[Antagonistic effect of quercetin on PM2.5 toxicity in the rat's embryonic development in vitro].

OBJECTIVE: To explore the antagonistic effect of quercetin on fine particulate matter (PM2.5)-induced embryonic developmental toxicity in vitro. METHODS: PM2.5 was collected on glass fiber filters by PM2.5 samplers during the heating period of Dec. 2015 to Mar. 2016 in an area of Haidian District, Beijing City. The sampled filters were cut into 1 cm×3 cm pieces followed by sonication. The PM2.5 suspension was filtered into a 10 cm glass dish through 8 layers of sterile carbasus and stored at -80 °C until freeze drying. Frozen PM2.5 suspension was dried by vacuum freeze-drying. In vitro post-implantation whole embryo culture was used in this study. Pregnant rats with 9.5 gestation days (GD) were killed by cervical dislocation and the uteri were removed into sterile Hank's solution. The embryos with intact yolk sacs and ecto placental cones were induced by PM2.5, and then subjected to intervention of quercetin at the doses of 0.1 µmol/L, 0.5 µmol/L, 1.0 µmol/L and 5.0 µmol/L, respectively. At the end of the 48 h culture period, the cultures were terminated, and all embryos were removed from the culture bottles and placed in prewarmed Hank's solution for evaluation. Morphological evaluation of the embryos was conducted under a stereomicroscope using the morphologic scoring system by Brown and Fabro. The mitochondrial reactive oxygen species (ROS) level was detected by FACSCalibur flow cyto-metry using MitoSOXTM Red staining. RESULTS: An obvious antagonistic effect was achieved through quercetin at the dose of 1.0 µmol/L, which could result in an increase of visceral yolk sac (VYS) diameter, crown-rump length and head length, somite number, and the differentiation of visceral yolk sac vascular vessels. The scores of allantois, flexion, heart, hind brain, midbrain, forebrain, auditory system, visual system, olfactory system, branchialarch, maxillary process, forelimb bud and hindlimb bud also revealed a significant increase and the relative mitochondrial ROS level of embryonic cells was significantly decreased when compared with PM2.5 group. Although quercetin at the doses of 0.1 µmol/L, 0.5 µmol/L, 5.0 µmol/L also exhibited protective effects against PM2.5-induced embryonic developmental toxicity, the protective effect was weaker when compared with the dose of 1.0 µmol/L. CONCLUSION: Quercetin at proper dose may be of great benefit for the development of embryos exposed to PM2.5 in the uterus of the rats. Quercetin provides an effective strategy for the prevention of PM2.5-induced embryonic developmental toxicity. Clearance of mitochondrial ROS may be one of its mechanisms.

[The composition of gut microbiota in infant and its influencing factors].

Gut microbiota provide enzymes and additional biochemical metabolic pathways for the host, which together with the host genome and the external environment, influence the body function. The composition of gut microbiota in infant is closely related to health in later life. However, it is influenced by many factors, including delivery mode, feeding pattern, prenatal diet, pregnancy psychology and antepartum antibiotic treatment. Vaginal delivery and breastfeeding is beneficial for shaping gut microbiota, while cesarean section and formula feeding would reduce the amount of gut dominant bacteria. In addition, inappropriate diet during pregnancy, prenatal stress and antepartum antibiotic treatment alters bacterial colonization of the gut in infant.

[Immunomodulatory effect of oyster peptide on immunosuppressed mice].

OBJECTIVE: To evaluate the immunomodulating effect of oyster peptide on immunosuppressed mice. METHODS: ICR mice injected with cyclophosphamide (CTX) were adopted as the module group, with mice without treatment as the control group, and different dosages of oyster peptide (0.5 g/kg, 1.0 g/kg, and 2.0 g/kg) were given to the low, middle, and high groups for 15 days. The body weight, spleen, and thymus weight of the mice, structures under the microscope of the immune organs, numbers of white blood cells, ratios of T lymphocyte subsets, immune cytokines and numbers of nuclear cells, and DNA content in bone marrow were all assessed. RESULTS: Compared with the control group, the structures of thymus and spleen of the mice in the CTX group appeared obscure and shrunk when observed under microscope, the number of their white blood cells declined (P=0.04), the proportion of their CD3(+) T cells in peripheral blood declined (P=0.003), the proportion of their CD8(+) T cells in peripheral blood declined (P=0.002), the concentration of their IL-5 in peripheral blood significantly increased (P<0.01), the concentration of their nucleated cells and DNA density in bone marrow decreased (P=0.04, P<0.01). Oyster could improve the structures of thymus and spleen of the immunosuppressed mice. Compared with the CTX group, the number of white blood cells in 2.0 g/kg group increased (P=0.003), the proportion of CD3(+) T cells in peripheral blood in 1.0 g/kg group (P=0.04) and 2.0 g/kg group (P=0.02) increased, the proportion of CD8(+) T cells in peripheral blood in 2.0 g/kg group increased (P=0.002), the concentration of IL-5 in peripheral blood in all the oyster treated groups increased (P<0.01 in 0.5 g/kg, 1.0 g/kg, and 2.0 g/kg groups), the concentration of IL-17 in peripheral blood in 2.0 g/kg group decreased (P=0.03), the concentration of nucleated cells in bone marrow of all the oyster treated groups increased (0.5 g/kg vs. CTX, P=0.04; 1.0 g/kg vs. CTX, P=0.02; 2.0 g/kg vs. CTX P=0.01), the DNA content in bone marrow of all the oyster treated groups increased (P<0.01 in the 0.5 g/kg, 1.0 g/kg, and 2.0 g/kg groups). CONCLUSION: Oyster peptide could improve the structures of immune organs of the CTX-induced immunosuppressed mice, recover the imbalances of T lymphocyte subsets, improve the immune cytokines and increase numbers of nucleated cells and DNA content in bone marrow, thus improving the immunologic function.