Recombinant protein EBI3 attenuates Clonorchis sinensis-induced liver fibrosis by inhibiting hepatic stellate cell activation in mice.

BACKGROUND: Chronic infection with Clonorchis sinensis can cause hepatobiliary fibrosis and even lead to hepatobiliary carcinoma. Epstein-Barr virus-induced gene 3 protein (EBI3) is a subunit of interleukin 35, which can regulate inflammatory response and the occurrence of fibrotic diseases. Previous studies have reported that the expression of EBI3 in the serum of patients with liver cirrhosis is reduced. The present study aims to investigate the biological effects of EBI3 on liver fibrosis caused by C. sinensis and the underlying molecular mechanisms. METHODS: We first established a mouse model of liver fibrosis induced by C. sinensis infection and then measured the serum expression of EBI3 during the inflammatory and fibrotic phase. GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analyses were performed to investigate the potential role of EBI3 in liver fibrosis by regulating the extracellular matrix structural constituent and collagen catabolic process. Recombinant protein EBI3 (rEBI3) was added to hepatic stellate cells (HSCs) in vitro with C. sinensis antigen to explore its function. Finally, the therapeutic effect of rEBI3 was verified by intravenous injection into C. sinensis-infected mice. RESULTS: The results showed that the serum expression of EBI3 increased in the inflammatory response phase but decreased in the fibrotic phase. The excretory-secretory products of C. sinensis (Cs.ESP) were able to stimulate HSC activation, while rEBI3 reduced the activation of HSCs induced by Cs.ESP. Also, the protein expression of gp130 and downstream protein expressions of JAK1, p-JAK1, STAT3 and p-STAT3 in HSCs were increased after rEBI3 incubation. Finally, intravenously injected rEBI3 inhibited hepatic epithelial-mesenchymal transition in C. sinensis-infected mice by inhibiting HSC activation and reducing liver injury. CONCLUSION: This study confirms that rEBI3 can attenuate C. sinensis-induced liver fibrosis by inhibiting HSC activation and may be one of the potential treatments for liver fibrosis.

Recent Advances in Nanoplatform Construction Strategy for Alleviating Tumor Hypoxia.

Hypoxia is a typical feature of most solid tumors and has important effects on tumor cells' proliferation, invasion, and metastasis. This is the key factor that leads to poor efficacy of different kinds of therapy including chemotherapy, radiotherapy, photodynamic therapy, etc. In recent years, the construction of hypoxia-relieving functional nanoplatforms through nanotechnology has become a new strategy to reverse the current situation of tumor microenvironment hypoxia and improve the effectiveness of tumor treatment. Here, the main strategies and recent progress in constructing nanoplatforms are focused on to directly carry oxygen, generate oxygen in situ, inhibit mitochondrial respiration, and enhance blood perfusion to alleviate tumor hypoxia. The advantages and disadvantages of these nanoplatforms are compared. Meanwhile, nanoplatforms based on organic and inorganic substances are also summarized and classified. Through the comprehensive overview, it is hoped that the summary of these nanoplatforms for alleviating hypoxia could provide new enlightenment and prospects for the construction of nanomaterials in this field.

Analysis of the Influence of Outward Bound Training Based on Data Analysis in College Physical Training.

The competition for talents in the modern society is constantly intensifying. College students not only have good physical and psychological quality but also bear hardships and stand hard work and adapt to the fast-paced working environment in order to adapt to the development of the times. With the advent of the era of big data, advanced technology has been applied to physical exercise and development, providing opportunities and challenges for the development of sports. Therefore, this paper focuses on the impact of expanding training on college sports training through extensive surveys on college students' outward bound training. The results show that data are the key data of analysis, which can be used to analyze college students' physical functions and other indicators scientifically and effectively. Universities should develop appropriate outward bound training according to the characteristics of the students themselves. The project helps to improve the sports performance and psychological and physical quality of college students. We hope to provide theoretical reference for experts and scholars who study the development of college sports.

The protective effects of 1,3-butanediol acetoacetate diester on decompression sickness in rats.

Inert gas bubbles are widely accepted as the causative factor of decompression sickness (DCS), resulting in gas embolism and systemic inflammatory responses. The anticonvulsive ketone ester 1,3-butanediol acetoacetate diester (BD-AcAc2) was reported to have the characteristics of increasing blood oxygen partial pressure (ppO2) and anti-inflammation and was thought to have the potential to reduce bubble formation and alleviate the pathological process of DCS. This study aims to investigate the potential protection of BD-AcAc2 against DCS in a rat model. A single dose of BD-AcAc2 was administered orally to adult male rats (5 g/kg body wt), followed by pharmacokinetic analysis or simulated air dives. After decompression, signs of DCS were monitored, and blood was sampled for biochemical measurements. Blood ketosis peaked at 2 h and lasted for more than 4 h. The incidence of DCS was decreased and postponed significantly in rats treated with BD-AcAc2 compared with those treated with saline (P < 0.05). Although BD-AcAc2 failed to reduce bubble load (P > 0.05), it showed an obvious decreasing trend. BD-AcAc2 significantly increased blood ppO2 and ameliorated oxidative and inflammatory responses, represented by increased plasma malondialdehyde (MDA), IL-1, IL-6, and TNF-α and decreased glutathione thiol (P < 0.05) levels, whereas blood pH remained unchanged (P > 0.05). These results suggest that BD-AcAc2 exerted beneficial effects on DCS rats mainly related to increasing ppO2 and anti-inflammatory and antioxidant properties. Together with its capacity for delaying central nervous system (CNS) oxygen toxicity seizures, BD-AcAc2 might be an ideal drug candidate for DCS prevention and treatment.NEW & NOTEWORTHY This is the first study exploring the effects of BD-AcAc2 on DCS prevention, and it was proven to be an efficient and simple method. The role of BD-AcAc2 in increasing ppO2, anti-inflammatory and antioxidant properties was thought to be the critical mechanism in DCS prevention.

MEK1/2 Inhibition Synergistically Enhances the Preventive Effects of Normobaric Oxygen on Spinal Cord Injury in Decompression Sickness Rats.

A previous study from our team found that hyperbaric oxygen (HBO) pretreatment attenuated decompression sickness (DCS) spinal cord injury by upregulating heat shock protein 32 (HSP32) via the ROS/p38 MAPK pathway. Meanwhile, a MEK1/2-negative regulatory pathway was also activated to inhibit HSP32 overexpression. The purpose of this study was to determine if normobaric oxygen (NBO) might effectively induce HSP32 while concurrently inhibiting MEK1/2 and to observe any protective effects on spinal cord injury in DCS rats. The expression of HSP32 in spinal cord tissue was measured at 6, 12, 18, and 24 h following NBO and MEK1/2 inhibitor U0126 pretreatment. The peak time of HSP32 was observed at 12 h after simulated air diving. Subsequently, signs of DCS, hindlimb motor function, and spinal cord and serum injury biomarkers were recorded. NBO-U0126 pretreatment significantly decreased the incidence of DCS, improved motor function, and attenuated oxidative stress, inflammatory response, and apoptosis in both the spinal cord and serum. These results suggest that pretreatment with NBO and U0126 combined can effectively alleviate DCS spinal cord injury in rats by upregulating HSP32. This may lead to a more convenient approach for DCS injury control, using non-pressurized NBO instead of HBO.

Effect of Transcriptional Regulatory Factor FoxO3a on Central Nervous System Oxygen Toxicity.

Central nervous system (CNS) oxygen toxicity (CNS-OT) is a toxic reaction that appears after the inhalation of gas at an excessive oxygen partial pressure during underwater operation or hyperbaric oxygen (HBO) treatment. The mechanism of CNS-OT has not been clearly characterized. Though it has been attributed to the excessive oxidative stress induced by HBO, evidences against this hypothesis have been reported. Here we find that Forkhead box protein O3 (FoxO3a) is important for CNS-OT protection. FoxO3a knock-out (KO) mice had a shorter latency to develop convulsions and greater number of seizures within a certain period of time. The acute lung injury (ALI) induced by CNS-OT was also more severe in FoxO3a KO mice. Further analysis reveals a significant decrease in the activity of catalase (CAT), an antioxidant enzyme and a significant increase in the content of malondialdehyde (MDA), an oxidative product, in brain tissues of FoxO3a KO mice. Short-time HBO exposure could increase FoxO3a expression level and trigger its nuclear translocation. The level of nuclear localized FoxO3a peaked at 8 h after exposure. Our results demonstrate that the activity of FoxO3a is highly sensitive to HBO exposure and FoxO3a plays important roles in protecting CNS-OT. Further mechanic analysis reveals that FoxO3a protects CNS-OT via activating antioxidative signaling pathway.

Biphasic effects of autophagy on decompression bubble-induced endothelial injury.

Endothelial dysfunction induced by bubbles plays an important role in decompression sickness (DCS), but the mechanism of which has not been clear. The present study was to investigate the role of autophagy in bubble-induced endothelial injury. Human umbilical vein endothelial cells (HUVECs) were treated with bubbles, autophagy markers and endothelial injury indices were determined, and relationship strengths were quantified. Effects of autophagy inhibitor 3-methyladenine (3-MA) were observed. Bubble contact for 1, 5, 10, 20 or 30 minutes induced significant autophagy with increases in LC3-II/I ratio and Beclin-1, and a decrease in P62, which correlated with bubble contact duration. Apoptosis rate, cytochrome C and cleaved caspase-3 increased, and cell viability decreased following bubble contact for 10, 20 or 30 minutes, but not for 1 or 5 minutes. Injuries in HUVECs were correlated with LC3-II/I ratio and partially reversed by 3-MA in 10, 20 or 30 minutes contact, but worsened in 1 or 5 minutes. Bubble pre-conditioning for 1 minutes resulted in increased cell viability and decreased apoptosis rate compared with no pre-conditioning, and 30-minutes pre-conditioning induced opposing changes, all of which were inhibited by 3-MA. In conclusion, autophagy was involved and played a biphasic role in bubble-induced endothelial injury.

A Novel Approach to Estimate ROS Origination by Hyperbaric Oxygen Exposure, Targeted Probes and Specific Inhibitors.

BACKGROUND/AIMS: Reactive oxygen species (ROS) are considered fundamental in various physiological/pathophysiological processes and prevention/treatment measures such as hyperbaric oxygen (HBO) therapy. In this study, the origination of ROS in human umbilical vein endothelial cells was investigated under basal and HBO conditions. METHODS: Whole cell or mitochondria-targeted fluorescent probes were applied to mark superoxide anion (O2-), and the ROS produced from mitochondrial respiratory chain (MRC), NADPH oxidase (NOX) and xanthine oxidase (XO) were identified by flow cytometry, confocal imaging and microplate fluorometry with or without specific inhibitors. An algorithm was established to calculate ROS proportion of each source. RESULTS: HBO increased ROS to about 2.14-2.44 fold in mitochondria and 1.32-1.42 fold in whole cell. Then ROS levels were significantly decreased by MRC inhibition about 30% and 16%, respectively. NOX or XO inhibition did not affect HBO-induced ROS generation. Based on these data, it could be further estimated that mitochondrial ROS accounted for 32%-39% of basal whole-cell ROS including 3% from MRC complex II, and NOX accounted for at least 24%-29%. Following HBO treatment, almost all increased ROS originated from mitochondria, and MRC complex II contributed at least 45%-60%. CONCLUSION: This study provided a simple but effective method to estimate the origination of intracellular ROS and found that MRC were the main source of HBO-induced ROS generation.

HSP70 protects rats and hippocampal neurons from central nervous system oxygen toxicity by suppression of NO production and NF-κB activation.

During diving, central nervous system oxygen toxicity may cause drowning or barotrauma, which has dramatically limited the working benefits of hyperbaric oxygen in underwater operations and clinical applications. The aim of this study is to understand the effects and the underlying mechanism of heat shock protein 70 on central nervous system oxygen toxicity and its mechanisms in vivo and in vitro. Rats were given geranylgeranylacetone (800 mg/kg) orally to induce hippocampal expression of heat shock protein 70 and then treated with hyperbaric oxygen. The time course of hippocampal heat shock protein 70 expression after geranylgeranylacetone administration was measured. Seizure latency and first electrical discharge were recorded to evaluate the effects of HSP70 on central nervous system oxygen toxicity. Effects of inhibitors of nitric oxide synthase and nuclear factor-κB on the seizure latencies and changes in nitric oxide, nitric oxide synthase, and nuclear factor-κB levels in the hippocampus tissues were examined. In cell experiments, hippocampal neurons were transfected with a virus vector carrying the heat shock protein 70 gene (H3445) before hyperbaric oxygen treatment. Cell viability, heat shock protein 70 expression, nitric oxide, nitric oxide synthase, and NF-κB levels in neurons were measured. The results showed that heat shock protein 70 expression significantly increased and peaked at 48 h after geranylgeranylacetone was given. Geranylgeranylacetone prolonged the first electrical discharge and seizure latencies, which was reversed by neuronal nitric oxide synthase, inducible nitric oxide synthase and NF-κB inhibitors. Nitric oxide, nitric oxide synthase, and inducible nitric oxide synthase levels in the hippocampus were significantly increased after hyperbaric oxygen exposure, but reversed by geranylgeranylacetone, while heat shock protein 70 inhibitor quercetin could inhibit this effect of geranylgeranylacetone. In the in vitro study, heat shock protein 70-overexpression decreased the nitric oxide, nitric oxide synthase, and inducible nitric oxide synthase levels as well as the cytoplasm/nucleus ratio of nuclear factor-κB and protected neurons from hyperbaric oxygen-induced cell injury. In conclusion, overexpression of heat shock protein 70 in hippocampal neurons may protect rats from central nervous system oxygen toxicity by suppression of neuronal nitric oxide synthase and inducible nitric oxide synthase-mediated nitric oxide production and translocation of nuclear factor-κB to nucleus. Impact statement Because the pathogenesis of central nervous system oxygen toxicity (CNS-OT) remains unclear, there are few interventions available. To develop an efficient strategy against CNS-OT, it is necessary to understand its pathogenesis and in particular, the relevant key factors involved. This study examined the protective effects of heat shock protein 70 (HSP70) on CNS-OT via in vivo and in vitro experiments. Our results indicated that overexpression of HSP70 in hippocampal neurons may protect rats from CNS-OT by suppression of nNOS and iNOS-mediated NO production and the activation of NF-κB. These findings contribute to clarification of the role of HSP70 in CNS-OT and provide us a potential novel target to prevent CNS-OT. Clarification of the involvement of NO, NOS and NF-κB provides new insights into the mechanism of CNS-OT and may help us to develop new approach against it by interfering these molecules.

Bubble-Induced Endothelial Microparticles Promote Endothelial Dysfunction.

Decompression sickness is a systemic pathophysiological process caused by bubbles and endothelial microparticles (EMPs) are established markers reflecting competency of endothelial function and vascular biology. Here, we investigated the effects of bubble-induced EMPs on endothelial cells in vitro and vivo. Rat pulmonary microvascular endothelial cells (PMVECs) were isolated and stimulated by bubbles and bubble-induced EMPs were collected and incubated with normal PMVECs in vitro. Cell viability and apoptosis were detected using Cell Counting Kit-8 assay and Annexin V FITC/PI double staining, respectively. Cell permeability and pro-inflammatory cytokines were determined by electric cell substrate impedance sensing and enzyme-linked immunosorbent assay, respectively. Intracellular nitric oxide and reactive oxygen species production were analyzed microscopically. In vivo study, bubble-induced EMPs were intravenously injected to the rats and soluble thrombomodulin, intercellular adhesion molecule 1, and vascullar adhesion molecule 1 were involved in evaluating endothelial dysfunction. In our study, bubble stimulus resulted in a significant increase of EMPs release by 3 fold. Bubble-induced EMPs significantly decreased cell viability and increased cell apoptosis. Moreover, bubble-induced EMPs induced abnormal increase of cell permeability and over-expression of pro-inflammatory cytokines. Intracellular ROS production increased while NO production decreased. These negative effects caused by bubble-induced EMPs were remarkably suppressed when EMPs pretreated with surfactant FSN-100. Finally, intravenous injection of bubble-induced EMPs caused elevations of soluble thrombomodulin and pro-inflammatory cytokines in the circulation. Altogether, our results demonstrated that bubble-induced EMPs can mediate endothelial dysfunction in vitro and vivo, which can be attenuated by EMPs abatement strategy. These data expanded our horizon of the detrimental effects of bubble-induced EMPs, which may be of great concern in DCS.

Signaling pathways involved in HSP32 induction by hyperbaric oxygen in rat spinal neurons.

Spinal cord injury (SCI) is a debilitating disease, effective prevention measures are in desperate need. Our previous work found that hyperbaric oxygen (HBO) preconditioning significantly protected rats from SCI after stimulated diving, and in vitro study further testified that HBO protected primary cultured rat spinal neurons from oxidative insult and oxygen glucose deprivation injury via heat shock protein (HSP) 32 induction. In this study, underlying molecular mechanisms were further investigated. The results showed that a single exposure to HBO significantly increased intracellular levels of reactive oxygen species (ROS) and nitric oxide (NO) and activated MEK1/2, ERK1/2, p38 MAPK, CREB, Bach1 and Nrf2. The induction of HSP32 by HBO was significantly reversed by pretreatment neurons with ROS scavenger N-Acetyl-L-cysteine, p38 MAPK inhibitor or Nrf2 gene knockdown, enhanced by MEK1/2 inhibitors or gene knockdown but not by ERK1/2 inhibitor. CREB knockdown did not change the expression of HSP32 induced by HBO. N-Acetyl-L-cysteine significantly inhibited the activation of MEK1/2, ERK1/2, p38 MAPK, and Nrf2. Activation of Nrf2 was significantly inhibited by p38 MAPK inhibitor and the nuclear export of Bach1 was significantly enhanced by MEK1/2 inhibitor. The results demonstrated that HBO induces HSP32 expression through a ROS/p38 MAPK/Nrf2 pathway and the MEK1/2/Bach1 pathway contributes to negative regulation in the process. More importantly, as we know, this is the first study to delineate that ERK1/2 is not the only physiological substrates of MEK1/2.

Effects of rapid decompression on HUVECs in vitro.

OBJECTIVE: To explore the possible effects of rapid decompression on the activity and function of vascular endothelial cells in vitro. METHODS: Human umbilical vein endothelial cell (HUVEC) cultures were exposed at 7 atmospheres absolute (atm abs) air for two hours before decompression. Two decompression profiles were used at the rate of 30 atm abs min-1 (rapid decompression) or 1 atm abs min-1 (normal decompression). Three hours after decompression, cell activity was detected by cell counting kit-8 (CCK-8) assay and lactate dehydrogenase (LDH) activity assay; cell permeability was measured by electrical resistance determinations. Twelve hours after decompression, cell apoptosis was detected by flow cytometry with Annexin V FITC/PI double staining. RESULTS: There was no significant statistical difference between rapid and normal decompression groups in all the determined parameters (P=0.59, 0.87, 0.86 and 0.81, respectively). CONCLUSIONS: HUVECs endure rapid decompression well from 7 atm abs at the rate of 30 atm abs min-1, or the current determinations are not sensitive enough to reveal the possible injuries. Further research with more sensitive indexes is warranted to reveal the possible effects and mechanisms.

Nrf2 activation in astrocytes contributes to spinal cord ischemic tolerance induced by hyperbaric oxygen preconditioning.

In this study, we investigated whether nuclear factor erythroid 2-related factor 2 (Nrf2) activation in astrocytes contributes to the neuroprotection induced by a single hyperbaric oxygen preconditioning (HBO-PC) against spinal cord ischemia/reperfusion (SCIR) injury. In vivo: At 24 h after a single HBO-PC at 2.5 atmospheres absolute for 90 min, the male ICR mice underwent SCIR injury by aortic cross-clamping surgery and observed for 48 h. HBO-PC significantly improved hindlimb motor function, reduced secondary spinal cord edema, ameliorated the reactivity of spinal motor-evoked potentials, and slowed down the process of apoptosis to exert neuroprotective effects against SCIR injury. At 12 h or 24 h after HBO-PC without aortic cross-clamping surgery, Western blot, enzyme-linked immunosorbent assay, realtime-polymerase chain reaction and double-immunofluorescence staining were used to detect the Nrf2 activity of spinal cord tissue, such as mRNA level, protein content, DNA binding activity, and the expression of downstream gene, such as glutamate-cysteine ligase, γ-glutamyltransferase, multidrug resistance protein 1, which are key proteins for intracellular glutathione synthesis and transit. The Nrf2 activity and downstream genes expression were all enhanced in normal spinal cord with HBO-PC. Glutathione content of spinal cord tissue with HBO-PC significantly increased at all time points after SCIR injury. Moreover, Nrf2 overexpression mainly occurs in astrocytes. In vitro: At 24 h after HBO-PC, the primary spinal astrocyte-neuron co-cultures from ICR mouse pups were subjected to oxygen-glucose deprivation (OGD) for 90 min to simulate the ischemia-reperfusion injury. HBO-PC significantly increased the survival rate of neurons and the glutathione content in culture medium, which was mainly released from asctrocytes. Moreover, the Nrf2 activity and downstream genes expression induced by HBO-PC were mainly enhanced in astrocytes, but not in neurons. In conclusion, our findings demonstrated that spinal cord ischemic tolerance induced by HBO-PC may be mainly related to Nrf2 activation in astrocytes.

Hyperbaric oxygen preconditioning induces tolerance against oxidative injury and oxygen-glucose deprivation by up-regulating heat shock protein 32 in rat spinal neurons.

OBJECTIVE: Hyperbaric oxygen (HBO) preconditioning (HBO-PC) has been testified to have protective effects on spinal cord injury (SCI). However, the mechanisms remain enigmatic. The present study aimed to explore the effects of HBO-PC on primary rat spinal neurons against oxidative injury and oxygen-glucose deprivation (OGD) and the relationship with heat shock proteins (HSPs). METHODS: Primary rat spinal neurons after 7 days of culture were used in this study. HSPs were detected in rat spinal neurons following a single exposure to HBO at different time points by Western blot. Using lactate dehydrogenase release assay and cell counting kit-8 assay, the injuries induced by hydrogen peroxide (H2O2) insult or OGD were determined and compared among neurons treated with HBO-PC with or without HSP inhibitors. RESULTS: The results of Western blot showed that HSP27, HSP70 and HSP90 have a slight but not significant increase in primary neurons following HBO exposure. However, HSP32 expression significantly increased and reached highest at 12 h following HBO exposure. HBO-PC significantly increased the cell viability and decreased the medium lactate dehydrogenase content in cultures treated with H2O2 or OGD. Pretreatment with zinc protoporphyrin IX, a specific inhibitor of HSP32, significantly blocked the protective effects of HBO-PC. CONCLUSIONS: These results suggest that HBO-PC could protect rat spinal neurons in vitro against oxidative injury and OGD mostly by up-regulating of HSP32 expression.

Protective effect of hydrogen sulfide on hyperbaric hyperoxia-induced lung injury in a rat model.

Hyperbaric oxygen therapy is one of the most widely used clinical interventions to counteract insufficient pulmonary oxygen delivery in patients with severe lung injury. However, prolonged exposure to hyperoxia leads to inflammation and acute lung injury. This study aimed to investigate the protective effect of hydrogen sulfide on hyperbaric hyperoxia-induced lung injury. Rats were intraperitoneally treated with sodium hydrosulphide (NaHS) at 28 µmol/kg immediately before hyperoxia exposure and then exposed to pure oxygen at 2.5 atmospheres absolute (atm abs) with continuous ventilation for six hours, Immediately after hyperoxia exposure, rats were sacrificed via anesthesia. The bronchoalveolar lavage fluid (BALF) was harvested for the detection of protein concentration and IL-1 content, and the lungs were collected for HE staining, TUNEL staining and detection of wet/dry weight ratio. Our results showed hyperbaric hyperoixa exposure could significantly damage the lung (HE staining), increase the protein and IL-13 in the BALF, elevate the wet/dry Weight ratio and raise the TUNEL positive cells. However, pre-treatment with hydrogen sulfide improved the lung morphology, reduced the TUNEL positive cells and attenuated the lung inflammation (reduction in IL-13 of BALF and HE staining). Taken together, our findings indicate that hydrogen sulfide pretreatment may exert protective effects on hyperbaric hyperoxia-induced lung injury.

Decompression illness: clinical aspects of 5278 consecutive cases treated in a single hyperbaric unit.

BACKGROUND: Decompression illness (DCI) is a major concern in pressure-related activities. Due to its specific prerequisite conditions, DCI is rare in comparison with other illnesses and most physicians are inexperienced in treatment. In a fishery area in northern China, during the past decade, tens of thousands of divers engaged in seafood harvesting and thousands suffered from DCI. We established a hyperbaric facility there and treated the majority of the cases. METHODS AND RESULTS: A total of 5,278 DCI cases were admitted in our facility from February 2000 through December 2010 and treated using our recompression schedules. Cutaneous abnormalities, joint and muscular pain and neurological manifestations were three most common symptoms. The initial symptom occurred within 6 h after surfacing in 98.9% of cases, with an overall median latency of 62 min. The shorter the latent time, the more serious the symptoms would be (P<0.0001). Nine cases died before recompression and 5,269 were treated using four recompression schedules, with an overall effectiveness rate of 99.3%. The full recovery rate decreased with the increase of the delay from the onset of symptoms to the treatment (P<0.0001). CONCLUSIONS: DCI presents specific occurrence rules. Recompression should be administered as soon as possible and should never be abandoned irrespective of the delay. The recompression schedules used were effective and flexible for variety conditions of DCI.