Objective:To study the effect of different doses of 60Co γ-ray ionizing radiation on mitochondrial function in mouse hematopoietic stem and progenitor cells (HSPCs). Methods:C57BL/6 mice were divided into control group, 1 Gy irradiation group and 4.5 Gy irradiation group. The mitochondrial functions were detected at 12 h and 24 h after irradiation, including ROS level, membrane potential, mitochondrial structure, and mitochondrial stress. Bone marrow c-Kit + cells received a single 15 Gy irradiation in vitro, after 24 h, mitochondrial function was detected. Results:It was found that mice leukocytes ( t=12.41, 18.31, 16.48, 14.16, 19.08, 20.25, P<0.05), red blood cells ( t=4.81, 6.62, P<0.05) and platelets ( t=4.33, 6.68, P<0.05) were significantly reduced. The numbers of bone marrow colony formation unit ( t=16.27, 55.66, 17.06, 43.75, P<0.05), and HSPCs ( t=5.16, 11.55, P<0.05) were decreased dose-dependently post-irradiation. Under 1 Gy irradiation, the mitochondrial function and mitochondrial basal metabolic index of HSPCs ( t= 7.36, 3.68, 4.58, 3.15, 3.15, P<0.05) were enhanced at 24 h post-irradiation. Under 4.5 Gy irradiation, mitochondrial number, mitochondrial membrane potential ( t=12.29, 10.46, P<0.05), maximal respiration and spare respiratory capacity were decreased ( t=7.81, 5.78, 6.70, 5.83, P<0.05), ROS level was increased ( t=4.63, 4.12, P<0.05). The basal respiration and oxidative phosphorylated ATP production were reduced at 12 h after irradiation ( t=8.48, 3.80, P<0.05); and the proton leakage was increased ( t=6.57, P<0.05) and coupling efficiency was reduced ( t=11.43, P<0.05) at 24 h after irradiation. In cultured c-Kit + cells, the level of ROS ( t=11.30, P<0.05) and the maximum respiration and spare respiratory capacity were increased ( t=4.25, 3.44, P<0.05) while the mitochondrial membrane potential was decreased ( t=34.92, P<0.05) significantly. Conclusions:A method for systematically assessing mitochondrial function in HSPCs was established, and the effect of ionizing radiation on mitochondrial function of HSPCs was clarified, laying a foundation for further revealing the mechanism of ionizing radiation-induced mitochondrial damage in HSPCs.

Objective:To investigate the difference in the radiation sensitivity of hematopoietic stem and progenitor cells (HSPCs) derived from fetal liver and bone marrow.Methods:HSPCs from fetal liver of 14.5 d embryo or bone marrow of 8 week-old mice were isolated to receive a single dose of 5 or 10 Gy irradiation in vitro using a 60Co irradiator. Twelve hours later, the cell apoptosis, mitochondrial reactive oxygen species (ROS) level, colony formation ability and DNA damage in HSPCs were detected. Freshly isolated HSPCs were injected into lethally irradiated CD45.1 + C57BL/6J mice (4.5 Gy+ 5 Gy with an interval of 30 min) Chimerism rate, lineage constitution, and cell cycle were analyzed 12 weeks after transplantation. Results:Compared with bone marrow HSPCs after irradiation, the percentage of apoptosis in fetal liver HSPCs was significantly higher ( t=16.21, 12.27, P<0.05), the level of ROS was dramatically elevated ( t=68.72, 18.89, P<0.05). At 10 Gy, fetal liver HSPCs could not form colonies at all ( t=12.41, 15.67, 9.46, P<0.05). γ-H2AX immunofluorescence staining showed that the DNA damage of fetal liver HSPCs was more severe after irradiation, and the number of Foci formed was significantly higher than that of bone marrow HSPCs ( t=2.27, 2.03, P< 0.05), which indicated that fetal liver HSPCs were more sensitive to radiation. The chimerism rate of transplanted fetal liver HSPCs was lower than that of bone marrow cells ( t=5.84, P<0.05) with a higher proportion of myeloid lineage, suggesting that fetal liver HSPCs had lower in vivo reconstitution capacity than bone marrow HSPCs and were more prone to myeloid differentiation. The cell cycle of bone marrow HSPCs from transplanted chimeric mice was examined, and the proportion of S-phase was significantly higher in the fetal liver group than that in the bone marrow group ( t=2.89, P<0.05). Mitochondrial stress results showed that fetal liver HSPCs had higher basal respiratory capacity ( t=39.19, P<0.05), proton leakage ( t=6.64, P<0.05), ATP production ( t=9.33, P<0.05), and coupling efficiency ( t=7.10, P<0.05) than bone marrow c-Kit + cells, while respiratory reserve capacity ( t=5.53, P< 0.05) was lower than that of bone marrow c-Kit + cells. Conclusions:HSPCs derived from fetal liver display higher radiosensitivty compared with bone marrow HSPCs, laying the foundation for an in-depth illustration of the effects of radiation on hematopoietic stem cells at different developmental stages.

Objective: To investigate the effect of hypertensive disorder complicating pregnancy (HDCP) on the mortality and early complications of premature infants. Methods: The general clinical data of preterm infants with gestational age 24-36^{+ 6} weeks were collected from the cooperative units in the task group from January 1, 2013 to December 31, 2014.According to the severity of HDCP, the infants were divided into 4 groups: HDCP group, preeclampsia group, eclampsia group and non HDCP group, the mortality and major complications of preterm infants were compared, and the influencing factors were analyzed. Results: The mortality rate of preterm in the HDCP group was significantly higher than that of non HDCP group, and there was statistical significance (χ²=9.970, P=0.019). Eclampsia had a highest fatality rate (4.8%) in the early stage, compared with non HDCP group (2.2%), and the difference was statistically significant.Comparison of HDCP group (1.8%) and eclampsia group (3.2%) suggested that there was no statistically significant difference.The incidence of respiratory distress syndrome (RDS) in preterm in HDCP group was significantly higher than that of non HDCP group, and there was statistical significance (χ²=13.241, P=0.004). Eclampsia group showed the highest incidence (35.4%), compared with non HDCP group (16.2%), the difference was statistically significant, but compared with HDCP group (19.9%), preeclampsia group (17.1%), there was no significant diffe-rence.The incidence of bronchopulmonary dysplasia (BPD) in preterm in HDCP group was significantly higher than that of non HDCP group (χ²=9.592, P=0.022), the highest incidence showed up in eclampsia group (9.7%), compared with non HDCP group (2.0%) and HDCP group (1.7%), the difference was statistically significant.But there was no statistically significant difference, compared with preeclampsia group.As the degree of HDCP aggravated, the incidence of BPD gradually rose.There was no significant impact on necrotizing enterocolitis (NEC), retinopathy of prematurity (ROP), intraventricular hemorrhage (IVH) and sepsis of HDCP (χ²=7.054, 7.214, 0.358, 3.852; P=0.070, 0.065, 0.949, 0.278). Considering the overall outcome of the child, that was, whether the child died or survived, he had at least one complication, and HDCP had an effect on it (χ²=15.697, P=0.001), so the incidence increased while the degree of HDCP rose gradually.After adjusting gestational age, birth weight, sex, way of delivery, placental abruption and front placenta, prenatal hormonal, gestational diabetes, neonatal asphyxia and other factors, the results displayed that HDCP was the factor leading to the death of premature baby (OR=2.159, 95%CI: 1.093-4.266), and comparison between preeclampsia and eclampsia showed no statistical difference (P=0.714, 0.389); HDCP had no significant influence on RDS, BDP, ICH, NEC, ROP and sepsis. Conclusions HDCP leads to increased risk of premature death, but also leads to the increased incidence of RDS and BPD, but it had no obvious effect on NEC, ROP, IVH, sepsis and other complications.