differentiation. We found that Pb exposure caused a shift from OXPHOS to glycolysis, resulting in neurogenesis impairment by decreasing neurite growth and downregulation of PSD95 and Synapsin-1 in differentiated SH-SY5Y cells. Heme reduction mediated this mitochondria metabolism repression caused by Pb depending on BACH1 activation. Hemin supplement alleviated Pb-induced OXPHOS damage and adenosine triphosphate (ATP) reduction in differentiated SH-SY5Y cells, and further protected for Pb-induced damage of synapse. Heme binding factor BACH1 was negatively regulated by heme content and BACH1 knockout rescued the Pb-induced transcription and expression decline of genes related to OXPHOS and abrogated Pb-induced growth inhibition of axon promotion and synapse formation. Collectively, the present study demonstrates that heme deficiency mediates OXPHOS damage caused by Pb through BACH1 activation, resulting in neurogenesis impairment.

Referred Somatic Hyperalgesia Mediates Cardiac Regulation by the Activation of Sympathetic Nerves in a Rat Model of Myocardial Ischemia / 神经科学通报·英文版

Myocardial ischemia (MI) causes somatic referred pain and sympathetic hyperactivity, and the role of sensory inputs from referred areas in cardiac function and sympathetic hyperactivity remain unclear. Here, in a rat model, we showed that MI not only led to referred mechanical hypersensitivity on the forelimbs and upper back, but also elicited sympathetic sprouting in the skin of the referred area and C8-T6 dorsal root ganglia, and increased cardiac sympathetic tone, indicating sympathetic-sensory coupling. Moreover, intensifying referred hyperalgesic inputs with noxious mechanical, thermal, and electro-stimulation (ES) of the forearm augmented sympathetic hyperactivity and regulated cardiac function, whereas deafferentation of the left brachial plexus diminished sympathoexcitation. Intradermal injection of the α2 adrenoceptor (α2AR) antagonist yohimbine and agonist dexmedetomidine in the forearm attenuated the cardiac adjustment by ES. Overall, these findings suggest that sensory inputs from the referred pain area contribute to cardiac functional adjustment via peripheral α2AR-mediated sympathetic-sensory coupling.

Systematic review and Meta-analysis of the efficacy of Apatinib and Tegafur in the treatment of colonic neoplasms / 国际外科学杂志

Objective:To conduct a systematic review and Meta-analysis of the efficacy and safety of Apatinib and tegafur in colonic cancer.Methods:With "Apatinib" "Tegafur" "Colonic cancer" as keywords, PubMed, Embase, Web of Science, Cochrane Library, WanFang Data, VIP, CNKI and CBM were searched from inception to December 2020 to collect randomized controlled trail about treatment for colonic cancer with Apatinib and Tegafur. Evaluated the portion remission and stable duration and progression-free survival. Meta-analysis was performed by using RevMan 5.3 software.Results:Meta-analysis showed that in colonic cancer patients, the portion remission and stable duration, tumor progression of Apatinib were not inferior to those of Tegafur ( RR=1.10, 95% CI: 0.71-1.71, P=0.640; RR=0.51, 95% CI: 0.28-1.32, P=0.205). But for progression-free survival, Apatinib was superior to Tegafur in overall patients( SMD=0.90, 95% CI: 0.42-1.37, P<0.000 1). Conclusion:In the treatment of colon cancer, compared with Tegafur, Apatinib can effectively improve the progression-free survival and has better overall survival.

Application progress of smart glasses for triage during mass casualty incident / 中华危重病急救医学

In mass casualty incidents (MCI), the number of casualties can far exceed the capacity of medical emergency units to treat and transport in a very short period of time. A rapid MCI triage according to the severity of their injuries, can not only effectively use limited medical resources, but also improve the survival rate of injured patients. With the emergence of artificial intelligence (AI) and augmented reality (AR), smart glasses have been developed and used in different scenarios, and have achieved remarkable results in the medical field. This article focuses on the role and advantages of smart glasses in the triage of MCI, while proposing the problems in the application of smart glasses. At the same time, we elaborate on the development status of smart glasses in the triage, and discuss the application trend and development direction of smart glasses in the triage of pre-hospital injuries.

Smoking and SARS-CoV-2 Impair Dendritic Cells and Regulate DC-SIGN Expression in Tissues

The current spreading novel coronavirus SARS-CoV-2 is highly infectious and pathogenic. In this study, we screened the gene expression of three SARS-CoV-2 host receptors (ACE2, DC-SIGN and L-SIGN) and DC status in bulk and single cell transcriptomic datasets of upper airway, lung or blood of smokers, non-smokers and COVID-19 patients. We found smoking increased DC-SIGN gene expression and inhibited DC maturation and its ability of T cell stimulation. In COVID-19, DC-SIGN gene expression was interestingly decreased in lung DCs but increased in blood DCs. Strikingly, DCs shifted from cDCs to pDCs in COVID-19, but the shift was trapped in an immature stage (CD22+ or ANXA1+ DC) with MHCII downregulation in severe cases. This observation indicates that DCs in severe cases stimulate innate immune responses but fail to specifically recognize SARS-CoV-2. Our study provides insights into smoking effect on COVID-19 risk and the profound modulation of DC function in severe COVID-19. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=139 SRC="FIGDIR/small/20245316v1_ufig1.gif" ALT="Figure 1"> View larger version (59K): org.highwire.dtl.DTLVardef@11a509borg.highwire.dtl.DTLVardef@a1faeforg.highwire.dtl.DTLVardef@619bb4org.highwire.dtl.DTLVardef@357bf5_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsSmoking upregulates the expression of ACE2 and CD209 and inhibits DC maturation in lungs. SARS-CoV-2 modulates the DCs proportion and CD209 expression differently in lung and blood. Severe infection is characterized by DCs less capable of maturation, antigen presentation and MHCII expression. DCs shift from cDCs to pDCs with SARS-CoV-2 infection but are trapped in an immature stage in severe cases.

Treatment with metformin and sorafenib alleviates endometrial hyperplasia in polycystic ovary syndrome by promoting apoptosis via synergically regulating autophagy.

This study aimed to investigate the molecular mechanisms underlying the roles of metformin (MET) and Sorafenib (SOR) in the treatment of endometrial hyperplasia (EH) in polycystic ovary syndrome (PCOS). Effects of MET and SOR on the area of endometrium and myometrium were detected. Western blot analysis and immunohistochemistry assays were carried out to detect the levels of mammalian target of rapamycin complex 1 (mTORC1), mTORC2, LC3-II, P62, and Caspase-3 in rats and cultured cells. Furthermore, cell counting kit-8 assay and flow cytometry analysis was carried out to determine the apoptotic profiles of treated cells. MET and SOR could apparently decrease the areas of endometrium and myometrium in PCOS. MET notably enhanced the expression of LC3-II and Caspase-3 in PCOS while substantially reducing the level of mTORC1 and P62. Similarly, SOR also enhanced the expression of LC3-II and Caspase-3 in PCOS while substantially reducing the level of mTORC2 and P62. Treatment with MET and SOR significantly inhibited the proliferation of HCC-94 and HEC-1-A cells while promoting their apoptosis by upregulating the expression of Caspase-3. In cells treated with MET, the expression of mTORC1 and LC3-II was upregulated while the expression of P62 was downregulated. Similarly, in cells treated with SOR, the expression of mTORC2 and LC3-II was also upregulated while the expression of P62 was also downregulated. Furthermore, MET showed no effect on mTORC2 expression, while SOR showed no effect on mTORC1 expression. In this study, we suggested that MET and SOR alleviated the risk of EH in PCOS via the mTORC1/autophagy/apoptosis axis and mTORC2/autophagy/apoptosis axis, respectively.

Electroacupuncture at "Neiguan"(PC6) decreased cardiac sympathetic hyperactivity and improved cardiac function in chronic myocardial ischemia model rats / 针刺研究

OBJECTIVE: To investigate the autonomic nervous mechanism of acupuncture therapy in the treatment of ischemic cardiomyopathy by observing the influence of electroacupuncture (EA) at "Neiguan"(PC6) on the superior cervical cardiac nerve activity and cardiac function in chronic myocardial ischemia (CMI) rats. METHODS: Male SD rats were randomly divided into control, model and EA groups (n＝8 in each group). The CMI model was established by ligating the anterior descending branch of the left coronary artery. EA (15 Hz, 1.5 mA) was applied to bilateral PC6 for 20 min, once a day for 28 consecutive days. Cardiac sympathetic nerve electrical activities (CSNEA), electrocardiogram (ECG) of the standard limb lead Ⅱ and ultrasonic cardiogram (UCG) were recorded for observing changes of ST segment height, left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS)．. RESULTS: The CSNEA was significantly increased(P<0.001), and the hight of ECG-STⅡ， LVEF and LVFS were considerably decreased in the model group relevant to the control group (P<0.01, P<0.001), while after the intervention, modeling induced increase of CSNEA and decrease of ECG-STⅡ， LVEF and LVFS were obviously suppressed in the EA group in comparison with the model group (P<0.01, P<0.05, P<0.001). CONCLUSION: EA of PC6 can improve cardiac function and myocardial ischemia in CMI rats, which is possibly related to its effect in decreasing cardiac sympathetic hyperactivity.

The long non-coding RNA PTTG3P promotes growth and metastasis of cervical cancer through PTTG1.

The outgrowth and metastasis of cervical cancer (CC) contribute to its malignancy. Pituitary Tumor Transforming Gene 1 (PTTG1) is upregulated in many types of cancer, and enhances tumor cell growth and metastasis. However, the activation and regulation of PTTG1 in CC, especially by its pseudogene PTTG3P, have not been shown. Here, we detected significantly higher levels of PTTG1 and PTTG3P in the resected CC tissue, compared to the paired adjacent normal cervical tissue. Interestingly, the PTTG3P levels positively correlated with the PTTG1 levels. High PTTG3P levels were associated with poor patients' survival. In vitro, PTTG1 were increased by PTTG3P overexpression, but was inhibited by PTTG3P depletion in CC cells. However, PTTG3P levels were not altered by modulation of PTTG1 in CC cells, suggesting that PTTG3P is upstream of PTTG1. Moreover, PTTG3P increased CC cell growth, likely through CCNB1-mediated increase in cell proliferation, rather than through decrease in cell apoptosis. Furthermore, PTTG3P increased CC cell invasiveness, likely through upregulation of SNAIL and downregulation of E-cadherin. Our work thus suggests that PTTG3P may promote growth and metastasis of CC through PTTG1.

Correlation between referred pain distribution and acupoint sensitization in patients with intestinal diseases / 中国针灸

OBJECTIVE@#To observe the correlation between referred pain distribution and acupoint sensitization in patients with intestinal diseases.@*METHODS@#In clinical research, 443 patients from 8 hospitals were recruited, including the outpatients and inpatients of Crohn's disease (=143), ulcerative colitis (=108), chronic appendicitis (=87) and other intestinal diseases (=105). The site with tenderness on the body surface and the morphological changes of local skin were observed and recorded in the patients. Using a sensory tenderness instrument, the pain threshold at the sensitization point was measured in 60 patients with ulcerative colitis. In animal experiment, SD rats were used and divided into a enteritis group (=8), in which the enteritis model were established, and a control group (=3), in which no any intervention was given. After the injection of Evans blue (EB) at caudal vein, the blue exudation points on the body surface were observed and the distribution rule was analyzed statistically.@*RESULTS@#The referred pain on the body surface in the patients with intestinal diseases was mainly located in the lower abdomen (93.9%, 416/443), the lumbar region (70.9%, 314/443) and the lower legs (33.0%, 146/443). The diameter of tenderness region was 1.5 to 2.5 cm. Compared with the region without sensitization, the pain threshold of the sensitization point in the patients with ulcerative colitis was reduced significantly (<0.001). The referred pain on the body surface in the patients with appendicitis was located in the right lower abdomen (97.7%, 85/87), the waist and back (54.0%, 47/87) and the right lower limbs on the medial side (71.3%, 62/87). The tenderness region was 1 to 2 cm in diameter and was irregular in form. After modeling of enteritis in the rats, the EB exudation points were visible from T to L.@*CONCLUSION@#Intestinal diseases induce referred pain on the body surface where is the same as or adjacent to the location of the spinal segment corresponding to the affected intestinal section. These sensitization regions are related to the locations of acupoints.

Inner Surface-Functionalized Graphene Aerogel Microgranules with Static Microwave Attenuation and Dynamic Infrared Shielding.

Bulk graphene aerogels with high electrical conductivity, ultralow density, and high specific surface area have attracted significant attention because of their fascinating performances in energy storage, catalysis, absorption, sensor, electromagnetic shielding, etc. However, graphene aerogel microgranules (i.e., reducing the size of the bulk aerogels into microscale) and their performances in the electromagnetic field have been ignored. Herein, we report a new strategy to make floatable graphene aerogel microgranules with high hydrophobicity (137°), low density (13.5 mg/cm3), and high specific surface area (516 m2/g). These microgranules were synthesized initially from reduced graphene oxide (rGO) hydrogel microparticles and then in situ-modified by silica nanoparticles. Further investigations have demonstrated that the resulting silica-modified rGO aerogel microgranules possess highly efficient static electromagnetic screening (average 30.3 dB in 8-18 GHz) and dynamic infrared shielding (higher than 10 dB during floatation in air for 15 min) properties. The work reported here should give much inspiration to make more functional aerogel microgranules used in various emerging fields.

Interaction of Scutellaria-Coptis herb pair in improvement of glucose and lipid metabolism of type 2 diabetes rats based on response surface method / 药学学报

The response surface method was used to evaluate the concentration range, property and degree of Scutellaria (HQ) and Coptis (HL) herb pair on improvement of glucose and lipid metabolism in this paper. Type 2 diabetes mellitus (T2DM) was induced in rats by low a dose of streptozotocin (STZ) in combination with high-fat diet feeding. The rats were administered with HQ-HL extract pairs at different ratio (1:0, 3:1, 2:1, 3:2, 1:1, 2:3, 1:2, 1:3, 0:1). To investigate the influence of herb pair extracts on glucose and lipid metabolism of T2DM rats, the multi index synthetic index method was adopted to integrate the indexes, then the response surface method was applied to analyze the integration results. The ratio of HQ and HL from 3:1 to 1:3 showed a synergistic effect (with the value between -0.2 and -0.8). Especially, when the proportion was between 3:2 and 1:3, herb pair extracts possessed stronger synergistic effects (value:-0.8). The high dose of HQ-HL with the ratio of 1:1 exhibited the strongest synergistic effect.

Research on interaction between Coptidis Rhizoma extracts and intestinal bacteria / 中草药

Objective To investigate the interaction between Coptidis Rhizoma extracts and intestinal bacteria. Methods The metabolites of Coptidis Rhizoma extracts by human gut microbiota were identified by UPLC-Q-TOF/MS. Furthermore, the effects of Coptidis Rhizoma extracts on the growth of Bifiobactderia, Lactobacilli, Enterobacter, and Enterococcus were evaluated by the colorimetric method. Results Alkaloids in Coptidis Rhizoma were mainly degraded by reduction and demethoxy, among which berberine and coptisine were converted to reductive products and palmatine was metabolized to a demethoxyl product. Additionally, pathogens such as Enterobacter and Enterococcus were obviously inhibited and probiotics such as Lactobacilli and Bifiobactderia were notably promoted by Coptidis Rhizoma extracts. Conclusion Gut microflora can metabolize alkaloids from Coptidis Rhizoma by multiple ways, and Coptidis Rhizoma extracts can improve the intestinal microecology.

Clinical efficacy of bone transport technique in treatment of large segment infective nonunion of femoral shaft / 中华创伤杂志

Objective To investigate the clinical effect of bone transport technique in the treatment of large segment infective nonunion of femoral shaft.Methods A retrospective case series study was conducted to analyze the clinical data of 33 patients with large segment infective nonunion of femoral shaft admitted to Chinese PLA General Hospital from June 2012 to October 2015.There were 25 males and eight females,aged 19-58 years (mean,34.6 years).In terms of the initial injury,23 patients were with open fracture and 10 with closed fracture.All patients previously received 1-9 times of operation,with an average of 2.3 times.The duration from injury to operation ranged from 7-60 months,with an average of 34 months.All patients underwent treatment with bone transport technique.After thorough debridement,the length of femoral defect ranged from 6 cm to 18 ema,with an average of 10.5 cm.The single arm limb reconstruction external fixator was placed on the lateral side of the femur under C-ann X-ray fluoroscopy.The wound healing,bone healing time,external fixation index (EFI),and complications were recorded.The function of the affected limb was evaluated using the modified criteria of Association for the Study and Application of the Method of Ilizarov (ASAMI).Results All patients were followed up for 21-53 months (average,38.5 months).Femoral defects were completely repaired,with no recurrent infection reported.Bone healing time ranged from 8 months to 25 months (average,13 months).The external fixation index (EFI) ranged from 1.13 months/cm to 1.83 months/cm,with an average of 1.26 months/cm.The infection rate of the nail tract was 55％ (18/33).There were 12 patients with Type A,five with Type B,and one with Type C.The function of the affected limb was graded as excellent in 18 patients,good in six,fair in five,and poor in four,with an excellent and good rate of 73％ (24/33).Conclusions In the treatment of large segment infective nonunion of femoral shaft,bone transport technique can eontrol the infection,promote defect repair,and restore the function of affected limbs.

Possible Living Factors Influencing the Efficacy of Acupuncture Analgesia Between Chinese and Western Populations:Caffeine / 针刺研究

It has been known for thousands of years that acupuncture can relieve pain. However, the efficacy of acupuncture analgesia (AA) now has to be reconsidered due to negative reports from western countries. In the present study, the possible correlation between caffeine and the difference in AA in China and western countries was determined using the following factors:1) caffeine and pain; 2) adenosine, adenosine receptor and caffeine; 3) AA and caffeine. As a non-selective antagonist of the adenosine receptor, caffeine at low doses can be used as an adjuvant analgesic, and can augment antinociception combined with other analgesics. Caffeine can act as an important neural modulator, and adenosine can produce antinociception when combined with the A1 receptor located in spinal, supraspinal and peripheral tissue. A preclinical study demonstrated that caffeine at moderate doses could inhibit AA efficacy following plantar incision surgery in a mouse model. Caffeine is present in various foods, especially coffee, and approximately 85% of adults in western countries consume coffee regularly. Therefore, by reconsidering the correlation between caffeine, adenosine receptor and AA, and by determining the possible relationship between caffeine intake habits and AA efficacy, these findings will demonstrate the differences in AA between Chinese and western populations.

UPLC-Q-TOF/MS-based metabolic profiles of wogonoside by intestinal bacteria / 中草药

Objective To investigate the metabolic effects of wogonoside by human gut microbiota. Methods UPLC-Q-TOF/MS was used to analyze the metabolites of wogonoside. Additionally, 16 S rDNA molecular biology method was applied to the identification and composition analysis of intestinal bacteria. Results Wogonoside was mainly metabolized to wogonin and small quantities of demethylated metabolites. Most of Enterococcus and Escherchia had the metabolic abilities, among which a single bacterium Escherichia sp. 41 possessed the stronger metabolic activity. Conclusion This study has a good guiding significance for in vivo process and efficacy of wogonoside.

Ligation of intersphincteric fistula tract versus incision-thread-drawing procedure for complicated anal fistula: A Meta-analysis / 国际外科学杂志

Objective To systematically investigate the clinical efficiency and safety of ligation of inter sphincteric fistula tract versus incision-thread-drawing procedure for complicated anal fistula.Methods Searched PubMed,The Cochrane Library,CNKI,WanFang Data,and VIP from inception to May 2016,to collect randomized controlled trials of ligation of inter sphincteric fistula tract versus incision-thread-drawing procedure for complicated anal fistula.Search term included ligation of inter sphincteric fistula tract,fistula,incision-thread-drawing procedure,randomized controlled trial.The literatures were screened according to inclusive criteria,data were extracted and the quality of included studies was evaluated,and then meta-analysis was performed using RevMan 5.2 soft ware.A total of 5 randomized controlled trials including 305 patients were included.Results The results of meta-analysis showed that compared with incision-thread-drawing procedure,ligation of inter sphincteric fistula tract had a significant difference in amount of bleeding during surgery (MD =-18.30,95％ CI:-19.91 ～-16.69,P ＜ 0.000 01),the duration of pain (MD =-4.38,95％ CI:-4.69 ～-4.08,P ＜ 0.000 01),healing time (MD =-10.28,95％ CI:-15.71 ～-4.86,P =0.0002),hospital stay (MD =-7.44,95％CI:-10.87～-4.02,P＜0.000 1),recurrence rate (OR=0.31,95％CI:0.10～0.91,P=0.03).There was no significant difference in Operation time (MD =-5.83,95 ％ CI:-7.64 ～-4.02,P ＜ 0.000 01),effective percentage (OR =4.35,95％ CI:0.89 ～ 21.32,P =0.07) between both groups.Conclusion Compared with incision-thread-drawing procedure,ligation of inter sphincteric fistula tract shows significant advantage in cure rate,postoperative healing time,reducing post-operation pain,anal function protection and recurrence rate.

Optimization of Expression of Recombinant Human Tumor Necrosis Factor(hTNF-α) in Escherichia coliE.coli BL21 (DE3) / 现代检验医学杂志

Objective To construct a human tumor necrosis factor (hTNF-a) plasmid and identify it to optimize the fermentation conditions of hTNF-α protein so as to achieve high expression in Escherichia coli.Methods The gene of hTNF-a was cloned into pET24a vector to obtain the pET24a-hTNF-a expression plasmid that was transformed into Escherichia coli BL21(DE3),and the expression conditions of BL21 (DE3) were optimized.Results The plasmid of pET24a-hTNF-α was successfully constructed and identified by PCR and digestion,which was consistent with the target fragment hTNF-α.The plasmid was transformed into Escherichia coli BL21(DE3),the best induced expression conditions of Escherichia coli BL21 (DE3) were as follows:M9+LB medium,37℃,0.5 mmol/L IPTG,pH =7.5,and induction time was 5 h.The results showed that dry weight of the cells and the rate of TNF were increased by 2.56 times and 3.68 times,respectively,and the expression rate of hTNF-α was increased by 3.49 times from 9.38％ to 32.74％.Conclusion The optimal conditions for the expression of plasmid pET24a-hTNF-α in Escherichia coli were determined.

Degradation of silk fibroin/polylactic acid composites at different proportions in mice / 中国组织工程研究

BACKGROUND: In our previous study, we prepared some silk fibroin/polyactic acid composite materials at different proportions, which are verified as tissue-engineered materials with good performance by systemic hypersensitivity test, acute toxicity test, hemolysis test, pyrogenic test, and cell co-culture experiment. OBJECTIVE: To study the subcutaneous degradation of silk fibroin/polylactic acid composite materials at different proportions in mice. METHODS: Fifty-four ICR mice were subjected to subcutaneous cystic clearance on the both sides of the spine, and then randomized into three groups. The silk fibroin/polylactic acid composites at 40:60, 50:50, and 30:70 were implanted into the cystic space, respectively. The specimens were taken out at 1, 3, 9 weeks after implantation. Histopathological staining, Masson staining, and CD34 immunohistochemical staining were performed. RESULTS AND CONCLUSION: (1) Hematoxylin-eosin staining: At 9 weeks after implantation, new blood vessels gradually formed and visible fibroblasts gradually grew into the composites in the three groups. Structural collapse of the materials became more apparent, and tissues and cells further grew into the materials. The 40:60 and 50:50 composites were degraded more quickly than the other one. (3) Masson staining: At 9 weeks after implantation, mature blood vessels and collagen fibers were detectable in the three groups, which were more apparent in the 40:60 and 50:50 groups than the 30:70 group. The collagen fiber expression in the 50:50 group was significantly higher than that in the other two groups at different time after implantation (P < 0.05). (3) CD34 immunohistochemical staining: At 1-3 weeks after implantation, CD34 positive expression gradually increased in the three groups. After 9 weeks, the CD34 expression decreased in the three groups; however, the CD34 positive expression in the 50:50 group was significantly higher than that in the other two groups at different time after implantation (P < 0.05). To conclude, the silk fibroin/polylactic acid composite material at a proportion of 50:50 was degraded more quickly in mice.