In vivo fluorescence flow cytometry reveals that the nanoparticle tumor vaccine OVA@HA-PEI effectively clears circulating tumor cells

Tumor vaccine therapy offers significant advantages over conventional treatments,including reduced toxic side effects.However,it currently functions primarily as an adjuvant treatment modality in clinical oncology due to limitations in tumor antigen selection and delivery methods.Tumor vaccines often fail to elicit a sufficiently robust immune response against progressive tumors,thereby limiting their clinical efficacy.In this study,we developed a nanoparticle-based tumor vaccine,OVA@HA-PEI,utilizing ovalbumin(OVA)as the presenting antigen and hyaluronic acid(HA)and polyethyleneimine(PEI)as adjuvants and carriers.This formulation significantly enhanced the proliferation of immune cells and cytokines,such as CD3,CD8,interferon-,and tumor necrosis factor-,in vivo,effectively activating an immune response against B16–F10 tumors.In vivofluorescenceflow cytometry(IVFC)has already become an effective method for monitoring circulating tumor cells(CTCs)due to its direct,noninvasive,and long-term detection capabilities.Our study utilized a laboratory-constructed IVFC system to monitor the immune processes induced by the OVA@HA-PEI tumor vaccine and an anti-programmed death-1(PD-1)antibody.The results demonstrated that the combined treatment of OVA@HA-PEI and anti-PD-1 antibody significantly improved the survival time of mice compared to anti-PD-1 antibody treatment alone.Additionally,this combination therapy substantially reduced the number of CTCs in vivo,increased the clearance rate of CTCs by the immune system,and slowed tumor progression.Thesefindings greatly enhance the clinical application prospects of IVFC and tumor vaccines.

In Vivo Studies and Flow Cytometric Investigation on Anticancer Potential of Selenium Nanoparticles Synthesized via Aqueous Extract of Clerodendron phlomidis

Nowadays,doctors and nutritionists recommend individuals incorporate selenium-rich foods such as nuts,cereals,and mushrooms into their regular diet to maintain fitness and overall health.Selenium nanoparticles(SeNPs)exhibit strong chemopreventive capabilities.The anticipations for SeNPs with enhanced and tunable bioactive activities have led to a keen interest in phytofabrication.In this study,the aqueous extract of Clerodendron phlomidis plant leaves was utilized for the synthesis of SeNPs.In traditional Indian medicine,this plant extract is recognized as a significant anti-diabetic agent.The flavonoids tetrahydroxylflavone,7-hydroxyflavanone,and 6,4’-dimethyl-7-acetoxy-scutellarein present in this plant leaf extract demonstrate excellent anticancer activity.These secondary metabolites exhibit the ability to reduce sodium selenite into SeNPs.At a concentration of 13μg/mL,the synthesized SeNPs effectively inhibited the proliferation of the HepG2 cell line.The results suggest that the SeNPs possess promising anti-cancer potential against liver cancer and can be considered as a therapeutic agent for liver cancer treatment.Additionally,the cell cycle arrest induced by SeNPs was further confirmed by the fluorescence-activated cell sorting(FACS)method,indicating that SeNPs could efficiently differentiate cancer cells from normal cells.Notably,it showed a significant improvement in diethylnitrosamine(DEN)-induced Swiss Wistar rat groups.This scientific investigation highlights the high anti-cancer potential of SeNPs,positioning them as a promising therapeutic agent for liver cancer treatment.

Detection of cells by flow cytometry:Counting,imaging,and cell classification

The study of circulating cells in the blood stream is critical,as it covers many felds of biomed-icine,including immunology,cell biology,oncology,and reproductive medicine.In-viuo flowcytometry(IVFC)is a new tool to monitor and count cells in real time for long durations in theirnative biological environment.This review describes two main categories of IVFC,ie.,labeledand label-free IVFC.It focuses on label-free IVFC and introduces its technological developmentand related biological applications.Because cell recognition is the basis of flow cytometrycounting,this review also describes various methods for the classification of unlabeled cells,including the latest machine learning-based technologies.

Flow Regimes in Bubble Columns with and without Internals: A Review

Hydrodynamics characterization in terms offlow regime behavior is a crucial task to enhance the design of bubble column reactors and scaling up related methodologies.This review presents recent studies on the typicalflow regimes established in bubble columns.Some effort is also provided to introduce relevant definitions pertaining to thisfield,namely,that of“void fraction”and related(local,chordal,cross-sectional and volumetric)variants.Experimental studies involving different parameters that affect design and operating conditions are also discussed in detail.In the second part of the review,the attention is shifted to cases with internals of various types(perfo-rated plates,baffles,vibrating helical springs,mixers,and heat exchanger tubes)immersed in the bubble columns.It is shown that the presence of these elements has a limited influence on the global column hydrodynamics.However,they can make the homogeneousflow regime more stable in terms of transition gas velocity and transi-tion holdup value.The last section is used to highlight gaps which have not beenfilled yet and future directions of investigation.

Reversible solid-liquid conversion enabled by self-capture effect for stable non-flow zinc-bromine batteries

Non-flow aqueous zinc-bromine batteries without auxiliary components(e.g.,pumps,pipes,storage tanks)and ion-selective membranes represent a cost-effective and promising technology for large-scale energy storage.Unfortunately,they generally suffer from serious diffusion and shuttle of polybromide(Br^(-),Br^(3-))due to the weak physical adsorption between soluble polybromide and host carbon materials,which results in low energy efficiency and poor cycling stability.Here,we develop a novel self-capture organic bromine material(1,10-bis[3-(trimethylammonio)propyl]-4,4'-bipyridinium bromine,NVBr4)to successfully realize reversible solid complexation of bromide components for stable non-flow zinc-bromine battery applications.The quaternary ammonium groups(NV^(4+)ions)can effectively capture the soluble polybromide species based on strong chemical interaction and realize reversible solid complexation confined within the porous electrodes,which transforms the conventional“liquid-liquid”conversion of soluble bromide components into“liquid-solid”model and effectively suppresses the shuttle effect.Thereby,the developed non-flow zinc-bromide battery provides an outstanding voltage platform at 1.7 V with a notable specific capacity of 325 mAh g^(-1)NVBr4(1 A g^(-1)),excellent rate capability(200 mAh g^(-1)NVBr4 at 20 A g^(-1)),outstanding energy density of 469.6 Wh kg^(-1)and super-stable cycle life(20,000 cycles with 100%Coulombic efficiency),which outperforms most of reported zinc-halogen batteries.Further mechanism analysis and DFT calculations demonstrate that the chemical interaction of quaternary ammonium groups and bromide species is the main reason for suppressing the shuttle effect.The developed strategy can be extended to other halogen batteries to obtain stable charge storage.

基于VRB/OW-GFRP混合结构的CTB电池包上盖总成轻量化设计研究

电池车身一体化(CTB)是提升电动汽车续航里程的关键技术。利用胶接工艺将变厚度(VRB)结构与正交编织玻璃纤维增强复合材料(OW-GFRP)粘接形成的VRB/OW-GFRP混合结构,是降低CTB电池包质量的创新结构,有助于进一步提升电动汽车的续航里程。以某款电动汽车为研究对象,设计了一种CTB电池车身一体化结构,实现了电池包上盖与车身地板的集成融合。分别采用VRB结构、UT/OW-GFRP及VRB/OW-GFRP混合结构替代等厚度(UT)CTB电池包上盖总成,并基于多阶段优化方法开展了3种类型CTB电池包上盖总成的轻量化设计。结果表明,在满足CTB电池包刚度性能前提下,VRB结构相比UT结构实现减质量6.4%;基于VRB/OW-GFRP混合结构的CTB电池包上盖总成轻量化效果约为金属结构的3倍,VRB/OW-GFRP相比UT/OW-GFRP混合电池包上盖总成进一步减质量4.2%。由此可见,VRB/OW-GFRP混合结构是未来汽车轻量化技术发展的重要趋势,在CTB电池包上盖总成中具有巨大的应用前景。

A dual-RPA based lateral flow strip for sensitive,on-site detection of CP4-EPSPS and Cry1Ab/Ac genes in genetically modified crops

Traditional transgenic detection methods require high test conditions and struggle to be both sensitive and efficient.In this study,a one-tube dual recombinase polymerase amplification(RPA)reaction system for CP4-EPSPS and Cry1Ab/Ac was proposed and combined with a lateral flow immunochromatographic assay,named“Dual-RPA-LFD”,to visualize the dual detection of genetically modified(GM)crops.In which,the herbicide tolerance gene CP4-EPSPS and the insect resistance gene Cry1Ab/Ac were selected as targets taking into account the current status of the most widespread application of insect resistance and herbicide tolerance traits and their stacked traits.Gradient diluted plasmids,transgenic standards,and actual samples were used as templates to conduct sensitivity,specificity,and practicality assays,respectively.The constructed method achieved the visual detection of plasmid at levels as low as 100 copies,demonstrating its high sensitivity.In addition,good applicability to transgenic samples was observed,with no cross-interference between two test lines and no influence from other genes.In conclusion,this strategy achieved the expected purpose of simultaneous detection of the two popular targets in GM crops within 20 min at 37°C in a rapid,equipmentfree field manner,providing a new alternative for rapid screening for transgenic assays in the field.

A multichannel thermal bubble-actuated impedance flow cytometer with on-chip TIA based on CMOS-MEMS

Electrochemical impedance spectroscopy(EIS)flow cytometry offers the advantages of speed,affordability,and portability in cell analysis and cytometry applications.However,the integration challenges of microfluidic and EIS read-out circuits hinder the downsizing of cytometry devices.To address this,we developed a thermal-bubble-driven impedance flow cytometric application-specific integrated circuit(ASIC).The thermal-bubble micropump avoids external piping and equipment,enabling high-throughput designs.With a total of 36 cell counting channels,each measuring 884×220μm^(2),the chip significantly enhances the throughput of flow cytometers.Each cell counting channel incorporates a differential trans-impedance amplifier(TIA)to amplify weak biosensing signals.By eliminating the parasitic parameters created at the complementary metal-oxidesemiconductor transistor(CMOS)-micro-electromechanical systems(MEMS)interface,the counting accuracy can be increased.The on-chip TIA can adjust feedback resistance from 5 to 60 kΩto accommodate solutions with different impedances.The chip effectively classifies particles of varying sizes,demonstrated by the average peak voltages of 0.0529 and 0.4510 mV for 7 and 14μm polystyrene beads,respectively.Moreover,the counting accuracies of the chip for polystyrene beads and MSTO-211H cells are both greater than 97.6%.The chip exhibits potential for impedance flow cytometer at low cost,high-throughput,and miniaturization for the application of point-of-care diagnostics.

Performance Evaluation of Combined Detection of Serum CEA,CYFRA21-1,CA125,and NSE in Patients with Lung Cancer by Fluorescence Flow Cytometry

Objective:To investigate the effect of combined detection of serum carcinoembryonic antigen(CEA),cytokeratin 19 fragment(CYFRA21-1),cancer antigen 125(CA125),and neuron-specific enolase(NSE)in patients with lung cancer by fluorescence flow cytometry.Methods:From August 2019 to July 2022,200 patients with lung cancer diagnosed by pathology in our hospital were retrospectively analyzed.2 mL venous blood was collected in a fasting state and centrifuged to separate the serum(containing human chorionic gonadotropin antibody[anti-hCG antibody],hepatitis B surface antibody[anti-HBs antibody],and CEA).Results:The sensitivities of CEA and CYFRA21-1 detected via enzyme-linked immunosorbent assay(ELISA)were 100%,and the detection limits were 0.5 ng/mL and 0.1 ng/mL,respectively;the sensitivities of CA125 and NSE detected via flow cytometry were 100%,and the detection limits were 10 U/mL and 2 ng/mL,respectively.Compared with ELISA,the sensitivities of CA125 and NSE detected via flow cytometry were higher.When the concentration of CEA was 10-40 ng/mL,the sensitivities of the three markers CYFRA21-1,CA125,and NSE showed no significant changes(P>0.05);when the concentration of CEA was 40-80 ng/mL,the sensitivity of CEA significantly decreased(P<0.01),but the sensitivities of the three markers CYFRA21-1,CA125,and NSE showed no significant changes(P>0.05);when the concentration of CEA was 80-200 ng/mL,the sensitivities of all four markers showed no significant changes(P>0.05).Conclusion:Compared with the double-antibody sandwich ELISA,fluorescence flow cytometry has certain advantages,including high sensitivity,good precision,short detection time,low sample usage,and low medical cost;thus,it is worthy of clinical promotion.

Double-Doped Carbon-Based Electrodes with Nitrogen and Oxygen to Boost the Areal Capacity of Zinc-Bromine Flow Batteries

Ensuring a stable power output from renewable energy sources,such as wind and solar energy,depends on the development of large-scale and long-duration energy storage devices.Zinc–bromine fl ow batteries(ZBFBs)have emerged as cost-eff ective and high-energy-density solutions,replacing expensive all-vanadium fl ow batteries.However,uneven Zn deposition during charging results in the formation of problematic Zn dendrites,leading to mass transport polarization and self-discharge.Stable Zn plating and stripping are essential for the successful operation of high-areal-capacity ZBFBs.In this study,we successfully synthesized nitrogen and oxygen co-doped functional carbon felt(NOCF4)electrode through the oxidative polymerization of dopamine,followed by calcination under ambient conditions.The NOCF4 electrode eff ectively facilitates effi cient“shuttle deposition”of Zn during charging,signifi cantly enhancing the areal capacity of the electrode.Remarkably,ZBFBs utilizing NOCF4 as the anode material exhibited stable cycling performance for 40 cycles(approximately 240 h)at an areal capacity of 60 mA h/cm^(2).Even at a high areal capacity of 130 mA h/cm^(2),an impressive energy effi ciency of 76.98%was achieved.These fi ndings provide a promising pathway for the development of high-areal-capacity ZBFBs for advanced energy storage systems.

Analysis of Snow Distribution and Displacement in the Bogie Region of a High-Speed Train

Snow interacting with a high-speed train can cause the formation of ice in the train bogie region and affect its safety.In this study,a wind-snow multiphase numerical approach is introduced for high-speed train bogies on the basis of the Euler-Lagrange discrete phase model.A particle-wall impact criterion is implemented to account for the presence of snow particles on the surface.Subsequently,numerical simulations are conducted,considering various snow particle diameter distributions and densities.The research results indicate that when the particle diameter is relatively small,the distribution of snow particles in the bogie cavity is relatively uniform.However,as the particle diameter increases,the snow particles in the bogie cavity are mainly located in the rear wheel pairs of the bogie.When the more realistic Rosin-Rammler diameter distribution is applied to snow particles,the positions of snow particles with different diameters vary in the bogie cavity.More precisely,smaller diameter particles are primarily located in the front and upper parts of the bogie cavity,while larger diameter snow particles accumulate at the rear and in the lower parts of the bogie cavity.

Pairing nitroxyl radical and phenazine with electron-withdrawing/-donating substituents in “water-in-ionic liquid” for high-voltage aqueous redox flow batteries

Aqueous redox-active organic materials-base electrolytes are sustainable alternatives to vanadium-based electrolyte for redoxflow batteries(RFBs)due to the advantages of high ionic conductivity,environmentally benign,safety and low cost.However,the underexplored redox properties of organic materials and the narrow thermodynamic electrolysis window of water(1.23 V)hinder their wide applications.Therefore,seeking suitable organic redox couples and aqueous electrolytes with a high output voltage is highly suggested for advancing the aqueous organic RFBs.In this work,the functionalized phenazine and nitroxyl radical with electron-donating and electron-withdrawing group exhibit redox potential of-0.88 V and 0.78 V vs.Ag,respectively,in“water-in-ionic liquid”supporting electrolytes.Raman spectra reveal that the activity of water is largely suppressed in“water-in-ionic liquid”due to the enhanced hydrogen bond interactions between ionic liquid and water,enabling an electrochemical stability window above 3 V.“Water-in-ionic liquid”supporting electrolytes help to shift redox potential of nitroxyl radical and enable the redox activity of functionalized phenazine.The assembled aqueous RFB allows a theoretical cell voltage of 1.66 V and shows a practical discharge voltage of 1.5 V in the“water-in-ionic liquid”electrolytes.Meanwhile,capacity retention of 99.91%per cycle is achieved over 500 charge/discharge cycles.A power density of 112 mW cm^(-2) is obtained at a current density of 30 mA cm^(-2).This work highlights the importance of rationally combining supporting electrolytes and organic molecules to achieve high-voltage aqueous RFBs.

Numerical Simulation and Optimization of the Gas-Solid Coupled Flow Field and Discharging Performance of Straw Crushers

The quality of crushing,power consumption,and discharging performance of a straw crusher are greatly influenced by the characteristics of its internalflowfield.To enhance the straw crusher’sflowfield properties and improve the efficiency with which crushed material is discharged,first,the main structural parameters influencing the airflow in the crusher are discussed.Then,the coupled gas-solidflowfield in the straw crusher is numerically calculated through solution of the Navier-Stokes equations and application of the discrete element method(DEM).Finally,the discharge performance index of the crusher is examined through detailed analysis of the crushed material dynamics.Additionally,a multi-island genetic algorithm is used to optimize the structure and operational factors that have significant effects on the discharge performance.With optimization,the accumulation rate of crushed materials in the bottom region of the straw crusher decreases by 20.08%,and the massflow rate at the discharge outlet increases by 11.63%.

Impact of the Inlet Flow Angle and Outlet Placement on the Indoor Air Quality

This study aims to optimize the influence of the inlet inclination angle on the Indoor Air Quality(IAQ),heat,and temperature distribution in mixed convection within a two-dimensional square cavityfilled with an air-CO_(2)mixture.The air-CO_(2)mixture enters the cavity through two inlet openings positioned at the top wall,which is set at the ambient temperature(TC).Three values of the Reynolds numbers,ranging from 1000 to 2000,are considered,while the Prandtl number is kept constant(Pr=0.71).The temperature distribution and streamlines are shown for Rayleigh number(Ra)equal to 104,three inlet inclination anglesϕ(0,π/6 andπ/4)and three CO_(2)concentrations values(1500,2500,3500 ppm)applied at both hot vertical walls(maintained at a constant temperature TH).Afinite volume method is used under the assumption of two-dimensional laminarflow to solve the NavierStokes and energy equations.The results indicate that inlet inclination angle has an impact on the indoor air quality(IAQ),which,in turn,affects the heat transfer distribution and thermal comfort within the cavity.

Simulation of Two-Phase Flowback Phenomena in Shale Gas Wells

The gas-water two-phaseflow occurring as a result of fracturingfluidflowback phenomena is known to impact significantly the productivity of shale gas well.In this work,this two-phaseflow has been simulated in the framework of a hybrid approach partially relying on the embedded discrete fracture model(EDFM).This model assumes the region outside the stimulated reservoir volume(SRV)as a single-medium while the SRV region itself is described using a double-medium strategy which can account for thefluid exchange between the matrix and the micro-fractures.The shale gas adsorption,desorption,diffusion,gas slippage effect,fracture stress sensitivity,and capillary imbibition have been considered.The shale gas production,pore pressure distribution and water saturation distribution in the reservoir have been simulated.The influences of hydraulic fracture geometry and nonorthogonal hydraulic fractures on gas production have been determined and discussed accordingly.The simulation results show that the daily gas production has an upward and downward trend due to the presence of a large amount of fracturingfluid in the reservoir around the hydraulic fracture.The smaller the angle between the hydraulic fracture and the wellbore,the faster the daily production of shale gas wells decreases,and the lower the cumulative production.Nonplanar fractures can increase the control volume of hydraulic fractures and improve the production of shale gas wells.

The Clinical Value of Detecting the Level of Exfoliated Cells in Pleural Effusion by Flow Cytometry in the Differential Diagnosis of Non-

Objective:To explore the value of flow cytometry(FCM)in detecting the level of exfoliated cells in pleural effusion in the differential diagnosis of non-small cell lung cancer and benign lung diseases.Methods:Clinical data of patients with non-small cell lung cancer who were hospitalized in Hebei hospital from June 2019 to March 2022 were collected.A total of 98 patients were included,and 63 patients with alveolar lung disease were screened during the same period,and the two groups of patients were analyzed.Results:Compared with alveolar lung disease group,FCM detection and analysis showed that the level of exfoliated cells in the pleural effusion of non-small cell lung cancer(NSCLC)patients was 99(3-969)/100,000,and patients with alveolar lung disease was 4(0~19)/100,000.Additionally,compared with the alveolar lung disease group,the level of exfoliated cells in the pleural effusion of patients with non-small cell lung cancer(NSCLC)was significantly increased(P<0.001).The diagnostic efficacy of FCM for detecting pleural fluid exfoliated cells in non-small cell lung cancer was assessed using ROC curves and using 95%CI(-11.1,-13.2)with a sensitivity of 0.75 and specificity of 0.94,and the diagnostic efficacy of FCM for detecting pleural fluid exfoliated cells in alveolar lung disease was assessed using 95%CI(-11.1,-13.2)with a sensitivity of 0.71 and specificity of 0.87.Conclusion:Flow cytometry has a wider range of clinical applications,simple operation,low cost,and high sensitivity,which makes it of great significance in disease diagnosis.

直播信息特性和产品感知对冲动购买的影响研究——基于Howard-Sheth模型

基于Howard-Sheth模型,本文从外部信息和感知刺激角度实证探索社交电商直播信息特征和产品感知价值对冲动购买意愿的影响机制,采取便利性抽样收集245份有效问卷,运用AMOS-结构方程模型对效应路径进行实证检验。结果表明:社交电商直播信息交互性、产品感知享乐价值和感知实用价值对心流体验有显著的促进作用,心流体验进一步影响消费者冲动购买意愿;信息时效性对心流体验的影响不显著。基于此,文章通过将Howard-Sheth模型拓展到社交电商直播场景中,并为社交电商提出几点营销思考进而为电子商务行业理解社交电商消费者行为提供了新视角。

Flow Cytometric Evidence for Hydroxyl Radical-induced Apoptosis in Tobacco Protoplasts

Protoplasts prepared from tobacco (Nicotiana tabacum L., cultivar BY-2) suspension cells have similar morphological characteristics to those in animal cells. The hallmarks of apoptosis such as condensation and peripheral distribution of nuclei, TUNEL positive reaction, and DNA ladders were observed when tobacco protoplasts were treated with the hydroxyl radical generating system (1.0 mmol/L FeSO4/0.5 mmol/L H2O2). In animals, the loss of transmembrane potential (DeltaPsi(m)) and the exposure of phospholipid phosphatidylserine (PS) are believed to be the main apoptosis events. To test whether these significant processes take place in plants, flow cytometry was used to detect annexin V binding and changes in DeltaPsi(m). Results showed that the PS turned out from inner membrane and DeltaPsi(m) gradually decreased during the apoptosis. All these apoptotic characteristics proved that hydroxyl radicals can cause typical programmed cell death (PCD) in tobacco protoplasts and this design can be served as an effective experiment system to explore the mechanism of plant apoptosis.

A Novel Three-parameter Flow Cytometric Analysis for Cell Cycle

To set up a three-parameter method for cell cycle analysis by two-laser flowcy-tometer, which can detect two types of cyclin plus DNA content in one measurement, and thatanalyze unscheduled expression of cyclins. Methods: Three-color fluorescence was used for analysisof two types of cyclins and DNA content simultaneously in individual cells by two-laser flowcytometry. MOLT-4 cells were used to study the expression of major cyclins in mammalian cells. ATriton-X100 permeabilization procedure was optimized for detection of two types of cyclins. Onecyclin was stained directly with a FITC-conjugated monoclonal antibody (mAb), and the other,indirectly with RPE-Cy5-conjugated secondary antibody, while DNA was stained with the fluorochromeDAPI. mAMSA and mimosine treated MOLT-4 cells were used to test this three-parameter method.Results: Permeabilization with 0.5% Triton-XlOO in PBS containing 1% BSA for 5 min on ice providedoptimal conditions for the simultaneous labelling of two cyclins plus DNA in single cells. It wasfound that the emission spectrum of the three dyes (DAPI, FITC and RPE-Cy5) could be measured withno compensation. Based on cyclinA/cyclinE/DNA flow cytometric analysis, asynchronously growingMOLT-4 cells could be divided into 6 compartments (G1o, G1e, G1l, S, G2, and M) simultaneously,allowing for analysis of cell cycle phase specific perturbations without the necessity of cellsynchronization. Unscheduled cyclin B1 expression was observed in G1 cells treated with mimosine andcyclin E in G2 cells treated with mAMSA. We found that unscheduled cyclin expression paralleledexpected cyclin expression. Conclusion: Thus, three-color FCM analysis of cells may not only beapplied to measure unscheduled vs. expected cyclin expression but may also be used to estimate thefraction of cycling cells in up to 6 cell populations.

Radio-protective effect of vitamin E on spermatogenesis in mice exposed to γ-irradiation: a flow cytometric study

Aim: To investigate the effect of vitamin E on the radioprotection of spermatogenesis and chromatin condensation of spermatozoa during passage through the epididymis in mice exposed to irradiation. Methods: Adult outbred male ICR mice were orally administered natural vitamin E (VE, D-α-tocopheryl acetate) at 400 IU/kg for 7 days before exposure to 1 Gy of γ-irradiation. The animals were sacrificed at day 1, 7, 14, 21, 28, 35 and 70 post-irradiation (IR) and the percentage of testicular germ cells and epididymal sperm chromatin condensation was analyzed using flow cytometry. Results: Serum D-α-tocopheryl acetate levels were 47.4 ± 3.2 μg/dL in the treated group, yet it could not be detected in the control group. The testicular weight of irradiated mice pretreated with VE+IR was significantly (P<0.05) higher than that of those without VE treatment (IR) at day 14 and 21 post-irradiation. The percentage of primary spermatocytes (4C) in the VE+IR group was comparable to the controls but significantly (P<0.05) higher than those in the IR group from day 7 to 35 post-irradiation. The percentage of round spermatids (1C) in the VE+IR group was also significantly (P<0.05) higher than those in the IR group at day 28 post-irradiation. The primary spermatocytes : spermatogonia ratio in the IR group was significantly (P<0.05) declined at day 7 to 35 post-irradiation when compared to the VE+IR and control groups. The round spermatid : spermatogonia ratio in the VE+IR group was significantly (P<0.05) higher than that of the IR group at day 14 and 28 post-irradiation. The chromatin condensation of epididymal spermatozoa measured by propidium iodide uptake was not affected by 1 Gy of γ-irradiation. Conclusion: The administration of VE prior to irradiation protects spermatogenic cells from radiation.