Objective To explore the role and mechanism of mechanically sensitive ion channel Piezo2 in mechanical allodynia of rats with low back pain induced by simulating the low-frequency vibration of a helicopter.Methods Low-frequency vibration(LFV)model with 3-dimensional 6 degrees of freedom was used to induce low back pain in awake rats in a sitting position.Twenty-four male SD rats(8 weeks old)were randomly divided into control(Ctrl)group and LFV group.HE staining was used to evaluate the injury of the multifidus muscle.Von Frey test was carried out to detect pain sensitivity.Open field test was employed to assess the spontaneous activity and anxiety.ELISA,Western blotting and immunofluorescence staining were performed to detect the expression of NGF,TrkA and downstream molecule Piezo2.Dorsal root ganglia(DRG)neurons was isolated from SD rats and primarily cultured.After identified with immunofluorescence staining,the neurons were divided into the Ctrl group,the LFV group,and the LFV+D-GsMTx4(D-G4,an Piezo2 channel antagonist)group.Western blotting was used to detect the protein expression of Piezo2,and a calcium ion fluorescent probe was utilized to detect the intracellular Ca2+.The DRG neurons were pretreated with 50 ng/mL NGF for 1 h.Calcium ion fluorescent probe was used to observe the changes in intracellular Ca2+in the LFV group,the LFV+NGF group,and the LFV+NGF+D-G4 group.Results The rats of the LFV group showed abnormal morphology in multifidus muscles,accompanied with inflammatory cell infiltration,decreased paw withdrawal reflex threshold(P<0.05),and shortened total active time and active time in the centre,and decreased distance traveled in the centre(P<0.05),while prolonged total stationary time,stationary time in the periphery,and increased distance traveled in the periphery(P<0.05),and moreover,enhanced expression of Piezo2,NGF and TrkA in the DRG tissues(P<0.05).Cell experiments showed that compared with the Ctrl group,the expression of Piezo2 in the neurons was increased(P<0.05),and the intracellular Ca2+level was significantly elevated in the LFV group(P<0.05).Compared with the LFV group,the Ca2+level was higher in the LFV+NGF group(P<0.05),and the sensitization effect of NGF on Piezo2 was reversed after D-G4 treatment(P<0.05).Conclusion Sustained low-frequency vibration induces low back pain and mechanical allodynia in rats through the NGF-TrkA/Piezo2 pathway.

Objective To determine the effects of treadmill training on the structure of hippocampal myelin and cognitive function in rats exposed to acute plateau hypoxia.Methods With 30 SPF-grade female SD rats (aged 6-8 weeks,weighing 200-220 g),6 of them were used for observation of myelin structure after injury,and the remaining 24 rats were randomly divided into control group,hypobaric hypoxia group and treadmill training group (n=8).The rats in above experimental groups were placed in a low-pressure oxygen chamber at an altitude of 6000 m for 7 consecutive days,and the rats of the control group were placed in the confined chamber for the same period without hypoxia.Then,the rats of the treadmill training group received a 4-week treadmill training scheme since the day after hypoxia.Finally,all the rats were tested for cognitive function with open field test (OFT)and Morris water maze (MWM).Transmission electron microscopy (TEM) was used to observe the changes of demyelination in the hippocampus. The expression of oligodendrocyte transcription factor 2 (Olig2)and myelin basic protein (MBP )in the hippocampal CA1 and CA3 regions was measured by immunofluorescence staining and Western blotting.Results Behavioral tests showed that the number into the central area,total distance,distance ratio in OFT and the number of platform crossings and distance to the target area in MWM were reduced in the hypobaric hypoxia group than the control group (P<0.05 ),while these indexes were increased in the treadmill training group than in the hypobaric hypoxia group (P<0.05).Immunofluorescence staining indicated that the number of Olig2 positive cells per unit area and the mean fluorescence intensity of MBP in the CA1 and CA3 regions were significantly lessen in the hypobaric hypoxia group than the control group (P<0.05 ),while these indicators were higher in the treadmill training group than the hypobaric hypoxia group (P<0.05 ).Western blotting displayed that the expression levels of Olig2 and MBP in the hippocampus were obviously lower in the hypobaric hypoxia group than the control group (P<0.01 ),while the levels were increased in the treadmill training group than the hypobaric hypoxia group (P<0.01 ).Conclusion Treadmill training promotes the number of the oligodendrocyte spectrum cells in CA1 and CA3 regions,enhances the expression of myelin-related proteins and improves myelin repair in hippocampus of hypobaric hypoxia rats,and thereby ameliorates hypoxia-induced anxiety-like behaviors and memory dysfunction.

Objective:To explore the changes in the proportion and number of T cell subsets in different immune organs during sepsis.Methods:Eight-week-old female C57BL/6 mice were randomly divided into sepsis group and sham group.The experimental sepsis model was constructed through cecal ligation and puncture, and the sham group just underwent sham operation.Then we detected the changes in the total number of lymphocytes and in the ratio and absolute number of CD4 + T cells, CD8 + T cells, CD4 + CD25 high Foxp3 + regulatory T cells(Treg) and CD4 + CD25 low Foxp3 - effector T cells(Teff) in the mouse spleen, axillary and inguinal lymph nodes and bone marrow by cell counting and flow cytometry 24 h and 16 d after modeling. Results:In the spleens of septic mice, the ratio and absolute numbers of CD4 + T cells and Teff, as well as the absolute number of CD8 + T cells were significantly reduced 24 h and 16 d after modeling.There was no significant change in the number of Treg 24 h after modeling, but a significant increase occurred 16 d after modeling.During sepsis, the changes of CD4 + T cells, CD8 + T cells and Teff in mouse lymph nodes were basically the same as those in the spleen; but the changes in Treg were different, with no significant change in the early stage and a significant decrease in the late stage.In addition, the absolute numbers of CD4 + T cells, CD8 + T cells, and Teff in the bone marrow did not change significantly in the 24 h model, but decreased significantly in the 16 d model.The proportion and absolute number of Treg during sepsis were significantly reduced. Conclusion:During different periods of sepsis, there is a large consumption of lymphocytes in the spleen, lymph nodes and bone marrow.In most cases, the trend of Treg changes is inconsistent or even opposite to that of other T cell subsets.There are differences in the changes of T cells among major immune organs, suggesting that the responses of different immune organs to sepsis are heterogeneous.

Due to incomplete function of gastrointestinal barrier, children are more likely to develop gastrointestinal dysfunction.The clinical application of related biomarkers helps early diagnosis and treatment of gastrointestinal dysfunction in children.By sorting out the studies in recent years, we explored the relationship between inflammatory indicators, intestinal epithelial barrier damage biomarkers, immunological biomarkers, gut microbiome and gastrointestinal dysfunction, and summarized the main problems and solutions faced in the research, which may help the screening, identification and clinical application of relevant biomarkers in subsequent research.

Objective:To clarify the changes in the bone marrow vascular system in the early stage of sepsis in animal model.Methods:A sepsis mouse model was established by cecal ligation and puncture (CLP), and HE staining, immunofluorescence staining, flow cytometry and real-time quantitative PCR were used to comprehensively analyze the varieties of bone marrow vascular system in structure, the relative proportion of vascular endothelial cells and the expressions of damage-related genes at mRNA level.Results:A series of adaptive changes occurred in the bone marrow vascular system in the early stage of sepsis.Histological analysis showed that the bone marrow vascular structure was significantly remodeled.The average density of bone marrow sinusoids in the CLP group was (410.43±72.63)counts/mm 2, which was significantly higher than that in the sham group[(294.43±68.94)counts /mm 2, P<0.01]. The area of luminal pixels accounted for (43.46±3.21)%, which was significantly higher than that in the sham group[(30.28±4.44)%, P<0.001]. The exudation amount of evans blue in the bone marrow tissue of the CLP group was (0.42±0.12)ng/mg tissue, which was significantly higher than that in the sham group[(0.24±0.09)ng/mg tissue, P<0.05], suggesting increased vascular permeability.The results of flow cytometry analysis showed that the EC in bone marrow of the CLP group mice was in a proliferative state, with the proportion of Ki67 + endothelial cell increasing[(1.91±0.65)% vs.(5.06±1.10)%, P<0.01]. The mRNA levels of some genes related to the activation of vascular endothelial cells were up-regulated. Conclusion:Sepsis changes the structure and function of the bone marrow vascular system, and has a significant impact on the bone marrow microenvironment.

Objective:To study and analyse the results of postoperative hemorrhage after laparoscopic pancreaticoduodenectomy (LPD).Methods:The clinical data of patients who underwent LPD from May 2011 to December 2019 at Hunan Provincial People's Hospital were retrospectively analyzed. The clinical characteristics of patients, onset time of postoperative hemorrhage, location of postoperative hemorrhage, postoperative biliary fistula, pancreatic fistula, infection and other short-term complications, reoperation and mortality rates were analyzed.Results:Of 356 patients who underwent LPD in this study, there were 200 males and 156 females, aged (58.0±10.5) years. The postoperative complication rate was 33.1% (118/356), the reoperation rate was 6.5% (23/356), and the mortality rate was 2.5% (9/356). The most common complications were postoperative hemorrhage [15.2% (54/356)], pancreatic fistula [14.6%(52/356)] and abdominal infection [13.8%(49/356)]. The onset time of postoperative hemorrhage was usually in the 1st - 14th day, and the highest rate of postoperative hemorrhage was 3.9% (14/356) on the first day after surgery. The postoperative hemorrhage rate then showed a downward trend, but increased again on the 7th day. The extraluminal hemorrhage locations were relatively widely distributed, and the incidence of gastrointestinal anastomotic hemorrhage in patients with intraluminal hemorrhage was the highest [67.9%(19/28)]. Of the 9 patients who died, 7 were related to postoperative bleeding.Conclusions:LPD resulted in a high incidence of complications. Postoperative hemorrhage was a complication that had the greatest impact on short-term recovery of patients. It was also an important cause of reoperation and death. In addition to postoperative bleeding caused by pancreatic fistula, gastrointestinal anastomotic bleeding was also clinically important.

Sepsis is a common critical illness in clinic and a worldwide serious public health issue.Regulatory T cell(Treg) is a type of negative immune-regulatory cell that can affect the organism immune status through various pathways to inhibit inflammation.Mastering the research progress in related fields of Treg is of great significance for further understanding the pathogenesis of sepsis and exploring new diagnostic and therapeutic methods for sepsis.This review provided the recent research progress of Treg cells in sepsis.

Sepsis is a common clinical critical illness and causing serious public health problem worldwide. Lipopolysaccharide(LPS) release from the cytoderm of Gram-negative bacteria and is a pivotal initiating factor in the development of sepsis,which can induce pathological processes such as inflammation, coagulopathy and immunosuppression. Therefore,the research progress in LPS-related region is of great sig-nificance for understanding the pathogenesis of sepsis and developing new diagnostic and therapeutic methods for sepsis. This review summarized the related research progress of LPS and sepsis based on the recent litera-tures.

Sepsis is a common critical disease, the morbidity of sepsis increases in recent years. Interleukin( IL)-6 plays an important role in the progress of sepsis. It can induce inflammation and cause coagulation. Therefore,it is particularly important to study the relationship between sepsis and IL-6. In order to provide more direction and ideas for septic treatment,this paper summarized the related research progress of IL-6 and sepsis based on the recent literature.

Objective To investigate the expressions of interleukin-33 (IL-33),soluble growth stimulation expressed gene 2 (sST2) and transforming growth factor β1 (TGF-β1) in the patients with systemic sclerosis (SSc) and their correlations.Methods Serum IL-33,sST2 and TGF-β1 levels from 25 SSc patients and 25 healthy controls were determined by an enzyme linked immunosorbent assay (ELISA).The expressions of IL-33 in the damaged skin tissue of SSc patients and normal skin tissue were detected with the immunohistochemical staining.Results Serum IL-33 and TGF-β1 levels in SSc patients were significantly higher than that in healthy controls (P ＜ 0.05),and serum IL-33 levels were positively correlated with TGF-β1 levels in SSc patients (P ＜ 0.05).Immunohistochemical staining results showed that the expression level of IL-33 in the damaged skin tissue of SSc patients were significantly higher than that in normal skin tissue (P ＜ 0.05).However,there was no significant difference in the expression level of sST2 between SSc patinets and healthy controls.Conclusion Serum IL-33 levels in SSc patients increase significantly,which is correlated with the expression of TGF-β1,indicating that IL-33 may play an important role in the process of inflammation and fibrosis of SSc via the regulation of TGF-β1.