ABSTRACT
Objective To study the role of complement C3a receptor (C3aR) in cognitive impairment in rats with sepsis induced by cecal ligation and puncture (CLP), and to explore the possible mechanism. Methods Totally 132 rats were randomly divided into sham operation group (sham group) and sepsis group (CLP group). The initial number of each group was 66 animals, and 22 animals were set at each time point. The SD rat CLP animal model was constructed, and serum and brain (hippocampus and prefrontal cortex) samples were collected at day 1, day 15 and day 30 after operation. The levels of tumor necrosis factor-α(TNF-α), interleukin-1β (IL-1β) and IL-6 in the samples were determined by ELISA. Western blotting detected Tau protein (Tau), phosphorylated Taup-Tauand C3aR expression in brain samples. Totally 66 rats were randomly divided into 3 groups, sham operation group, CLP group and C3aR antagonist(C3aRa) intervention group. On 15th, 17th, and 19th days after CLP, C3aRa intervened in rats, and they received inhibition avoidance test and object recognition test 30 days after CLP. The expressions of C3aR, lonized calcium binding adapter molecule 1(Iba1), GFAP and p-Tau in the hippocampus were detected by immunofluorescence. Results Compared with the sham group, the serum and brain tissue (TNFα, IL-1β and IL-6) of rats in the CLP group first increased and then decreased within 30 days after CLP. In the hippocampus and prefrontal cortex of CLP group, Tau phosphorylation was significantly enhanced at day 30 and day 1 and 15 after surgery, respectively (P<0.05). Compared with the sham group, C3aR protein levels in hippocampus and prefrontal cortex of rats in CLP group increased significantly at day 15 and 30 after operation (P<0.05). Compared with the CLP group, the endogenous C3aR content decreased significantly after C3aRa intervention (P<0.05), and Iba1, GFAP and p-Tau immunostaining were significantly inhibited (P<0.05). The C3aRa intervention in CLP rats reversed the cognitive impairment. Conclusion C3aR plays an important role in the development of biochemical and behavioral changes commonly associated with the onset of sepsis-induced neurodegenerative processes. C3aRa can be injected into the hippocampus to counteract the neurodegenerative process induced by sepsis.
ABSTRACT
The present study was aimed to observe the characteristics of sublingual microcirculation and the changes of humoral factors in healthy people of three different high altitude populations. Three groups of healthy subjects in Guoluo area of Qinghai province (4 100 m) were included: Tibetan group: 30 Tibetans, (45.62 ± 10.15) years old; Han group: 22 two-generation of Han immigrants, (46.23 ± 8.59) years old; migrant group: 23 migrants living at high altitude for 2-5 years, (43.45 ± 8.31) years old. Blood routine test was performed to determine white blood cell (WBC) count, red blood cell (RBC) count, hemoglobin (HGB), hematocrit (HCT), platelet (PLT) count, and neutrophil (NEUT) count. The changes of serum humoral factors including endothelin-1 (ET-1), CD31, CD34, CD105, vascular endothelial growth factor (VEGF), nitric oxide (NO) and noradrenaline (NE) were detected by ELISA. Continuous noninvasive hemodynamics monitor was used to continuously measure the changes of systemic circulation indexes: cardiac output (CO), cardiac index (CI), heart rate (HR), stroke volume (SV), pulse pressure variation (PPV), systemic vascular resistance index (SVRI), and mean arterial pressure (MAP). Blood oxygen was measured by pulse oximeter. Sublingual microcirculation indexes including total vascular density (TVD), perfused vessel density (PVD), proportion of perfused vessels (PPV), and microvascular flow index (MFI) were determined by sidestream dark field imaging. The results showed that there were no difference in systemic circulation among the 3 groups. Compared with Tibetan group, TVD and PVD of microcirculation in Han group and migrant group were significantly increased (P < 0.05). Compared with Tibetan group and Han group, WBC, RBC, HGB and HCT of migrant group were significantly increased (P < 0.05). Compared with Han group and Migrant group, PLT of Tibetan group was significantly increased (P < 0.05). Compared with the Tibetan group, the levels of serum humoral factors CD105 and VEGF were significantly higher in the migrant group (P < 0.05), while compared with Han and migration groups, NO in Tibetan group was significantly increased (P < 0.05). It is suggested that there were significant differences in microcirculation (TVD, PVD), blood routine (WBC, RBC, HGB, HCT) and humoral factors (CD105, VEGF) among different populations in high altitude area. Importantly, the increased microcirculation, erythrocytosis and increased pro-angiogenic factors due to hypoxic environment were observed in long-term residents and migrants, except for permanent residents. These physiological changes have clinical significance in the treatment of septic shock and chronic altitude sickness for different plateau populations.