Characteristics and mechanism of lower limb injury induced by landmine blast: A research in a rabbit model.

BACKGROUND: Limb injuries caused by landmine explosions are tricky to treat and difficult to protect. It is necessary to establish an animal model for studying lower limb injury and to investigate the characteristics and mechanisms of lower limb injury induced by landmine blasts. METHODS: Twenty-six mature white rabbits were randomly divided into sham group (n=10) and injury group (n=16). Landmine blast was simulated by electric detonators under the right lower limb in upright state by a special modified fixation frame. High-speed photography was used to observe the body movements. Vital signs, vascular injury (determining by digital subtraction angiography), pathological characteristics, and ATP concentration of the tibialis anterior muscle and triceps surae of shank were recorded for com-parison. RESULTS: Generally, middle and lower segment of the injured legs of the rabbits was seriously damaged. The limb stump presents a distribution of three areas, tissue free zone, contusion hematoma, and edema contusion. Sneak wound track, myofascial destruction, and periosteum stripping were typical characteristics of landmine blast injury. ATP concentration and pathological analysis showed that the tibialis anterior muscle was the most seriously injured, followed by the gastrocnemius and soleus. ATP concentration of affected muscle of both the contusion and commotio area declined remarkably over time, but the muscle in the avulsion area stayed at a low activity level with no change over the time. Small vascular injury in the contusion area was evident. The site of the sciatic nerve lesion was higher than the muscle. Injured site of sciatic nerve injury was higher than serious contusion muscle. High-speed photography demonstrated that the joints of the injured limb extremely flexed followed by a rapid stretch under the blast shock wave. CONCLUSION: The established experimental model presents typical effect of lower limbs wounded by the mine blast in war field. Landmine blast can cause typical damage on lower limbs including nerve lesion, knee injury, and microcirculation damage that is pro-gressive over time. The limb stump is divided into three zones based on gross pathology and micropathology, which can provide an important reference for clinical treatments and prognosis.

Efficacy of a Temporary Hemostatic Device in a Swine Model of Closed, Lethal Liver Injury.

INTRODUCTION: Solid abdominal organ hemorrhage remains one of the leading causes of death both on the battlefield of modern warfare and in the civilian setting. A novel, temporary hemostatic device combining CELOX and direct intra-abdominal physical compression was invented to control closed SAOH during transport to a medical treatment facility. MATERIALS AND METHODS: A swine model of closed, lethal liver injury was established to determine hemostasis. The animals were randomly divided into group A (extra-abdominal compression), group B (gauze packing), group C (intra-abdominal compression), group D (CELOX coverage), and group E (intra-abdominal compression and CELOX coverage) with six swines per group. Survival time (ST), blood loss (BL), vital signs, pathologic examination, and CT-scan were monitored to further observe the effectiveness of the device. RESULTS: Group E had an average 30-minute extension in ST (74.3 ± 15.4 minutes versus 44.0 ± 13.8 minutes, p = 0.026) with less BL (46.0 ± 13.0 versus 70.8 ± 8.2 g/kg, p = 0.018), and maintained mean arterial pressure≥70 mmHg and cardiac output ≥ 3.5 L/minute for a longer time. No significant differences were observed in ST and BL of groups B and E, and there were no marked differences in ST and BL of groups A, C, and D. No CELOX clots were noted in the spleen, pancreas, lungs, heart, kidneys, or the adjacent large vessels in groups D and E. Compared to group A, the CT-scan showed better hepatic hemorrhage control in group E. CONCLUSIONS: The device, which combined 20 g of CELOX particles and 20 pieces of CELOX (8 g) sponge tablets with 50-mmHg intra-abdominal compression for 10 minutes, prolonged the ST by an average of 30 minutes with less BL. It was not markedly different from the full four quadrants gauze packing of liver in hemostatic effect, with no CELOX clot formation in other organs.

Regional hypothermia attenuates secondary-injury caused by time-out application of tourniquets following limb fragments injury combined with hemorrhagic shock.

BACKGROUND: Tourniquet is the most widely used and effective first-aid equipment for controlling hemorrhage of injured limb in battlefield. However, time-out application of tourniquets leads to ischemic-necrosis of skeletal muscles and ischemia-reperfusion injury. Regional hypothermia (RH) on wounded limb can relieve the injury on local tissue and distant organs. We aimed to investigate the protective effects of RH on rabbits' limbs injured by a steel-ball combined with hemorrhagic-shock, and then employed tourniquet over-time, tried to identify the optimal treatment RH. METHODS: Thirty rabbits were randomly divided into 5 groups. All rabbits were anesthetized, intubated femoral artery and vein in right-hind limbs. Sham operation group (Sham): only femoral arteriovenous cannula in right-hind limb. None RH group (NRH): rabbits were intubated as Sham group, then the soft tissues of rabbits' left-hinds were injured by a steel-ball shooting, and were exsanguinated until shock, then bundled with rubber tourniquets for 4 h. Three RH subgroups: rabbits were injured as mentioned above, the injured limbs were bundled with rubber tourniquets and treated with different temperature (5 ± 1 °C, 10 ± 1 °C, and 20 ± 1 °C, respectively) for 4 h. The injury severity of lung and regional muscle was assessed by histologic examination. Activity of adenosine triphosphatase (ATPase) and content of malondialdehyde (MDA) in muscle, inflammatory cytokines, myoglobin, creatine kinase-MM (CK-MM), Heme, Heme oxygenase 1 (HO-1), lactic acid (Lac), and lectrolyte ion in serum were detected. RESULTS: Following with RH treatment, the injury of lung and local muscle tissue was alleviated evidencing by mitigation of histopathological changes, significant decrease of water-content and MDA content, and increase of ATPase activity. Lower level of Lac, Potassium (K+), inflammatory cytokines, Heme, CK-MM, myoglobin content, and higher level of Calcium (Ca2+), HO-1 content were shown in RH treatment. 10 °C was the most effective RH to increase ATPase activity, and decrease MDA, myoglobin, CK-MM content. CONCLUSION: Transient RH (4 h) had a "long-term mitigation effects" (continued for 6 h) on time-out application of tourniquet with the fluid resuscitation and core temperature maintenance, and the most effective temperature for reducing the side effects on tourniquet time-out application was 10 °C.

Experimental Study of Thoracoabdominal Injuries Suffered from Caudocephalad Impacts Using Pigs.

To know the caudocephalad impact- (CCI-) induced injuries more clearly, 21 adult minipigs, randomly divided into three groups: control group (n = 3), group I (n = 9), and group II (n = 9), were used to perform the CCI experiments on a modified deceleration sled. Configured impact velocity was 0 m/s in the control group, 8 m/s in group I, and 11 m/s in group II. The kinematics and mechanical responses of the subjects were recorded and investigated. The functional change examination and the autopsies were carried out, with which the injuries were evaluated from the Abbreviated Injury Scale (AIS) and the Injury Severity Score (ISS). The subjects in group I and group II experienced the caudocephalad loading at the peak pelvic accelerations of 108.92 ± 58.87 g and 139.13 g ± 78.54 g, with the peak abdomen pressures, 41.24 ± 16.89 kPa and 63.61 ± 65.83 kPa, respectively. The injuries of the spleen, lung, heart, and spine were detected frequently among the tested subjects. The maximal AIS (MAIS) of chest injuries was 4 in group I and 5 in group II, while both the MAIS of abdomen injuries in group I and group II were 5. The ISS in group II was 52.71 ± 6.13, significantly higher than in group I, 26.67 ± 5.02 (p < 0.05). The thoracoabdomen CCI injuries and the mechanical response addressed presently may be useful to conduct both the prevention studies against military or civilian injuries.

Therapeutic Whole-body Hypothermia Protects Remote Lung, Liver, and Kidney Injuries after Blast Limb Trauma in Rats.

BACKGROUND: Severe blast limb trauma (BLT) induces distant multiple-organ injuries. In the current study, the authors determined whether whole-body hypothermia (WH) and its optimal duration (if any) afford protection to the local limb damage and distant lung, liver, and kidney injuries after BLT in rats. METHODS: Rats with BLT, created by using chartaceous electricity detonators, were randomly treated with WH for 30 min, 60 min, 3 h, and 6 h (n = 12/group). Rectal temperature and arterial blood pressure were monitored throughout. Blood and lung, liver, and kidney tissue samples were harvested for measuring tumor necrosis factor-α, interleukin-6 and interleukin-10, myeloperoxidase activity, hydrogen sulfide, and biomarkers of oxidative stress at 6 h after BLT. The pathologic lung injury and the water content of the lungs, liver, and kidneys and blast limb tissue were assessed. RESULTS: Unlike WH for 30 min, WH for 60 min reduced lung water content, lung myeloperoxidase activity, and kidney myeloperoxidase activity by 10, 39, and 28% (all P < 0.05), respectively. WH for 3 h attenuated distant vital organs and local traumatic limb damage and reduced myeloperoxidase activity, hydrogen peroxide and malondialdehyde concentration, and tumor necrosis factor-α and interleukin-6 levels by up to 49% (all P < 0.01). Likewise, WH for 6 h also provided protection to such injured organs but increased blood loss from traumatic limb. CONCLUSIONS: Results of this study indicated that WH may provide protection for distant organs and local traumatic limb after blast trauma, which warrants further study.

Regional traumatic limb hypothermia attenuates distant hepatic and renal injury following blast limb trauma in rats.

BACKGROUND: Blast limb injury was reported to result in distant organ injury including the lungs, which can be attenuated with transient regional hypothermia (RH) to the injured limb. We aimed to further study hepatic and renal injuries following blast limb trauma and also to evaluate the protective effects of regional traumatic limb hypothermia on such injuries in rats. METHODS: Blast limb trauma (BLT) was created using chartaceous electricity detonators in anesthetized male Sprague-Dawley rats. The BLT rats were randomly allocated to undergo regional traumatic limb hypothermic treatment (RH) for 30 minutes, 60 minutes, or 6 hours immediately after the onset of blast or without RH (n = 8 per group). The severity of hepatic and renal injury was assessed through histologic examination and water content (wet/dry weight) in all animals 6 hours later. The level of plasma tumor necrosis factor α (TNF-α), interleukin 6, hydrogen sulfide (H2S), and myeloperoxidase (MPO) together with hepatic and renal MPO, malondialdehyde (MDA), superoxide dismutase, and total antioxidant capacity were measured 6 hours after the blast injury. RESULTS: Following BLT, hepatic injury was evidenced by histopathologic changes, increased water content, as well as plasma alanine aminotransferase and aspartate aminotransferase. Renal histopathologic but not functional changes were also found. RH treatment for all durations attenuated this distant renal injury, but only RH treatment for 60 minutes and 6 hours attenuated distant hepatic injury following BLT. RH treatment for all durations decreased plasma TNF-α and interleukin 6, reduced liver and kidney MPO activity and kidney MDA, and elevated superoxide dismutase and total antioxidant capacity in both liver and kidneys. RH treatment for 60 minutes is the most effective duration to reduce hepatic MPO activity, plasma TNF-α, and kidney MDA. CONCLUSION: This study indicates that BLT-induced distant renal and hepatic injury could be attenuated by RH treatment through reduction of cytokine release and inhibition of neutrophil accumulation and oxidative stress.

Transient regional hypothermia applied to a traumatic limb attenuates distant lung injury following blast limb trauma.

OBJECTIVES: Explosive traumatic injury to an extremity may lead to both local and distant organ injury. Regional traumatic tissue hypothermia has been reported to offer systemic protection; here we investigated the protective effects of regional limb hypothermia on local tissue trauma and the lungs. Furthermore, the optimal duration of regional traumatic limb hypothermic treatment was also evaluated. DESIGN: Prospective, controlled, animal study. SETTING: University research laboratory. SUBJECTS: Adult male Sprague-Dawley rats. INTERVENTIONS: Anesthetized rats were randomized to sham, blast limb trauma, sham and regional hypothermia for 30 minutes, and blast limb trauma and regional hypothermia for 30 minutes, 60 minutes, and 6 hours. Blast limb trauma was created using chartaceous electricity detonators. MEASUREMENTS AND MAIN RESULTS: Distant lung and local tissue injury following blast limb trauma were attenuated by regional traumatic limb hypothermic treatment for 30 minutes, 60 minutes, and 6 hours reflected by reduced lung histopathological changes and water content. Regional traumatic limb hypothermic treatment for 60 minutes and 6 hours failed to further attenuate distant lung and local tissue injury compared with regional traumatic limb hypothermic treatment for 30 minutes. Inhibition of cystathionine gamma-lyase/hydrogen sulfide was reduced by regional traumatic limb hypothermic treatment for 30 minutes in blast limb trauma rats. A surrogate of neutrophil accumulation, myeloperoxidase activity, and release of tumor necrosis factor-α and interleukin-6 were also attenuated by regional traumatic limb hypothermic treatment for 30 minutes in blast limb trauma rats. Oxidative stress was alleviated by regional traumatic limb hypothermic treatment for 30 minutes evidenced by reduction of hydrogen peroxide and malondialdehyde and an increase of superoxide dismutase and glutathione in blast limb trauma rats. CONCLUSIONS: Our data indicate that regional traumatic limb hypothermic treatment for 30 minutes offers both local protection for traumatic tissue and systemic protection for the lungs, which is likely associated with restoration of the cystathionine gamma-lyase/hydrogen sulfide pathway and inhibition of the inflammatory response and oxidative stress.

Characteristics and mechanisms of cardiopulmonary injury caused by mine blasts in shoals: a randomized controlled study in a rabbit model.

BACKGROUND: Because the characteristics of blast waves in water are different from those in air and because kinetic energy is liberated by a pressure wave at the water-air interface, thoracic injuries from mine blasts in shoals may be serious. The aim of the present study was to investigate the characteristics and mechanisms of cardiopulmonary injury caused by mine blasts in shoals. METHODS: To study the characteristics of cardiopulmonary injury, 56 animals were divided randomly into three experimental groups (12 animals in the sham group, 22 animals in the land group and 22 animals in the shoal group). To examine the biomechanics of injury, 20 animals were divided randomly into the land group and the shoal group. In the experimental model, the water surface was at the level of the rabbit's xiphoid process, and paper electric detonators (600 mg RDX) were used to simulate mines. Electrocardiography and echocardiography were conducted, and arterial blood gases, serum levels of cardiac troponin I and creatine kinase-MB and other physiologic parameters were measured over a 12-hour period after detonation. Pressures in the thorax and abdomen and the acceleration of the thorax were measured. CONCLUSION: The results indicate that severe cardiopulmonary injury and dysfunction occur following exposure to mine blasts in shoals. Therefore, the mechanisms of cardiopulmonary injury may result from shear waves that produce strain at the water-air interface. Another mechanism of injury includes the propagation of the shock wave from the planta to the thorax, which causes a much higher peak overpressure in the abdomen than in the thorax; as a result, the abdominal organs and diaphragm are thrust into the thorax, damaging the lungs and heart.

Sodium Hydrosulphide alleviates remote lung injury following limb traumatic injury in rats.

Hydrogen sulphide (H2S) was found to attenuate ventilator or oleic acid induced lung injury. The aim of this study was to explore the effects of exogenous H2S donor, sodium Hydrosulphide (NaHS), on lung injury following blast limb trauma and the underlying mechanisms. For in vitro experiments, pulmonary micro-vessel endothelial cells (PMVECs) were cultured and treated with NaHS or vehicle in the presence of TNF-α. For in vivo, blast limb traumatic rats, induced by using chartaceous electricity detonators, were randomly treated with NaHS, cystathionine gamma-lyase inhibitor (PAG) or vehicle. In vitro, NaHS (100 µM) treatment increased PMVECs viability and decreased LDH release into culture media after tumor necrosis factor (TNF) α challenge. In addition, NaHS treatment prevented the increase of nitric oxide, Intercellular Adhesion Molecule 1(ICAM-1) and interleukin (IL)-6 production and inducible nitric oxide synthase activation induced by TNF-α. Knock-down of NF-E2-Related Factor 2 (Nrf2) partially abolished the protective effect of NaHS. In vivo, NaHS treatment significantly alleviated lung injury following blast limb trauma, demonstrated by a decreased histopathological score and lung water content. Furthermore, NaHS treatment reversed the decrease of H2S concentration in plasma, prevented the increase of TNF-α, IL-6, malondialdehyde and myeloperoxidase, increased the Nrf2 downstream effector glutathione in both plasma and lungs, and reversed the decrease of superoxide dismutase in both plasma and lungs induced by blast limb trauma. Our data indicated that NaHS protects against lung injury following blast limb trauma which is likely associated with suppression of the inflammatory and oxidative response and activation of Nrf2 cellular signal.

Lung injury following lower extremity blast trauma in rats.

BACKGROUND: Lower extremity blast trauma is a common injury during armed conflict and after terrorist attacks with a high mortality, which is likely associated with distant vital organ injury. The current study aimed to investigate the underlying mechanisms of remote lung injury after blast lower extremity trauma. METHODS: Sprague-Dawley rats were randomly divided into two groups: sham and blast. The blast group underwent blast trauma to the left hind limb using chartaceous electricity detonators, which was then subdivided into the time at which they were sacrificed: 0.5, 1, 3, and 6 hours. The sham group was also subdivided into the baseline control and time course groups. The baseline group was sacrificed 0.5 hours after artery cannulation and the time course at 6 hours after sham blast. The lungs were harvested for histologic analysis and water content measurement. Blood samples were harvested at each end of experiment and analyzed for cytokines, myeloperoxidase, malondialdehyde, and superoxide dismutase and cystathionine γ-lyase activity and hydrogen sulfide. RESULTS: Blast hind limb trauma induced alveolar injury and cell infiltration, together with an increase in lung water content, in a time-dependent manner. Plasma and lung levels of proinflammatory cytokines, tumor necrosis factor-α and interleukin 6, and malondialdehyde, were found to be significantly increased in conjunction with a rise in myeloperoxidase and a concurrent fall in superoxide dismutase, cystathionine γ-lyase, and hydrogen sulfide. CONCLUSION: Our data demonstrated that blast limb trauma causes remote lung injury, which is likely associated with remarkable inflammatory response, oxidative stress, and depletion of protective mechanisms.

Neurological, functional, and biomechanical characteristics after high-velocity behind armor blunt trauma of the spine.

BACKGROUND: Behind armor blunt trauma (BABT) describes a nonpenetrating injury to the organs of an individual wearing body armor. The aim of this study was to investigate the neurologic and functional changes that occur in the central nervous system after high-velocity BABT of the spine as well as its biomechanical characteristics. METHODS: This study evaluated 28 healthy adult white pigs. Animals were randomly divided into three experimental groups: (1) 15 animals (9 in the exposed group and 6 in the control group) were tested for neurologic changes; (2) 10 animals (5 in the exposed group and 5 in the control group) were used for studies of cognitive function; (3) and 3 animals were used for examination of biomechanics. In the group tested for neurologic changes, 9 anesthetized pigs wearing body armor (including a ceramic plate and polyethylene body armor) on the back were shot on the eighth thoracic vertebrae (T8) with a 5.56-mm rifle bullet (velocity appropriately 910 m/s). As a control, six pigs were shot with blank ammunition. Ultrastructural changes of the spinal cord and brain tissue were observed with light and electron microscopy. Expression levels of myelin basic protein, neuron-specific enolase (NSE), and glial cytoplasmic protein (S-100B) were investigated in the serum and cerebrospinal fluid using enzyme-linked immunosorbent assays. Electroencephalograms (EEGs) were monitored before and 10 minutes after the shot. Pressures in the spine, common carotid artery, and brain were detected. Acceleration of the 10th vertebrae (T10) was tested. Finally, cognitive outcomes between exposed and control groups were compared. RESULTS: Neuronal degeneration and nerve fiber demyelination were seen in the spinal cord. The concentrations of neuron-specific enolase, myelin basic protein, and S-100B were significantly increased in the serum and cerebrospinal fluid 3 hours after trauma (p < 0.05). The electroencephalogram was suppressed within 3 to 6 minutes after trauma. The pressure detected in the brain was higher than that detected in the common carotid artery (p < 0.01). The trauma resulted in paralysis of two hind limbs and in cognitive dysfunction. CONCLUSION: The results from our animal model indicate that high-velocity BABT of the spine generates high pressure and acceleration in the spine, induces varying degrees of paralysis of hind limbs, and disturbs cerebral function. The neuronal degeneration caused by the pressure wave may be one of the important pathologic events involved in the development of trauma-related complications.

Low- and high-dose hydrogen peroxide regulation of transcription factor NF-E2-related factor 2.

BACKGROUND: Reactive oxygen species (ROS) may play both physiological and pathophysiological roles. Transcription factor NF-E2-related factor 2 (Nrf2) regulates antioxidant response element (ARE)-mediated genes expression and coordinates induction of chemoprotective proteins in response to physical and chemical stresses. The exact role of Nrf2 in cellular responses to different levels of oxidative stresses remains unknown. METHODS: Rat pulmonary microvascular endothelial cells were cultured and treated with 0 mmol/L, 0.125 mmol/L, 0.25 mmol/L, 0.5 mmol/L, 1.0 mmol/L and 2.0 mmol/L hydrogen peroxide solution for 2 hours. Nrf2 gene expression was assayed by reverse transcription-PCR, Nrf2-ARE binding activity was assayed with electrophoretic mobility shift assay (EMSA), and localization of Nrf2 was detected with immunohistochemistry. RESULTS: Low and moderate (0.125 mmol/L, 0.25 mmol/L and 0.5 mmol/L) doses hydrogen peroxide exposure of rat pulmonary microvascular endothelial cells led to the nuclear accumulation of Nrf2, increased activity of transcription regulation and up-regulation of ARE-medicated gene expression. In contrast, high doses of hydrogen peroxide (1 mmol/L, 2 mmol/L) exposure of the cells led to the nuclear exclusion of Nrf2, decreased activity transcription regulation and down-regulation of ARE-mediated gene expression. CONCLUSION: Low and moderate doses of hydrogen peroxide play protective roles by increasing transcription activity of Nrf2, whereas high- dose hydrogen peroxide plays a deleterious role by decreasing transcription activity of Nrf2.

A Pilot Study of Ultrasonically-assisted Treatment of Residual Burn Wounds .

UNLABELLED: Objective. To evaluate the use of a noninvasive, low-frequency ultrasound device to treat residual burn wounds as an adjunct to regular wound dressing therapy. METHODS: Nineteen patients with 38 residual wounds (served as self control) with an average post-burn duration of 94.6 days were recruited. Low-frequency ultrasound at 40 kHz was delivered in the ultrasonic group by a handheld probe, using normal saline as the irrigation medium. The control group had dressings changed with saline used as the coupling medium. Each wound was treated for 2 weeks (a total of 7 treatments; once every 2 days). Bacterial colony counts were done before the first and then after the fourth treatment. Serial color photographs were taken to evaluate the wound response at each visit. Healing time and percentage closure were determined. RESULTS: Symptomatic relief (pain and odor reduction) was achieved in all patients. The healing percentage for the wounds treated with ultrasound was 100%. The healing rate in the treatment group was 84%, while the healing rate was 71.46% ± 31.06%; both were significantly higher compared to the control wounds (P < 0.01). The bacterial clearance rate in the ultrasound group (82.85 ± 19.13) increased significantly compared to the control group (35.55 ± 16.99). There were no major complications with the treatment, which was relatively painless. CONCLUSION: The application of low-frequency ultrasound treatment may heal residual burn wounds when a nonsurgical dressing change protocol has failed. The significant decrease in wound bioburden was definitely related to the use of the ultrasound treatment. No adverse reactions to the ultrasound treatment were found during the study. .

[Effect of substance P on the migration and differentiation of cultured epidermal stem cells to hair follicle in vitro].

OBJECTIVE: To investigate the effect of substance P (SP) on the migration and differentiation of epidermal stem cells (ESCs) to hair follicle, and its mechanism. METHODS: ESCs were cultured in vitro, and confirmed by positive staining of K19 and integrin beta1 with immunohistochemistry. SP was added into the culture of ESCs which were labelled with 5-BrdU, and the cell cultures were divided into control, 10(-5) mol/L SP, 10(-6) mol/L SP, and 10(-7) mol/L SP groups according to the different doses of SP addition. Cell suspension (0.3 ml) containing SP was injected into the dermis in the back of nude mice. Repeated injection of the equal amount of cell suspension in the same place was carried out on 4, 7, 10 and 14 days after first injection. The cells in control group received the same treatment but without SP. The skin specimens in the area of cell culture injection and the normal skin remote from cell injection were harvested for the histological examination and hair follicle counting by immunohistochemistry and electronmicroscope 28 days after injections. RESULTS: Hair follicles in scattered distribution were observed in 10(-5) mol/L SP group,but some of them were defective in development. Hypoplasic hair follicle and a few hair follicles with distinct structure were observed in 10(-5) mol/L SP group. Large amounts of hair follicles with distinct structure in deep dermis and subcutaneous tissue were observed in 10(-6) mol/L SP, 10(-7) mol/L SP groups, and some of them showed positive staining of brown BrdU in the hair root, and most of them showed positive staining of brown beta-catenin, but a few of them showed developmental defect. In contrast, hypoplasia of hair follicle underneath epidermis and deep layer of dermis with positive staining of brown BrdU and beta-catenin in epidermis were observed in control group. The number of hair follicles in 10(-6)mol/L SP, 10(-7) mol/L SP groups [(1.9 +/- 1.2 ), (1.3 +/- 0.8)] was obviously less than that in control group [(10. 5 +/- 1.2), P < 0.01]. CONCLUSION: SP can induce ESCs to migrate from the basal layer into hair follicle, and this effect is dependent on the SP concentration. SP can also elevate the expression of beta-catenin in ESCs,which induces its differentiation to hair follicles.

Surgical treatment for rabbits' femoral arteries subjected to gunshot wounds combining with seawater immersion.

OBJECTIVE: To investigate the surgical treatment methods and evaluate the outcome of gunshot wounds combining with seawater immersion in rabbits' femoral arteries. METHODS: One hundred healthy New Zealand white rabbits (either sex, 3.14 kg+/-0.61 kg in weight) were randomly divided into a seawater immersion group (n=50) and a simple injury group (n=50). The unilateral femoral arteries of all the rabbits were injured by 0.38 g steel spheres with velocity of 600-800 m/s fired by a 7.62 mm rifle. The rabbits in the seawater immersion group were immersed in seawater (saline content of 2.54%, pH 8.2-8.4, and at 21 degrees C) for 60 minutes but those in the simple injury group were not. After the injured segment (observed by naked eyes) of the femoral artery was excised, the blood flow restoration was reconstructed by direct end-to-end anastomosis, reversed autogenous venous grafting or cryopreserved arterial allografting, according to the length of the arterial defects. At 24 hours, and 7, 14 and 21 days after operation, the blood flow was examined. Operative exploration was performed for the animals with partly or fully obstructed blood flow. The tissues around the anastomosis sites and the grafts were harvested for pathological observation under a light microscope and an electron microscope. RESULTS: In the rabbits with completely transected injury, the unobstructed rates in the first 3 weeks after operation were 80.00% in the seawater immersion group and 86.67% in the single injury group, and no significant difference was found between the two groups (P>0.1). In the rabbits with arterial contusion injury, the unobstructed rates in the first 3 weeks after operation were 86.67% in the seawater immersion group and 82.35% in the single injury group, and no significant difference was found between the two groups (P>0.1). Most thrombosis occurred in the first operative week. Atypical endothelial cells were detected at the anastomosis sites at the first operative week, and the anastomosis sites were lined with endothelial cells in 3 weeks postoperatively. CONCLUSIONS: During the surgical treatment for gunshot wounds combining with seawater immersion, resection of the grossly-injured artery and routine artery reconstruction can obtain satisfactory outcome. Homologous artery is a kind of vascular graft with certain applied value.

Comparative study on effects of burn-blast combined injury and burn-firearm combined injury complicated with seawater immersion on vascular endothelial cells.

OBJECTIVE: To comparatively study the effects and mechanisms of burn-blast combined injury and burn-firearm combined injury complicated with seawater immersion on vascular endothelial cells. METHODS: A total of 40 healthy adult hybrid dogs of both sexes, weighing 12-15 kg, were used in this study. Randomly-selected 20 dogs were established as models of burn-blast combined injury (the burn-blast injury group) and the other 20 dogs as models of burn-firearm combined injury (the burn-firearm injury group). Then the wounds of all the dogs were immediately immersed in seawater for 4 hours, and then they were taken out from the seawater. Blood samples were withdrawn from the central vein of the dogs before injury, and at 4, 7, 10, 20, and 28 hours after injury to measure the circulating endothelial cells and the von Willebrand factor. RESULTS: Circulating endothelial cells increased significantly at 4 hours after injury in all the dogs. But they reached peak at 7 hours after injury in the burn-blast injury group and at 28 hours after injury in the burn-firearm injury group. The changes of circulating endothelial cells in the burn-blast injury group were significantly different from those in the burn-firearm injury group at 4, 7, 20, and 28 hours after injury (P < 0.01). The von Willebrand factor reached peak at 4 hours after injury in the burn-blast injury group and at 28 hours in the burn-firearm injury group. The changes of von Willebrand factor in the burn-blast injury group were significantly different from those in the burn-firearm injury group at 4, 20, and 28 hours after injury (P < 0.01). CONCLUSIONS: In burn-blast injury combined with seawater immersion, the vascular endothelial cells changed most significantly at 4 hours or 7 hours after injury, while burn-firearm injury combined with seawater immersion have the same at 20 hours or 28 hours after injury.

Pathological study of rabbits' femoral arteries subjected to gunshot wounds combining with seawater immersion.

OBJECTIVE: To investigate pathological characteristics of gunshot wounds concomitant seawater immersion in rabbits' femoral arteries. METHODS: Thirty rabbits were divided randomly into 3 groups: simple gunshot-wound group (Group I, n = 10), gunshot wound with seawater immersion for 30 mins (Group II, n = 10), and 60 mins group (Group III, n = 10). Femoral arteries were impacted by 0.38 g steel spheres fired with a 7.62 mm rifle. After being wounded, rabbits in Groups II and III were immersed in seawater for 30 or 60 mins, but those in Group I were not. At 2, 4, 6, 8, 12 hours following injury, a 40 mm segment of the artery on each side of the gunshot point were excised and observed by light and electron microscopy. RESULTS: The patterns of arterial injuries were mainly contusion and transection. Completely transected artery was classified as primary-wound-tract area, contused area and shocked area. Compared with those in Group I, the primary-wound-tract and contused areas in Group II manifested obvious swelling in the arterial wall especially at the outside 2/3 of the media. Vacuolar structures were often seen in smooth muscle cells of the media. Intercellular space among the smooth muscle cells were filled with homogeneous acidophilic substances. Deep rugae among endothelial cells flattened or rugal folds lost their longitudinal orientation, and marked fibrin and platelet deposition were noticed. No significant difference was detected between Group II and III. The pathological changes in the shocked area were similar in 3 groups. CONCLUSIONS: For gunshot wounds concomitant seawater immersion in rabbits' femoral arteries, there was a marked swelling of cells and intercellular space in primary-wound-tract area and contusion area. The influence of these pathological changes on surgical reparation deservers further study.

[Changes in neuropeptide substance P and calcitonin gene-related peptide in scarless wound healing in fetal rabbit skin].

OBJECTIVE: To explore the role of the neuropeptide in fetal scarless wound healing. METHODS: The animal models were replicated in which a full-thickness wound was inflicted on the back of rabbit fetuses at 22 days gestation (term=31 days). The progress of wound healing was observed on micro-and macro-levels at the 1 st, 2 nd, 3 rd, 5 th, 7 th, 14 th post-injury days respectively. The expression level of substance P(SP) and calcitonin gene-related peptide (CGRP) during wound healing was assessed by immunohistochemistry staining. RESULTS: The cutaneous wounds in fetal rabbits healed more rapidly than that in adult and without the formation of scar. The expression of SP and CGRP of wound decreased in fetal rabbit at the early stage post-injury, down to the lowest levels on the 2 nd post-injury day (75%, 80%, vs. fetal control, both P<0.01), then increased gradually, up to the normal levels. The expression of SP and CGRP of wound decreased in adult rabbit at the early stage post-injury, down to the lowest levels on the post-injury 1 st day (60%, 76%, vs. adult control, both P<0.01), then increased quickly, up to a higher level than normal group, reaching the peak on the post-injury 7th day(168%, 126%, vs. adult control, both P<0.01), then returned to the normal levels. CONCLUSION: The low level of neuropeptide may contribute to scarless wound healing in fetal rabbit.

[Comparison of resuscitation with Parkland formula and with improved protocol on hemodynamics in projectile-burn combined wound in dogs with seawater immersion].

OBJECTIVE: To compare hemodynamic effects of resuscitation with Parkland formula or with the improved protocol on projectile-burn combined wound in dogs with seawater immersion. METHODS: A model of projectile-burn combined wound in dogs with seawater immersion was reproduced, and 20 dogs were randomized into three groups: projectile-burn combined wound with seawater immersion (immersion group, n=8), Parkland formula resuscitation (lactated Ringer's solution 4 ml/kg per 1%total body surface area for 24 hours, standard resuscitation group, n=6), and improved protocol groups (lactated Ringer's solution 2.5 ml/kg per 1% total body surface area colloid solution 6% hetastarch 0.5 ml/kg per 1% total body surface area for 24 hours, improved group, n=6). Changes of hemodynamics and central temperature (CT) before injury, and 4, 7, 10, 20 and 28 hours after injury were observed. The mortality was observed. RESULTS: After resuscitation with Parkland formula, CT as well as hemodynamic indexes and amount of urine were improved, but central venous pressure (CVP) and the amount of urine were higher in early period of resuscitation. CVP was (14.7+/-3.1)cm H2O and the amount of urine was (2.38+/-0.18)ml.h(-1).kg(-1) at 7 hours after injury. Hemodynamics was not stable during later period of experiment. After resuscitation with the improved protocol, the hemodynamics ameliorated better than resuscitation with Parkland formula. No animals died in improved group, but 4 and 1 died respectively in immersion group and standard resuscitation group. CONCLUSION: Fluid resuscitation according to the improved protocol is more suitable for projectile-burn combined wound in dogs with seawater immersion than resuscitation with Parkland formula.

[Effects of substance P on granulation tissue fibroblasts proliferation and expression of basic fibroblast growth factor mRNA].

OBJECTIVE: To explore the proliferation-promoting effect of sensory neuropeptide substance P (SP) on the cultured granulation tissue fibroblasts in vitro and its regulative effect on the gene expression of basic fibroblast growth factor (bFGF) mRNA. METHODS: The proliferation-promoting effect of cultured granulation tissue fibroblasts was observed by means of MTT; the regulative effect of SP on gene expression of fibroblast bFGF by RT-PCR. The time and dose-efficiency relations were also observed. RESULTS: There was a significant proliferation-promoting effect of SP on the cultured granulation tissue fibroblasts in vitro in a remarkable dose-dependent fashion. However, bFGF antibody only partly exerted its inhibitive effect. SP could induce the bFGF mRNA expression of the fibroblasts at the 3rd and 6th hour (P < 0.01). SP could promote the bFGF mRNA expression of the fibroblasts in the concentration of 10(-9) - 10(-5) mol/L and peaked in the concentration of 10(-7) mol/L. CONCLUSIONS: SP has a significant proliferation-promoting effect on the granulation tissue fibroblasts, which is correlated with SP inducing bFGF mRNA expression of fibroblasts.