Exogenous Hydrogen Sulfide Protects Against Traumatic Hemorrhagic Shock In Rats

Traumatic hemorrhagic shock (THS) is a type of shock caused by severe trauma with acute circulatory insufficiency. THS is accompanied with the hypovolemia, hypoxemia,apotosis and microcirculatory disturbance, releasing abundant toxic chemical mediators. Resuscitation will also cause ischemia- reperfusion (I/R) damages which will increase the consumption of oxygen,enhance lipid oxidative stress response, stimulate inflammatory cytokines, resulting in dysfunction of cellular oxygen uptake and aggravating tissue damage. It has been reported that treament of reducing oxidative stress damage and inhibiting the outbreak of inflammatory cytokines make sense in the remedy of trauma-hemorrhagic shock.H2S is proved to be extensively involved in many pathophysiological processes of the nervous system, cardiovascular system, respiratory system, digestive system, oxidative stress, cell metabolism, and inflammatory responses. Studies found that H2S can protect vital organs against ischemia-reperfusion injuries, improve the defense against oxidative stress injury, reduce the activation of inflammation, and has significant inhibitory effect on metabolism. However, the effect of H2S on traumatic hemorrhagic shock is still not reported yet.In this study, traumatic hemorrhagic shock model of rats was used to observe the alterations in hemodynamics, cardiac function, tissue injuries, blood gas analysis parameters, and survive rates when giving the exogenous hydrogen sulfide at the beginning of resuscitation. By evaluating the clinical effects of exogenous H2S on traumatic-hemorrhagic shock, we explored the possible mechanisms and expected to provide a new way for the treatments of traumatic hemorrhagic shock.The protective effects of exogenous hydrogen sulfide against trauma-hemorrhagical shock in ratsObjectTo invest the protective effects of exogenous hydrogen sulfide on traumatic hemorrhagic shock in rats.Methods1. Forty-eight male Sprague-Dawely rats were divided into 3 groups randomly as follows: (1) Sham group (n=16); (2) Vehicle group (n=16); (3) NaHS group (n=16). Sham-operated rats underwent all the surgical procedures, except neither hemorrhage nor resuscitation. The rats were given the same volume of vehicle or NaHS solution (28μmol/kg) intraperitoneally at the onset of of the resuscitation in group (2) and (3) respectively. After overnight fast with a free access to water, rats were anesthetized with 3% pentobarbital sodium intraperitoneally (40mg/kg). Trauma hemorrhage and resuscitation model was carried out. Briefly, a 5-cm midline laparotomy was performed to make a soft tissue trauma. The abdominal wound was then closed in two layers with sutures. Polyethylene catheters were put in both femoral arteries and the right femoral vein. The incision sites were then closed. The hemodynamic parameters were measured via one of the arteries using a blood pressure analyzer.Then blood was then withdrawn rapidly to a mean arterial pressure (MAP) of 35–40 mmHg in 10 min through the other artery until the animals could no longer maintain MAP of 35–40 mmHg unless some Ringer lactate solution (RL) was administered. This time and volume were recorded as maximal bleed out (MBO). After the MBO, hypotension was maintained between 35 and 40 mmHg by giving 40% of the MBO volume of RL (about 90 min since the beginning of bleeding). The blood withdrawn was about 60% the same as the total volume (6% of the body weight). The animals were then resuscitated with four times the volume of MBO with RL over 60 minutes in vein. After resuscitation, all the catheters were removed and all wounds were closed with sutures. All the incisions were flushed with lidocaine in order to inhibit pain. At the end of whole procedure, rats was then put in a solo cage with food and water ad libitum.2. Rats were sacrificed 2 hours after resuscitation, and monitored artery mean blood pressure (MAP), heart rate(HR), left ventricular pressure (LVP), positive (+dp/dtmax) and negative (-dp/dtmax) first derivatives of left ventricle pressure. Meanwhile, blood samples were taken to determine the blood gas analysis.3. The serum samples were then analyzed for aspartate aminotransferase (AST), alanine aminotransferase (ALT), blood urea nitrogen (BUN) and serum creatinine (SCr). 4. W/D ratio and IQA of lung tissue were messured to estimate the edema as well as the injury dgree of pulmonary alveoli.5. The changes of H2S, malondialdehyde (MDA), myeloperoxidase (MPO) level and superoxide dismutase (SOD) activity were determined after taking serum samples.6 .The rats were also monitored the variances of survive rates immediaterly and 6h, 24h after resuscitation.7. Histopathological changes of heart, lung, liver and kidney were observed under light microscope at 2 hours after resuscitation among groups.Results1. Compared with sham group, MAP, HR, LVP, +dp/dtmax and -dp/dtmax decreased largely in vehicle group (P<0.05). Compared with vehicle group, NaHS displayed a rise in MAP, LVP, +dP/dtmax and -dP/dtmax (P<0.05).2. Compared with sham group, pH,PaO2 and BE decreased in vehicle group(P<0.05). Compared with vehicle group, NaHS displayed a rise in pH,PaO2 and BE (P<0.05).3. NaHS showed a reverse against the raising AST, ALT, BUN and SC(rserum creatinine)compared with the vehicle group after T-H(P<0.05).4. In the vehicle group, the W/D ratio of lung tissue and IQA increased compared with sham group (P<0.05).But compared with vehicle group, the W/D ratio and IQA in NaHS group decreased largely (P<0.05).5. NaHS also significantly reversed the high mortality caused by T-H after 24 hours.6. The NaHS-treated group showed a remarkable decreasing in MDA and MPO levels in plasma as well as a rise in SOD activity compared with those in vehicle-treated group.7. The histopathological analysis indicated conservation of morphous in heart, liver and kidney in NaHS.group.Conclusions1. NaHS attenuated the depression of cardiac function, promoted the stability of hemodynamic parameters and reversed the acidosis, enhancing survival rate 24 hours after trauma hemorrhage and resuscitation.2. NaHS decreases edema of lung tissue and pulmonary alveoli. NaHS postconditioning also promoted the restoration of hepatic and renal functions.3. Mechanisms for protective effects of NaHS may be associated with the antioxidative damage of hydrogen sulfide on T-H and resuscitation.