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OBJECTIVE To study the protective effects o f valproic acid on cardiac and cerebral injury in rats subjected to severe scalding combined with seawater immersion injury with delayed fluid replacement. METHODS The rats were divided into scalding+delayed fluid replacement group （group S ），scalding+seawater immersion+delayed fluid replacement group （group SS ）， scalding+seawater immersion+valproic acid+delayed fluid replacement group （group SSV ）according to random number table ，with 60 rats in each group. All groups were subjected to 35％total body surface area third-degree full-thickness scalding with boiled water. Group SS and group SSV were immersed in artificial ；seawater（30 min）immediately after scalding ，and group SSV was subcutaneously injected with valproic acid 300 mg/kg immediately after out of water. Sodium lactate Ringer ’s 0314-2279277。E-mail：125467374@qq.com injection was injected intravenously within 30 minutes according to 1/2 Parkland formula at 2 h after scalding in each group for delayed fluid replacement. The death time of rats was recorded ，and the average survival time and 24 h survival rate of rats in each group were calculat ed. Mean arterial pressure （MAP），heart rate （HR），respiration rate （RR），rectal temperature （RT），arterial blood pH ，arterial partial pressure of oxygen （PaO2），arterial blood partial pressure of carbon dioxide （PaCO2），HCO3－，creatine kinase MB isoenzyme （CK-MB）and neuron specific enolase （NSE）were detected before scalding ，at 0，2，5 h after scalding. The pathological changes of cardiac and cerebral tissue were observed. RESULTS The 24 h survival rate of group SS （55％）was significantly lower than that of group S （90％）， while that of group SSV （75％）was increased significantly ，compared with group SS （P＜0.05）. Compared with group S ，the levels of MAP ，RT，HR，pH，PaO2 and HCO 3－ in group SS were significantly lowered ，while the levels of CK-MB and NSE were increased significantly at 0，2，5 h after scalding ；the levels of PaCO 2 were increased significantly at 2，5 h after scalding ， while the levels of RR were decreased significantly at 0，2 h after scalding （P＜0.05）. Compared with group SS ，the levels of MAP，RT，HR，pH，PaO2 and HCO 3－ in group SSV were significantly increased ，while the levels of PaCO 2，CK-MB and NSE were decreased significantly at 2，5 h after scalding ；the level of RR was increased significantly at 2 h after scalding （P＜0.05）. At 2，5 h after scalding ，cardiac and cerebral injury of rats in group SS were aggravated significantly than that in group S ；cardiac and cerebral injury of rats in group SSV were relieved significantly than that in group SS. CONCLUSIONS After severe scalding combined seawater immersion injury ，hypodermic injection of sodium valproate could protect cardiac and cerebral function of rats ， improve vital signs and blood gas index ，prolong survival time and improve survival rate in rats.
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Objective To observe the success rate and rewarming curve of different water bath rewarming in rats with severe seawater immersed hypothermia. Methods A total of 490 male SD rats were intraperitoneally implanted with temperature recorder before experiment, were randomly divided into immersion group (n=450) and control group (n=40). In immersion group 100 rats were immersed in (15.0±0.2) °C seawater for 2 h, 150 rats for 5 h, and 200 rats for 10 h. The survival rats of each group were randomly divided into five subgroups and given different rewarming treatments: passive rewarming (passive rewarming subgroup), 37 °C hot water bath rewarming for 0.5 h (37 °C active rewarming 0.5 h subgroup), 37 °C hot water bath rewarming for 1 h (37 °C active rewarming 1 h subgroup), 42 °C hot water bath rewarming for 0.5 h (42 °C active rewarming 0.5 h subgroup), 42 °C hot water bath rewarming for 1 h (42 °C active rewarming 1 h subgroup). The rats in the control group were without seawater immersion, and were randomized into four subgroups as above. The success rate of rewarming was calculated in each group. The serum levels of creatine kinase isoenzyme (CK-MB), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) were determined in the survival rats after rewarming for 20 h. Dynamic intraperitoneal temperature was recorded at the end of the experiment, and then the passive rewarming velocity, delay afterdrop effect of hot water bath rewarming were calculated. Results With the prolongation of immersing time, the survival rate of rats was significantly decreased in the immersion group (P<0.05). The rewarming success rates were significantly decreased in both the passive and active rewarming groups (both P<0.05). The rewarming success rate in the 37 °C active rewarming 1 h subgroup was greater than or equal to other active rewarming subgroups and the passive rewarming subgroup. All rats in the control group survived after hot water bath. Compared with the control group, the serum levels of CK-MB, ALT and LDH were significantly increased in the surviving rats of the active rewarming subgroups with the prolongation of immersion time (P<0.05). At the same immersing time, the levels of CK-MB, ALT and LDH were significantly lower in the 37 °C active rewarming 1 h subgroup than those in the other active rewarming subgroups (P<0.05 for some results), and were lower than those in the passive rewarming subgroup (P<0.05 for some results). Rewarming curve showed that the rewarming velocity of the passive rewarming subgroup significantly decreased with the prolongation of immersing time (P<0.05), and the rewarming velocity of the dead rats was significantly lower than that of the surviving rats (P<0.05). Delayed afterdrop effect was found in abdominal temperature of hot water rewarming rats, and the greater the effect was, the higher the mortality rate was. The delayed afterdrop effect of 37 °C hot water bath was not obvious in the control group, but it was significantly obvious in 42 °C hot water bath subgroups (P<0.05). Conclusion The success rate of proper hot water bath rewarming is greater than that of passive rewarming in the treatment of severe seawater immersed hypothermia. Hot water bath can be used as a rewarming option in emergency situations, while improper rewarming conditions can decrease the treatment success rate, which may be related to the delayed afterdrop effect.
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It is hard to deal with traumatic brain injury combined with seawater insult and its high motility.Findings have been made in recent preclinical and clinical researches into the traumatic brain injury combined with seawater insult,but further studies are needed because the mechanisms associated with the injury are not completely figured out.This paper summarizes the current basic and clinical researches into the injury,intending to find clues to improve the practical treatment and to guide oncoming studies of the injury.
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Objective To study the effect of applying a new intravenous resuscitation solution to electrolyte imbalance in miniature pigs after seawater immersion injury.Methods A total of 20 Guizhou Ⅲ type miniature pigs aged 4 months were randomly divided to A and B groups,10 in each.The seawater immersion injury model was used to soak sea water for 3 hours.The changes of electrolytes in miniature pigs before and after soaking wererecorded.A group with intravenous infusion of 0.9％ sodium chloride solution,and B group with new type ofrecovery liquid intravenous rehydration.Electrolyte changes after infusion were recorded and analyzed.Data ofnormal distribution measurement data were expressed as ((x) ± s).The data of electrolyte before and after immersionwere analyzed by paired t test.After soaking,the relative data of electrolyte after sub-group rehydration wereanalyzed by independent sample t test.Results After seawater immersion,pH value were dropped from 7.39 ±0.06and 7.39 ±0.04 to 7.32 ±0.05 and 7.33 ±0.05,serum K + concentration elevated from (3.93 ±0.38) mmol/Land (3.93±0.42) mmol/L to (4.35 ±0.33) mmol/L and (4.37 ±0.14) mmol/L.Clconcentration increased from (93.38 ± 4.29) mmol/L and (92.88 ± 3.79) mmol/L to (102.80 ± 4.29) mmol/Land (103.50±2.46) mmol/L.Na+ concentration in serum were dropped from (140.64 ± 4.99) mmol/L and(140.69 ±4.72) mmol/L to (136.80 ±4.32) mmol/L and (136.90 ±3.03) mmol/L.After normal saline andnew type of recovery liquid rehydration respectively,group B with new recovery liquid,pH increased from 7.33 ±0.05 to 7.38 ±0.04 (P ＜0.05),serum concentration of K+ and Cl-concentration were dropped from (4.37 ±0.14) mmol/L and (103.50 ±2.46) mmol/L to (3.87 ±0.25) mmol/L and (94.15 ±4.23) mmol/L (P =0.005,P =0.007).The concentration of serum Na + back up from (136.90 ± 3.03) mmol/L to (139.30 ±3.06) mmol/L (P =0.038).A group of saline infusion after the various indicators did not change significantly.Conclusion The new intravenous resuscitation solution of miniature pigs electrolyte imbalance correction effect issignificant,that the resuscitation solution has some clinical value for seawater immersion iniurv.
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Objective@#To study the effects of seawater immersion on the inflammatory response and oxygen free radical injury of rats with superficial-thickness scald at early stage.@*Methods@#Seventy Wistar rats were divided into healthy control group (HC, n=7), pure scald group (PS, n=21), scald+ fresh water immersion group (SF, n=21), and scald+ seawater immersion group (SS, n=21) according to the random number table. Rats in group HC did not receive any treatment, while 5% total body surface area superficial partial-thickness scald was made on the back of rats in the latter three groups. Rats in group PS lived freely immediately post burn, while wounds on the back of rats in groups SF and SS were immersed into fresh water and seawater, respectively. Serum and full-thickness skin tissue in the center of wounds on the back of 7 rats in groups PS, SF, and SS at post immersion (injury) hour (PIH) 2, 4, and 6 were collected, respectively, while serum and full-thickness skin tissue at the same position of the 7 rats in group HC were collected at PIH 6 of rats in other groups. Morphology of skin tissue was observed with HE staining; tumor necrosis factor-alpha (TNF-α) content in serum and skin tissue was determined by enzyme-linked immunosorbent assay; superoxide dismutase (SOD) content in serum and skin tissue was determined by hydroxylamine method; malondialdehyde content in serum and skin tissue was determined by thiobarbituric acid method. Data were processed with analysis of variance of factorial design, one-way analysis of variance, Welch test, LSD test, and Tamhane test.@*Results@#(1) Epidermal cells of skin tissue of rats in group HC arranged in order and continuously, and the dermis tissue and accessory structures were clear and complete. The skin layer and epidermis of wounds of rats in group PS had no significant change, but the edema of epidermis and dermis and infiltration of inflammatory cells enhanced over time at PIH 2, 4, and 6. The horny layer of epidermis of wounds of rats in group SF reduced, and the edema of epidermis and dermis and infiltration of inflammatory cells enhanced over time at PIH 2, 4, and 6; some epidermal cells disintegrated at PIH 6. The horny layer of epidermis of wounds of rats in group SS significantly reduced, along with the increase in disintegration of epidermal cells, the significant enhancement of edema of epidermis and dermis, and infiltration of a large number of inflammatory cells over time at PIH 2, 4, and 6. (2) Compared with (247±27) pg/mL in group HC, the serum content of TNF-α of rats in group PS significantly increased at PIH 2 and 4 [respectively (675±122) and (367±54) pg/mL, P<0.05 or P<0.01] but significantly decreased at PIH 6 [(147±27) pg/mL, P<0.01]; the serum content of TNF-α of rats in group SF significantly decreased at PIH 6 [(90±24) pg/mL, P<0.01]; the serum content of TNF-α of rats in group SS significantly increased at PIH 2, 4, and 6 [respectively (1 646±58), (2 086±114), and (2 951±58) pg/mL, with P values below 0.01]. Compared with (364±123) U/mL in group HC, the serum content of SOD of rats in group PS significantly increased at PIH 2 and 4 [respectively (489±13) and (447±14) U/mL, with P values below 0.05]; the serum content of SOD of rats in group SF significantly decreased at PIH 6 [(282±13) U/mL, P<0.05]; the serum content of SOD of rats in group SS significantly increased at PIH 2 [(461±23) U/mL, P<0.05] but significantly decreased at PIH 4 and 6 [respectively (226±8) and (205±10) U/mL, with P values below 0.01]. Compared with that in group HC, the serum content of malondialdehyde of rats in groups PS, SF, and SS significantly increased at PIH 2, 4, and 6 (with P values below 0.01). (3) Compared with that in group HC, the TNF-α content in wound tissue of rats in groups PS and SS significantly increased at PIH 2, 4, and 6 (P<0.05 or P<0.01), and the TNF-α content in wound tissue of rats in group SF significantly increased at PIH 2 and 4 (with P values below 0.01). Compared with that in group HC, the SOD content in wound tissue of rats in groups PS and SF significantly increased at PIH 2, 4, and 6 (P<0.05 or P<0.01), and the SOD content in wound tissue of rats in group SS significantly increased at PIH 2 and 4 (with P values below 0.01). Compared with that in group HC, the malondialdehyde content in wound tissue of rats in groups PS, SF, and SS significantly increased at PIH 2, 4, and 6 (with P values below 0.01).@*Conclusions@#Seawater immersion can enhance the inflammatory response and oxygen free radical injury of wounds and the whole body of rats with superficial partial-thickness scald at early stage.
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Objective To observe the protective effects of melatonin against spinal cord injury from seawater immersion in rabbits.Methods The 120 mature and health New Zealand White rabbits,weight range from 2.6 to 2.9kg,were randomly divided into four groups (30 each):control group,ethanol group,melatonin group (100mg/kg),methylPrednisolone group (30mg/kg).The rabbit model of spinal cord injury were built by modified Allen's method taking the 10th thoracic vertebra as a center,seawater immersion for 60 minutes,and then by grouping to give the appropriate treatment.After each group was given the corresponding treatment,six rabbits in each group were randomly selected at 1,6,12,24 and 48 hours five different time points.The neurological function scores of the rabbits were evaluated by Tarlov method,the spinal cord ofT9 to T.which were obtained from all the groups were used for further study,including immunohistochemical detection of apoptosis proteins:Bax,Bcl-2,neurofilament protein 200 (NF200) and in situ end labeling (TUNEL) method to detect spinal neuronal cell apoptosis.Results Within each observation time point,the Tarlov score was higher in melatonin group and methylprednisolone group compared with control group and ethanol group (P＜0.05),there was no significant difference between melatonin group and methylprednisolone group (P＞0.05).The expressions of Bcl-2 and NF200 were significantly higher in melatonin group and methylprednisolone group compared with control group and ethanol group,while Bax expression was significantly lower (P＜0.05).There were no significant difference between melatonin group and methylprednisolone group in the expression of three proteins (P＞0.05).The TUNEL-positive apoptotic cells were fewer in melatonin group and methylprednisolone group compared with control group and ethanol group (P＜0.05),and there was no significant difference between melatonin group and methylprednisolone group (P＞0.05).Conclusion Melatonin has protective effect against spinal cord injury from seawater immersion in rabbits,no difference in efficacy exists compare with methylprednisolone.
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Objective To observe the effects of seawater immersion at different temperatures on survival time and mortality and physiological state of non-anesthetized rats.Methods Totally 100 SD male rats(The abdominal cavity was implanted with a temperature sensor in advance)were randomly divided into five groups which were immersed in 20 ℃,17 ℃,15 ℃,13 ℃ and 10 ℃ seawater,respectively.Each group contains 20 rats.The changes of respiration,heart rate and muscle fibrillation within 2 hours were observed and the survival time and mortality of each group were counted in 24 hours.The decrease trend of intraperitoneal temperature in rats was analyzed retrospectively within 2 hours.Results Soaking for 10 minutes,the respiratory and heart rate of each group were significantly increased,but there was no significant difference among groups(P>0.05).The respiratory and heart rate decreased rapidly between 10 and 40 minutes,and the decline was slower relatively between 40 and 80 minutes.Soaking for 80 minutes,the respiration rate of rats among groups had significant difference(P0.05),hereafter the muscle fibrillation was maintained at a certain level.The mean survival time of 20 ℃ group,17 ℃ group,15 ℃ group,13 ℃ group and 10 ℃ group in 24 hours were(23.6±1.23)hours,(15.0±4.16)hours,(7.7±3.21)hours,(2.4±0.91)hours and (1.1±0.39)hours,respectively,and the survival curve of each group was statistically significant(P<0.05).The intraperitoneal temperature of rats showed a decline in the cliff,the lower the water temperature,the faster the descending.Soaking for 40 minutes,the difference of intraperitoneal temperature of each group was statistically significant(P<0.05).Conclusion The effects of seawater immersion at different temperatures on the physiological state and survival time and mortality of rats are significantly different.With the decrease of water temperature,the physiological state changes more obviously,the survival time is shorter and the mortality rate is higher.
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Objective To evaluate the effects of regional seawater immersion on the pain behavior and its secondary neuropathological change in the rats model of skin/muscle incision and retraction (SMIR). Methods Forty-eight male SD rats were randomly assigned into 3 groups (16 each): the model control group (only to set up SMIR model, Group MC), normal saline immersion group (to set up SMIR model and the incision immersed with normal saline, Group NS), seawater immersion group (to set up SMIR model and the incision immersed with seawater, Group SW). Mechanical paw withdrawal threshold (MWT) was measured 1d before and 1d, 3d, 5d, 7d, 14d, 21d and 28d after operation, respectively. At 3d and 28d after the operation, 8 rats were randomly selected from each group, ipsilateral saphenous nerves were taken from 4 rats for HE staining, and dorsal root ganglion of ipsilateral L3/L4 were taken from another 4 rats for ultrastructural observation by electron microscopy. Results Compared with the other two groups, MWT values in Group SW significantly reduced at every observation time and remained significantly lower than the basic level at 28d. There were no differences in MWT values between Group MC and Group NS, and the MWT values of the two groups at 28d were comparable with preoperative basic level. The HE staining of Group SW showed saphenous nerves were injured, while of Group MC and Group NS were normal. A large number of vacuolar mitochondrion and autophagosomes were observed in dorsal root ganglion of Group SW and few swelling mitochondrion was found in the other two groups. Conclusions Regional seawater immersion can aggravate the pain evoked by SMIR and may result in chronic pain. Peripheral nerve injury, ultrastructure changes of dorsal root ganglion neurons in rats caused by regional seawater immersion may be involved in the mechanism of the change of pain behavior.
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Objective To establish an animal model of open craniocerebral injury with seawater immersion and to study the characteristics of the injury. Methods A total of 100 healthy ma! SD rats were divided into 5 groups: control group, mild injury + seawater immersion group, moderate injury + seawater immersion group, severe injury + seawater immersion group and severe injury + normal saline immersion group. After SD rats had received a controlled cortical impact (CCI) injury, the injured brain tissue was soaked in seawater or normal saline to construct an animal model of open craniocerebral injury. We then observed the characteristics of the model, including the animal behavior, pathological changes, brain water content and the levll of blood brain barrier (BBB) opening. Results The animal model could well simulate the characteristics of the open craniocerebral injury with seawater immersion. With the increase of brain injury severity, the cerebral dysfunction, cerebral pathology, cerebral water content, and the damage of BBB became more serious. The pathological changes of brain tissue necrosis and bleeding in severe injury + seawater immersion group were more nota Me than those in the severe injury + normal saline immersion group. Compared with the severe injury + saline immersion group, the water content of brain tissue and the damage of BBB were significantly increased in the severe injury+ seawater immersion group after immersion for 24 h. Conclusion The rat model we established in this study can simulate the open craniocerebral injury with seawater immersion.
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Objective To investigate the nursing of replantation methods of sea-water soaked rotated avulsion amputated fingers.Methods There were 8 cases (16 fingers) with sea-water soaked rotated avulsion amputated fingers.5 cases were replanted by synchronic replantation method,the other 3 cases were replanted by traditional replantation method.We adopted complete debridement and high quality vascular anastomosis during the operation,and give hyperbaric oxygen therapy and anticoagulant treatment post-operation.Results There were 15 survival fingers in 16 replanted fingers.The survival rate was 93.75％.After follow-up for three months to two years,the total good rate was 87.5％.No wound infection and nonunion of fracture occurred.The outline of the fingers was satisfying and patients felt well.The twopoint discrimination was 3～6 mm after 3～24 months follow-up.Conclusions The injury of sea-water soaked rotated avulsion amputated fingers is complicated and the replantation operation is difficult.but if we can adopt individual measure according to the actual circumstance,it is possible that the sea-water soaked rotated avulsion amputated fingers can survive.
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Objective To investigate the effective treatments of combined injury with craniocerebral firearm wound in dogs immersed by seawater under maritime environment. Methods Models of combined injury with craniocerebral firearm wound, including craniocerebral gunshot wound,open chest injury, open abdominal injury, open trauma of extremities and burn injury, were established in 60 healthy adult mongrel dogs. Animal models after being wounded were immersed by the seawater for 30 min, and then, they were equally randomized into conventional treatment group and comprehensive treatment group; 30 dogs in the conventional treatment group were given routine treatment and the other 30 dogs in the comprehensive treatment group were given lukewarm glucose liquid, β-aescin, naloxone hydrochloride, levofloxacin and re-warming treatments besides the conventional treatment. Transcranial Doppler ultrasound, blood gas analysis, measurement of plasma osmotic pressure and intracranial pressure (ICP) monitoring were performed on the dogs of the 2 groups; and the treatment efficacy of the 2groups were compared. Results Low incidence rate of brain vasospasm was noted and TCD indicated that blood flow speed approached normal in the comprehensive treatment group 3 h after the treatment.The plasma osmotic pressure and the indicators of metabolic acidosis reached normal levels in the comprehensive treatment group 12 h after the treatment. The ICP significantly decreased in the comprehensive treatment group 24 h after the treatment. Survival rate in the comprehensive treatment group (70%) was significantly higher as compared with that in the conventional treatment group (53%)7 d after the treatment (P＜0.05). All the indexes in the comprehensive treatment group were better than those in the conventional treatment group (P＜0.05) Conclusion Early infusion of lukewarm hypotonic solution can significantly reduce the osmotic pressure, correct the electrolyte balance, help the re-warming and prolong the survival rate. Naloxone possesses protective effect on brain. The β-aescine sodium can diminish viscosity, slow down brain edema progress, obviously reduce ICP and improve brain tissue oxygen metabolism. In a word, comprehensive treatment in effective in treating combined injury with craniocerebral firearm wound.
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Objective: To establish a stress ulcer model by seawater immersion and restriction in rats, and to investigate the mechanism of preconditioning on stress ulcer and the effect of different stressing periods on the ulcer. Methods: A total of 60 male Wistar rats were equally divided into 6 groups, namely, the normal control group (Group A), direct stress group(Group B), precondition group I (Group C), precondition group II (Group S), precondition group III (Group E), and ranitidine group (Group F). Precondition peroids of C,D,E groups were 0.5 h/d, 1 h/d, and 1 h/d, respectively, for 5 days. Stress time in E group was 10 h,and in B,C,D,and F groups were 8 h. Radioimmunoassay was used to determine the sets levels of endothelin (ET) and 6-dk-dPGF1α in rats. Ulcer index was calculated by Guth method; the ulcer lesion tissues were collected for further pathological examination. Results: The sera ET levels in group C, D and F were lower than those in group B(P<0.01,P< 0.05,and P<0.01, respectively). The sera 6-dk-dPGF1α levels in group C, D and F were significantly higher than those in group B(P<0.01,P<0.05,and P<0.01, respectively). The ulcer indices in group C, D and F were significantly lower than those in group B (P<0.01,P<0.05,and P<0.01, respectively). The pathological results were improved in group C, D, and F compared with those in group B. Conclusion: Preconditioning can effectively reduce the rat stress ulcer,but long-time stressing may offset the protective effect of precondition.
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In order to monitor the influence of long time seawater immersion on human body,a multi-frequency electrical impedance measurement system was established.Based on this system,electrical impedance information of 10 soldiers was collected at different time during 6h of continuous seawater immersion.The results showed that as the immersion time lasting,the electrical impedance characteristic parameters R0?R∞ and ? decreased significantly.And the fc also decreased after 6h seawater immersion.Therefore,the electrical impedance technique can be used as a means to monitoring the degree of seawater immersion.
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Objective To study the influence and mechanism of seawater immersion on endothelial cell injury sustained by burn firearm combined injury to improve the early therapeutic efficacy. Methods The dogs with burn firearm combined injury were randomly divided into two groups: immersion group and control group. In immersion group, the dogs were immersed in seawater for 4 hours, then taken out from seawater. Blood samples were collected from central vein at 4 h, 7 h, 10 h, 20 h and 28 h following wound for the detection of changes of the circulating endothelial cells (CEC) and von Willebrand Factor (vWF). The same procedures except immersion were performed in the control group. Results The levels of CEC and vWF elevated at 4 h and 7 h following wound in control group( P
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Objective To observe the histological characteristics of the rabbit patellar ligaments repaired after blast injury and seawater immersion. Methods Explosive wounds were made at the knee joints of 36 New Zealand white rabbits with a 0.9 g detonator fastened on the anterolateral side of the joint. Then the wounds were immersed in seawater for 1 hour. After debridement and anti-inflammatory treatment, the broken patellar ligaments were sutured at the 4th day (n=19) and the 6th day (n=1) respectively. Histological examinations and electronic microscope observations of the injured and ruptured patellar ligaments were done respectively soon after blast injury, 1 hour after seawater immersion, 1 month, 2 months and 3 months after repair. Results The distortion and contracture of the ligament fibers were shown in the explosive injury group (n=14). The ligament fibers were broken and the fibroblasts were stacked in disorder in the rupture group (n=22). In the 2 groups, the ligament samples contained mainly collagen Ⅰ. The edema of tissue appeared after seawater immersion for 1 hour and the majority elements were collagen Ⅲ. 3 months after repair, the ligaments in the explosive injury group recovered almost to normal while in the rupture group the fiber arrangement was not compact and the fibroblasts were obviously fewer than those in the explosive injury group. Conclusions After explosive injury and seawater immersion, the rabbit patellar ligaments mainly excrete collagen Ⅲ. 3 months is enough for ligaments to repair the explosive injury. Even after treatment and 3 months’repair, there is still a distinct difference between the formerly ruptured ligaments and the normal tissue.
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Objective To evaluate the effect of various rewarming regimes on rectal temperature and hemodynamic parameters of dogs after open abdominal injury and seawater immersion. Method 30 healthy dogs were subjected to open abdominal injury and 2-hour seawater immersion. Then dogs were divided into three groups: group A (n=10) received no special warming treatment, in group B(n=10) electric blanket was used to warm up to 42℃, in group C (n=10) animals were warmed by 1/3 saline solution in 42℃ for 20 minutes and continuous perfusion of the abdominal cavity with 1/2 saline solution for 2 hours. The changes in body temperature, heart rate, MAP, CVP and CO were observed before and after rescue. Results The results of group A were not satisfactory. The rectal temperature, MAP, HR and CO were not recovered to normal after 6 hours of treatment. and the rectal temperature was 34.8℃ after 6 hours. The rectal temperature rose to 36.9℃ after being rewarmed with an electric blanket in group B. The result was better than that of group A. But there was tachycardia. The effects of rewarming from hypothermia in group C was satisfied. All hemodynamic parameters and rectal temperature recovered after 4 hours treatment. Conclusion Cold seawater immersion after open abdominal injury would result to hypothermia, and intra-corporeal rewarming should be the optional treatment.
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Objective A dog model of blast-burn combined injuries followed by immersion in seawater was reproduced in dog to study hemodynamic responses and their mechanism. Methods The dogs which were exposed to blast injuries produced by primer explosion and 10% second degree burn were randomly divided into seawater immersion group and blast-burn only group. The dogs in immersion group were immersed in seawater under anesthesia for 4 hours. The hemodynamics of the dogs was monitored, and blood samples were collected to assay malondialdehyde (MDA), and cultured for bacteria. After the above procedures were completed, the pathological changes in the dogs′ hearts and lungs were observed. The dogs in blast-burn group underwent the same protocol in immersion group except immersion. Results The body temperature (T), cardiac index (CI), mean arterial pressure (MAP), and heart rate (HR) in dogs in the immersion group were remarkably decreased, while the mean pulmonary artery pressure (MPAAP), systemic vascular resistance index (SVRI), and pulmonary vascular resistance index (PVRI) were markedly increased compared with those in blast-burn group. These obvious hemo dynamic disorders occurred during 3h to 6h after the dogs leaving seawater. Plasma MDA level was negatively correlated with CI. The interval between positive blood calture for intestinal bacteria and injury was shorter in immersion group than that of blast-burn group. The gross and histopathological changes in dogs′ hearts and lungs in immersion group injuries were more severe in degree than in blast-burn group. Conclusions Seawater immersion markedly aggravates the hemodynamic disorders in dogs having had blast-burn combined injury. The changes became obvious during 3h to 6h after leaving seawater. The aggravating effect might be related with declination of body temperature, inflammatory response and lipid peroxidation.
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Objective The aim of this study was to investigate the relationship of gastric mucosal lesions and the parietal oxyntic function in rats under stress as a result of seawater-immersion after open abdominal injury. Methods Thirty-two SD rats were subjected to open abdominal injury followed by seawater immersion. The animals were randomly divided into four groups: control, 1h, 2h, 3h stress for 1h, 2h, and 3h groups. The pH value of gastric juice and gastric mucosal ulcer index (UI) were measured. The gastric mucosal lesions were observed with light microscopy, and the ultrastructural changes in parietal cells were observed by transmission electron microscopy. Results There was a significantly negative relationship between UI and pH value (r=-0.70,P
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Objective To evaluate the effect of seawater immersion on hemodynamics and pathological changes in dogs with perforating injury of the intestine. Methods Thirty healthy adult dogs were subjected to perforating injury of the intestine. Ten injured dogs were immersed in artificial seawater after the injury. An equal number of injured dogs were immersed in normal saline solution. Control group dogs (n=10) were not subjected to salt water immersion. Hemodynamical and pathological changes were observed at different time intervals after injury. Results Obvious hemodynamic disorder and serious pathological changes were found after seawater immersion. Normal saline solution group and control group dogs did not show obvious disorders in hemodynamics and pathology. Conclusion Seawater immersion is one of the main factors leading to the disturbance in hemodynamic and pathological changes after perforating injury of the intestine.
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Objective To investigate the effects of different temperature seawater immersion on the hemodynamic of traumato-hemorrhagic shock rats. Methods 40 male traumato-hemorrhagic shock rats were utilized in this experiment. The hemodynamic parameters were determined in rats at preshock, shock, 10min, 30min, 1h, 3h, 5h after immersion in 15℃, 21℃ and 31℃ seawater respectively. Results The hemodynamic parameters of rats immersed in 21℃ seawater were markedly decreased compared with those of land control group. The hemodynamic parameters of rats immersed in 15℃ seawater rapidly decreased as compared with other groups. After 1 hour immersed in 15℃ seawater, the MAP, HR, ?dpdtmax of traumato-hemorrhagic shock rats were significantly decreased (P