A long-term survival rat model of spinal cord ischemia injury: Thoracic aortic occlusion combined with aortic bypass circulation.

OBJECTIVE: This study aims to investigate the methods for rat spinal cord ischemia injury models with a high long-term survival rate. METHODS: The rats were divided into three groups: the treatment group, the control group, and the sham operation group. The treatment group had a blocked thoracic aorta (landing zone 3 by Ishimaru - T11) + aortic bypass circulation for 20 min. In the control group, the thoracic aorta at the landing zone 3 was blocked for 20 min. In the sham operation group, only thoracotomy without thoracic aortic occlusion was performed. The mean arterial blood pressure (MABP) of the thoracic aorta and caudal artery before and after thoracic aortic occlusion was monitored intraoperatively. Spinal cord function was monitored by a transcranial motor evoked potential (Tc-MEP) during the operation. Spinal cord function was evaluated by the BBB scale (Basso, Beattie, & Bresnahan locomotor rating scale) scores at multiple postoperative time points. The spinal cord sections of the rats were observed for 7 days after surgery, and the survival curves were analyzed for 28 days after surgery. RESULTS: After aortic occlusion, the MABP of thoracic aorta decreased to 6% of that before occlusion, and the MABP of caudal artery decreased to 63% of that before occlusion in the treatment group. In the control group, the MABP of both thoracic aorta and caudal artery decreased to 19% of that before occlusion. The Tc-MEP waveform of the treatment group disappeared after 6 min, and that of the control group disappeared after 8 min until the end of surgery. There was no change in the Tc-MEP waveform in the sham operation group. The BBB score of the treatment group decreased more obviously than the control group, and there was a significant difference. There was no decrease in the sham group. Spinal cord sections showed a large number of degeneration and necrosis of neurons, infiltration of inflammatory cells, and proliferation of surrounding glial cells in the treatment group. In the control group, multiple neurons were necrotic. The histology of the sham operation group was normal. The 28-day survival rate of the treatment group was 73.3%, which was higher than the control group (40.0%), and there was a significant difference (p < 0.05). CONCLUSION: Thoracic aortic occlusion combined with aortic bypass is an effective modeling method for rats with accurate modeling effects and high long-term survival rates.

Carthamin Yellow Protects the Heart Against Ischemia/Reperfusion Injury With Reduced Reactive Oxygen Species Release and Inflammatory Response.

Carthamin yellow (CY) is a flavonoid compound isolated from safflower, which is widely used clinically in China. It has various pharmacological effects including promoting blood circulation to remove blood stasis and alleviating pain. Ischemic heart disease is one of the main culprits of illness and death. Here, in this study, ex vivo and in vivo models were used to investigate whether CY reduces ischemia/reperfusion injury. In vitro experiments further verify and explain the potential mechanisms of CY cardioprotective function. Isolated hearts from male rats with or without CY pretreatment before ischemia which underwent 30-minute ischemia followed by 60-minute reperfusion showed that CY pretreatment significantly reduced the infarct size and lactate dehydrogenase release. The in vivo experiments also indicated CY preadministration (i.v.) reduced infarct size and improved the heart function, which was impaired by myocardial ischemia/reperfusion injury. The in vitro model on myocardial cell also showed that CY reduced ischemia/reperfusion injury by reducing the lactate dehydrogenase and reactive oxygen species (ROS) releasing. Eliminating ROS with N-acetylcysteine or preinject CY into rat jugular vein reduces the expression of IL-6, TNF-a, and, especially, IL-1b in an in vivo I/R model. Also, CY pretreatment strongly reduces ischemia/reperfusion-induced NLRP3 up-expression and caspase-1 activation. Our results indicated CY reduced ischemia-reperfusion injury when administered before reperfusion. The reduction in injury is accompanied by a reduced ROS release and decreased inflammatory response.

Aorta-Iliac Bypass in Thoracoabdominal Aortic Aneurysm Repair in Young Chinese Patients.

BACKGROUND: Many surgical methods of thoracoabdominal aortic aneurysm repair (TAAAR) have been introduced over the past several decades, with varying degrees of success. We developed an aorta-iliac bypass technique to treat thoracoabdominal aortic aneurysm (TAAA) in young Chinese patients. The aim of this study is to evaluate the results of this technique intraoperatively and postoperatively. METHODS: From June 2014 to March 2015, 28 patients underwent TAAAR using aorta-iliac bypass technique. A four-branched tetrafurcate graft was used. Two branches of the graft are sutured to bilateral common iliac arteries in an end-to-side fashion. The trunk of the graft was sutured to the proximal descending aorta in an end-to-end fashion. Then aorta-iliac bypass was established, and the lower extremities, viscera organ and spinal cord (SC) obtained perfusion from proximal descending aorta via the bypass graft. The thoracic and abdominal aorta were clamped in a staged fashion. The patent segmental arteries (SAs), and visceral arteries (coeliac trunk, superior mesenteric arteries, and renal arteries) were reattached sequentially. Evoked potential (EP) monitoring was adopted to assess the SC ischaemia throughout the procedure. The postoperative outcomes and follow-up results of this technique were evaluated. RESULTS: There was no in-hospital mortality. Complications included acute kidney dysfunction and pulmonary haemorrhage in one case (3.6%) each. The SAs were reattached in all cases. The EP wave disappeared after proximal descending aorta was clamped, and gradually recovered after the patent SAs reattached. The median follow-up after operation was eight months (range, 1-10 months). There was no delayed neurologic deficit or late death. CONCLUSIONS: Thoracoabdominal aortic aneurysm repair using aorta-iliac bypass may be a simple and safe choice for young Chinese patients with thoracoabdominal aortic aneurysms.