OBJECTIVE: To investigate the mechanism of autophagy in regulating bacterial translocation in intestinal infection caused by hypervirulent Klebsiella pneumonia (hvKp) and explore the method of reducing translocation infection of intestinal bacteria. METHODS: Fifty C57BL/6J mice were divided into gavage group (n = 40) and control group (CO group, n = 10). The gavage group was orally administered with 200 μL/d of hvKp (colony count of 10⁹ CFU/mL) continuously for 5 days to establish a hvKp intestinal infection model. CO group was given an equal amount of normal saline. After the experiment, the mice were anesthetized with lsofluraneand euthanized with cervical dislocation under anesthesia. Peripheral venous blood of mice was collected to detect bacterial translocation by 16S rDNA sequencing, then divided into translocation group (BT+ group) and non-translocation group (BT- group). Hematoxylin-eosin (HE) staining was used to evaluate intestinal morphology. The ultrastructural changes of intestinal tissues were observed by electron microscope. The levels of intestinal oxidative stress indicators such as superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione peroxidase (GPx) were measured. Translocation was detected by in situ hybridization. The expression of tight junction protein microtubule-associated protein 1 light chain 3-II (LC3-II) and autophagy protein Beclin-1 were measured by Western blotting. The mRNA expression of tight junction proteins ZO-1 and Claudin-2 were detected by reverse transcription-polymerase chain reaction (RT-PCR). The expression of autophagy protein and tight junction protein were observed by immunofluorescence. RESULTS: Two out of 40 mice in the gavage group died after developing aspiration pneumonia. All mice in the CO group survived. The 16S rDNA sequencing results showed that no bacteria were detected in the peripheral blood of the CO group, but bacteria were detected in the peripheral blood of 18 mice in the gavage group, with a bacterial translocation rate of 47.4%. The BT- and BT+ groups showed intestinal mucosal tissue damage, with severe damage in the BT+ group. Compared with the CO group, the level of MDA in the BT- and BT+ groups were significantly increased, while the activities of SOD and GPx were significantly decreased. Compared with the BT- group, the MDA level in the BT+ group further increased, while the SOD and GPx activities further decreased [MDA (mmol/mg): 2.98±0.11 vs. 2.48±0.11, SOD (U/mg): 62.40±5.45 vs. 73.40±4.08, GPx (U/mg): 254.72±10.80 vs. 303.55±8.57, all P < 0.01]. The results of in situ hybridization detection showed that after continuous gastric lavage for 5 days, displaced hvKp was detected in the intestinal mucosal lamina propria and liver tissue of the BT+ group. Compared with the CO group, the protein expressions of LC3-II and Beclin-1 in the BT- and BT+ groups were significantly increased. The protein expressions of LC3-II and Beclin-1 in the BT+ group were obviously lower than those in the BT- group (LC3-II/β-actin: 0.38±0.04 vs. 0.70±0.09, Beclin-1/β-actin: 0.62±0.05 vs. 0.86±0.05, both P < 0.01), and there were autophagosomes in the intestinal mucosa. These results indicated that intestinal mucosal autophagy was activated after hvKp continuous gavage. Compared with CO group, the mRNA expressions of ZO-1 and Claudin-2 in the BT- and BT+ groups were significantly decreased. Compared with the BT- group, the mRNA expressions of ZO-1 and Claudin-2 in the BT+ group was further reduced [ZO-1 mRNA (2^-ΔΔCT): 0.78±0.06 vs. 0.88±0.06, Claudin-2 mRNA (2^-ΔΔCT): 0.40±0.04 vs. 0.70±0.06, both P < 0.01]. The immunofluorescence results showed that the fluorescence intensity of LC3-II, Beclin-1, ZO-1, and Claudin-2 in the BT+ group was significantly lower than that in the BT- group. CONCLUSION HvKp can activate intestinal mucosal autophagy and reduce the damage to intestinal mucosal barrier function by down-regulating oxidative stress level, reduce the occurrence of bacterial translocation.
Animals ; Oxidative Stress ; Mice, Inbred C57BL ; Autophagy ; Intestinal Mucosa/microbiology* ; Bacterial Translocation ; Mice ; Klebsiella Infections/microbiology* ; Superoxide Dismutase/metabolism* ; Beclin-1

Objective To identify the reasons and treatment strategies of epidural fluid collection (EFC) secondary to cranioplasty in patients with traumatic brain injury after decompressive craniectomy.Methods From June 2013 to July 2017,a retrospective analysis was performed on clinical data of 150 patients with traumatic brain injury after decompressive craniectomy in our hospital.A total of 47 patients experienced EFC following cranioplasty and 103 not.Risk factors of EFC after cranioplasty were analyzed by multiple factor Logistic regression.Results For the 47 EFC patients,32 patients had no obvious clinical symptoms and EFC was absorbed gradually through conservative therapy;15 patients had clinical symptoms,such as mental deterioration,headache,or limb weakness.EFC disappeared through vacuation in 4 patients and subcutaneous drainage in 11.The proportions of patients with skull defect＞80 cm2,dural defect and dural calcification in patients with EFC were significantly higher as compared with those without EFC (P＜0.05).Multiple factor Logistic regression analysis showed that skull defect＞80 cm2 and dural mater calcification were independent risk factors for EFC after cranioplasty.Conclusions Patients with large skull defect＞80 cm2 and dural calcification are prone to have EFC after cranioplasty.Careful evaluation of imaging data,good surgical skills and strengthening postoperative management can reduce incidence of EFC after cranioplasty.

BACKGROUND:Bone marrow mesenchymal stem cel s transplantation can inhibit experimental emphysema inflammatory reaction and apoptosis, and has been experimental y confirmed to treat severe lung function impairment. OBJECTIVE:To explore the inhibitory effects of bone marrow mesenchymal stem cel s transplantation via different ways on inflammatory reaction and apoptosis due to experimental emphysema. METHODS:Female Wistar rats were randomly divided into control group, intravenous group and endotracheal group fol owing model establishment using fumigation plus intratracheal instil ation of porcine pancreatic elastase. In the latter two groups, bone marrow mesenchymal stem cel s from male rats were injected via the tail vein and the trachea, respectively. In the control group, rats were given PBS via he tail vein and trachea. At 14 days after transplantation, pathological changes of rat lung tissues were observed, cel apoptotic index in alveolar wal cel s and tumor necrosis factorαlevel in the bronchoalveolar lavage fluid were detected. RESULTS AND CONCLUSION:Compared with the control group, in the intravenous and endotracheal groups,the pathological changes of lung tissues were relieved, tumor necrosis factorαlevel and apoptosis index were reduced significantly (P<0.01);but there were no differences between the intravenous and endotracheal groups (P>0.05). These findings indicate that bone marrow mesenchymal stem cel s transplantation via the tail vein and trachea both can exert obvious therapeutic effects on emphysema. Moreover, cel transplantation via the tail vein is more convenient and easier than that via the trachea in the treatment of emphysema.

BACKGROUND:Bone marrow mesenchymal stem cells transplantation can change the surrounding microenvironment through paracrine mechanisms, and can be employed for treatment of serious damage to lung function through the promotion of angiogenesis, inhibition of apoptosis and maintaining functional stability of autonomic nervous system. OBJECTIVE:To observe the inflammatory reaction in experimental emphysema and inhibition of apoptosis through bone marrow mesenchymal stem cells transplantation.
METHODS:Twenty-four Wistar female rats were randomly divided into three groups:healthy control group, model group and experimental group. In the latter two groups, smoking and endotracheal instil ation of porcine pancreatic elastase were performed to establish emphysema models. After modeling, bone marrow mesenchymal stem cells were injected via tail vein in the experimental group. Pathological changes of the lung, the level of tumor necrosis factor-alpha and cellnumber in the bronchoalveolar lavage fluid as wel as apoptotic index in lveolar wal s were detected after celltransplantation.
RESULTS AND CONCLUSION:In the model and experimental groups, pathological changes of lung tissues were observed to different extent. The lung pathological changes were slighter in the experimental group than the model group (P<0.01). The level of tumor necrosis factor-alpha and apoptotic index in lung tissue were lower in the experimental group than the model group (P<0.01). These findings indicate that bone marrow mesenchymal stem cells can improve emphysema pathological y through inhibition of inflammatory response and apoptosis in experimental emphysema.