Effect of kinetin on immunity and splenic lymphocyte proliferation in vitro in D-galactose-induced aging rats / 生理学报

The purpose of this paper is to study the effect of kinetin (Kn) on immunity and splenic lymphocyte proliferation in vitro of aging rats induced by D-galactose (D-gal). Fifty SD rats were randomly divided into five groups: control group, aging model group, Kn low dose group, Kn middle dose group and Kn high dose group. The aging model group was proposed by napes subcutaneous injection of D-gal (125 mg/kg) for 45 d, and anti-aging groups were intragastrically administered with 5, 10, 20 mg/kg of Kn respectively from day 11. IgG, IgA, IgM contents of serum, the apoptosis percentage, stimulation index (SI) and proliferation index (PI) of splenic lymphocyte in vitro were evaluated. The results showed that the apoptosis percentage of splenic lymphocyte in aging model rats was higher, the serum IgG, IgA and IgM contents, SI and PI were lower than control group. Kn significantly decreased the apoptosis percentage of splenic lymphocyte, while increased the serum IgG, IgA and IgM contents, SI and PI in aging model group. These results suggest that Kn could inhibit the apoptosis, while promote the proliferation of splenic lymphocyte, and then effectively enhance the immune power of the aging rats and slow down the aging process.

Effect of kinetin on ovary and uterus in D-galactose-induced female mouse model of aging / 生理学报

The present study was to investigate the effect of kinetin on ovary and uterus of D-galactose-induced female mouse model of aging. Aging female mice model caused by D-galactose were used as model group, the aging model mice intragastrically administered with kinetin solution (daily 25 mg/kg or 50 mg/kg) were used as kinetin groups, and the mice with solvent as normal group (n = 20). To detect the effects of kinetin, estrous cycle, estradiol content, ovarian and uterine wet weight and organ index, SOD and GSH-Px activities, MDA and total protein contents, as well as the reserve function of ovaries were examined. The results showed that, kinetin-induced changes in two kinetin groups were observed, compared with the model group: (1) the estrous cycle was shortened; (2) serum estradiol content was significantly increased; (3) the wet weights of the ovary and uterus were increased significantly; (4) SOD and GSH-Px activities of ovary and uterus were significantly higher; (5) the MDA contents of the ovary and uterus were reduced significantly; (6) total protein contents of the ovary and uterus were increased significantly; (7) the numbers of mature oocytes in fallopian tubes were increased significantly. The results show that kinetin can protect ovary and uterus against oxidative damage, prevent low estrogen secretion caused by ovarian oxidative damage, shorten the estrous cycle in mice, and eventually maintain ovarian and uterine vitalities.

Application of atomic force microscopy in ultrastructure and biomechanics of cells and biomacromolecules / 医用生物力学

To be the representative fruition resulted from the rapid development in micro-nano theory and technology, atomic force microscopy (AFM) has greatly promoted the expansion of biological research in micro-nano scale, and facilitated the birth and development of micro-nano biology as an important technique in its 25-year evolutional progress. Based on the fundamental principles and detection modes of AFM, as well as the author’s research findings and work experience in this field, the paper reviews the application of AFM in the study on ultrastructure and biomechanical properties of cells and biomacromolecules in the aspects of biological structure and morphology, surface physicochemical characterization and mechanical manipulation of biological macromolecules, and focus on some important scientific and technical problems on AFM in micro-nano biomedical research needed to be improved and solved urgently, with exploratory insights and recommendations for potential users in ultrastructure and biomechanics of cells and biomacromolecules.

Effect of vinblastine nanoparticles on antiproliferation in human glioma cell lines BT325 / 中国中药杂志

<p><b>OBJECTIVE</b>To compare antiproliferation effects of vinblastine nanopraticles and vinblastine water solution in human glioma cell lines BT325.</p><p><b>METHOD</b>Vinblastine nanoparticles were prepared by emulsion polymerization process and using dextran as a stabilizing agent. It was characterized by means of morphology, size, drug entrapment efficiency and loading efficiency. Human glioma cell lines BT325 were treated with different concentrations of vinblastine nanoparticles and vinblastine water solution for 48 h, Antiproliferation effect was measured by MTT method. Morphological changes were observed by inverted microscope, transmission electron microscope and scanning electron microscope.</p><p><b>RESULT</b>Mean diameter of VLB-PBCA-NP was about 74.4 nm, and drug entrapment efficiency and loading efficiency was 78.47% and 39.24%, respectively. Cell growth inhibition rate of vinblastine nanoparticles group and vinblastine water solution group in a concentration range (5-5 000 g x L(-1)) for 48 h was 41%, 49%, 73%, 83% and 28%, 33%, 54%, 60% respectively. Entrapment of VLB in NPS may distinctly degrade absorbency as compared to free drugs. Glioma cell BT325 which treated with VLB water solution were initial stage of apoptosis, and apoptosis body were forming. But VLB NPS-treated BT325 cells were intermediate or end stage, and missed structure integrality.</p><p><b>CONCLUSION</b>VLB-PBCA-NP and VLB water solution could inhibit the growth of human glioma cell lines BT325, and VLB nanoparticles have stronger inhibition effect compared with VLB water solution in the same dose. PBCA may be effective as promising carrier for the transport of vinblastine into the glioma cells.</p>

Study on Gambogic Acid-loaded Polylacticacid Nanoparticles / 中国生物工程杂志

Gambogic acid-loaded polylacticacid nanoparticles (GA-PLA-NPs) were prepared by modified emulsification solvent diffusion. The shape of nanoparticles was observed by transmission electron microscope (TEM).The size distribution and mean diameter were measured by laser particle size analyzer. The entrapment efficiency and content of drug loading were determined by Ultraviolet Spectrophotometer after ultracentrifugation. GA-PLA-NPs release behavior in vitro was carried out. The acute toxicity were carried out to study the security of GA-PLA-NPs. The preparation process adapted to the formulation was as follows: the volume ratio of the aqueous and organic was 2∶1(v/v), the surfactant concentration in aqueous was 0.5%,the drug concentration in organic was 0.1%(w/v), GA∶PLA was 1∶4(w/w). The mean diameter was 51.36nm for the nanoparticles prepared by above conditions.The entrapment efficiency and content of drug loading were 98.87 % and 13.3 %. The release behavior of drug in vitro showed an initial burst effect with subsequently a slower rate stage. The LD50 value of GA-PLA-NPs on mouse was 26.3 mg/kg. The results showed that the GA-PLA-NPs were well prepared with stable quality and high dispersion. PLA-NPs might be used as a new carrier for gambogic acid.

Experimental study of cardiac muscle tissue engineering in bioreactor / 中国医学科学院学报

<p><b>OBJECTIVE</b>This study investigates construction of cardiac muscle cell-porous collagen scaffold complex in a bioreactor so as to unveil the possibility of generating 3-dimensional cardiac muscle tissue under the environment that mimics microgravity in vitro.</p><p><b>METHODS</b>1-2-day old neonatal rat cardiac muscle cells were isolated by sequential digestion and pre-plating methods, then seeded onto porous collagen scaffold. The cell-collagen complex was transferred into rotary cell culture system (RCCS) and incubated for 7 days. Cells cultured in 75 ml flasks and constructs cultures on plates served as control. Morphological changes of the cells were observed by light microscope and metabolic rate was recorded. Ultrastructure of the cells growing in porous collagen was observed by transmission electron microscopy. Content of total DNA and protein in the newly-formed tissue were analyzed. H-E and anti-sarcomeric alpha-actin stains were performed in comparison with native cardiac muscle.</p><p><b>RESULTS</b>The isolated cardiac muscle cells adhered to the bottom of the flasks 24 hours after plating and began to beat spontaneously. When incubated for 7 days in RCCS, cell-collagen constructs of form a continuous outer tissue layer containing cells aligned with each other. The cell population in the interior of the construct was less in density than the outer part. Transmission electron microscopy demonstrated that subcellular elements characteristic of cardiac myocytes were in the outermost layer of constructs. A strongly positive stains of anti-sarcomeric alpha-actin suggested presence of cell population of differentiated cardiac myocytes in these constructs. Construct biomass was not significantly different from that in neonatal rat ventricle and approximately 40% of that in adult rat ventricles. Construsts in plates contained a few of cells which were less than those in RCCS. Metabolic activity of cells cultured in RCCS was higher than that in flasks and plates.</p><p><b>CONCLUSIONS</b>Dissociated cardiac muscle cells cultured on 3-dimensional scaffolds in RCCS under favorable conditions can form engineered constructs with structural and functional features resembling those of native cardiac tissue.</p>