Objective:To establish pig cardiac arrest resuscitation model, and explore the effect of automatic compression synchronous ventilation (ACSV) on cardiopulmonary resuscitation in pigs.Methods:Twelve male white pigs with body weight of (38±3) kg were divided into ACSV group and intermittent positive pressure ventilation (IPPV) group with 6 pigs in each group by random number table method. A porcine cardiac arrest and resuscitation model was prepared with ventricular fibrillation induced by alternating current release via right ventricular electrode for 6 min and compression for 8 min. Mechanical chest external compression depth 5 cm, frequency 100 times/min. The tidal volume of ACSV group was 3 mL/kg and the frequency was 100 times/min. In the IPPV group, the tidal volume was 7 mL/kg and the frequency was 10 times/min. Arterial blood was drawn before resuscitation and at 1, 4 and 7min during resuscitation for blood gas analysis. Coronary perfusion pressure (CPP), end-respiratory carbon dioxide (ETCO 2) and carotid blood flow (CBF) were monitored during resuscitation. Stroke volume (SV) and global ejection fraction (GEF) were recorded by pressure monitoring catheter before and 1, 2 and 4 h after resuscitation. Venous blood samples were collected at each time point and 24 h after resuscitation to detect cardiac troponin I (cTnI), neuron specific enolase (NSE), alamine aminotransferase (ALT), creatinine (Cr), and intestinal fatty acid binding protein (IFABP). Results:(1) During resuscitation, CPP, ETCO 2 and CBF in ACSV group were slightly higher than those in IPPV group, but the differences between groups were not statistically significant. (2) There was no significant difference in pH, PaCO 2, HCO 3- and lactic acid between the two groups during resuscitation. The PaO 2 in ACSV group was higher than that in IPPV group, and the difference was statistically significant at 4 and 7 min. (3) The success rate of resuscitation in both groups was 83.3%, and there was no significant difference in SV and GEF before and after resuscitation. (4) After resuscitation, cTnI, NSE, ALT, Cr, iFABP and other indexes in ACSV group were lower than those in IPPV group, and there were statistically significant differences in cTnI at 24 h after resuscitation, ALT at 2 h and 24 h after resuscitation, and IFABP at 4 h and 24 h after resuscitation (all P<0.05). Conclusions:This study preliminarily suggested that the novel ACSV could significantly improve the oxygen supply level during cardiopulmonary resuscitation in pigs, while keeping the compression efficiency unchanged, avoiding hyperventilation, and reducing multiple organ damage after resuscitation, which is worthy of further study.

With basal medium, we studied the growth status, lipid droplet distribution, total lipid content of Chlorella protothecoides CS-41 treated with different concentrations of sodium chloride (0, 150, 300 and 600 mmol/L) by optical microscopy, electron microscopy, confocal laser focusing and Nile red staining. Results show that the addition of NaCl affected the growth of Chlorella protothecoides CS-41. With the increase of NaCl concentration, the growth rate of Chlorella was inhibited. Chlorella cell wall became thicker, and lipid droplets increased. At the early stage, the amount of lipid droplets in the 600 mmol/L NaCl culture was the highest, but at the late-log stage, the amount of lipid droplets increased with the increase of the biomass of culture in 150 and 300 mmol/L NaCl culture. At the stable stage, biomass (dry weight) in 300 mmol/L NaCl culture was 73.55% of that in the control, but the total lipid content was 2.22 times higher than that in the control. A certain concentration of sodium chloride treatment can significantly increase the lipid content of Chlorella protothecoides CS-41.

Orthodontic tooth movement elicits alveolar bone remodeling and orofacial pain that is manifested by tooth mechanical hyperalgesia. Nerve growth factor (NGF) is upregulated in periodontium and may modulate tooth mechanical hyperalgesia. The objectives were to examine the role of NGF in tooth mechanical hyperalgesia and to elucidate the underlying mechanisms. Tooth mechanical hyperalgesia was induced by ligating closed coil springs between incisors and molars in Sprague-Dawley rats. Retrograde labeling was performed by periodontal administration of fluor-conjugated NGF and the detection of fluorescence in trigeminal ganglia (TG). Lentivirus vectors carrying NGF shRNA were employed to knockdown the expression of NGF in TG. The administration of agonists, antagonists, and virus vectors into TG and periodontium was conducted. Tooth mechanical hyperalgesia was examined through the threshold of biting withdrawal. Our results revealed that tooth movement elicited tooth mechanical hyperalgesia that could be alleviated by NGF neutralizing antibody and that NGF was upregulated in periodontium (mainly in periodontal fibroblasts) and TG. Retrograde labeling revealed that periodontal NGF was retrogradely transported to TG after day 1. Acid-sensing ion channel 3 (ASIC3) and NGF were co-expressed in trigeminal neurons and the percentage of co-expression was significantly higher following tooth movement. The administration of NGF and NGF neutralizing antibody into TG could upregulate and downregulate the expression of ASIC3 in TG, respectively. NGF aggravated tooth mechanical hyperalgesia that could be alleviated by ASIC3 antagonist (APETx2). Moreover, NGF neutralizing antibody mitigated tooth mechanical hyperalgesia that could be recapitulated by ASIC3 agonist (GMQ). NGF-based gene therapy abolished tooth mechanical hyperalgesia and downregulated ASIC3 expression. Taken together, in response to force stimuli, periodontal fibroblasts upregulated the expressions of NGF that was retrogradely transported to TG, where NGF elicited tooth mechanical hyperalgesia through upregulating ASIC3. NGF-based gene therapy is a viable method in alleviating tooth-movement-induced mechanical hyperalgesia.