Effect of blood flow rate and donor vessel diameter on the patency of carotid venous bypass grafts in dogs

Realtime assessment of vascular occlusion and reperfusion in animal models of intraoperative imaging - a pilot study

Objectives

Intraoperative monitoring of blood flow (BF) remains vital to guiding surgical decisions. Here, we report the use of SurgeON™ Blood Flow Monitor (BFM), a prototype system that attaches to surgical microscopes and implements laser speckle contrast imaging (LSCI) to noninvasively obtain and present vascular BF information in real-time within the microscope's eyepiece.

Methods

The ability of SurgeON BFM to monitor BF status during reversible vascular occlusion procedures was investigated in two large animal models: occlusion of saphenous veins in six NZW rabbit hindlimbs and clipping of middle cerebral artery (MCA) branches in four Dorset sheep brain hemispheres. SurgeON BFM acquired, presented, and stored LSCI-based blood flow velocity index (BFVi) data and performed indocyanine green video angiography (ICG-VA) for corroboration.

Results

Stored BFVi data were analyzed for each phase: pre-occlusion (baseline), with the vessel occluded (occlusion), and after reversal of occlusion (re-perfusion). In saphenous veins, BFVi relative to baseline reduced to 5.2±3.7 % during occlusion and returned to 102.9±14.9 % during re-perfusion. Unlike ICG-VA, SurgeON BFM was able to monitor reduced BFVi and characterize re-perfusion robustly during five serial occlusion procedures conducted 2-5 min apart on the same vessel. Across four sheep MCA vessels, BFVi reduced to 18.6±7.7 % and returned to 120.1±27.8 % of baseline during occlusion and re-perfusion phases, respectively.

Conclusions

SurgeON BFM can noninvasively monitor vascular occlusion status and provide intuitive visualization of BF information in real-time to an operating surgeon. This technology may find application in vascular, plastic, and neurovascular surgery.

Huatuo Zaizao pill promotes functional recovery and neurogenesis after cerebral ischemia-reperfusion in rats

Background

Ischemic stroke is the third leading cause of death in adults worldwide and is the first leading cause of long-term disability. Neurogenesis plays an important role in promoting behavioral recovery after stroke. Huatuo Zaizao pill (HT), a traditional Chinese medicine, has been used clinically in China to promote the rehabilitation after stroke, but the underlying mechanism of action was still unclear. This study is to investigate the effects of HT on the functional recovery in a rat model of cerebral ischemia-reperfusion (I/R) injury, and the potential molecular mechanisms.

Methods

Rats were randomly divided into sham, model with cerebral I/R injury, or HT-treated groups, then administered orally with vehicle (for the sham and model group) or HT (0.5, 1.0, or 2.0 mg/kg) respectively, for 3 or 7 days. Functional recovery was assessed by cylinder test, beam walking test, and adhesive test. Neurogenesis was investigated by double immunofluorescence staining for 5-ethynyl-2-deoxyuridine (EdU) and neuronal nuclear protein (NeuN). The proteins of kinase A (PKA), cAMP response element-binding protein (CREB), and brain-derived neurotrophic factor (BDNF) were assayed by western blotting. The level of BDNF mRNA was evaluated by RT-PCR.

Results

Compared with the model group, treatment with HT significantly promoted functional recovery in I/R injured rats (p < 0.05 or p < 0.01). The generation of new neurons was increased in the HT groups. HT treatment for 3 days increased the level of BDNF mRNA in I/R injured rats. Expression of PKA, phosphorylated CREB, and BDNF were significantly (p < 0.05) increased with the 7-day HT treatment.

Conclusions

These results indicated that HT treatment could promote functional recovery after stroke. HT enhanced the expression of BDNF and increased the level of neurogenesis in cerebral I/R animal, which might be associated with the functional recovery.

Neurological function following cerebral ischemia/reperfusion is improved by the Ruyi Zhenbao pill in a rats

The present study aimed to investigate the effect and underlying mechanisms of the Ruyi Zhenbao pill on neurological function following cerebral ischemia/reperfusion in rats. Male Sprague-Dawley rats underwent middle cerebral artery occlusion following reperfusion. The rats received intragastrically either sodium carboxymethyl cellulose (control and model groups) or Ruyi Zhenbao pill at doses of 0.2, 0.4 or 0.8 g/kg. Neurological function was assessed by cylinder, adhesive and beam-walking tests after 14-day Ruyi Zhenbao pill treatment. Neurogenesis and angiogenesis were detected using immunofluorescence staining. The expression levels of brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF) and vascular endothelial growth factor (VEGF) were determined by enzyme-linked immunosorbent assays. Treatment with 0.4 and 0.8 g/kg Ruyi Zhenbao for 14 days significantly improved neurological function, and increased the number of von Willebrand Factor- and neuronal nuclear antigen-positive cells in the ischemic hemisphere of rats. Ruyi Zhenbao pill treatment also significantly enhanced the expression levels of BDNF, NGF and VEGF in the ischemic hemisphere. The results demonstrated that the Ruyi Zhenbao pill improved neurological function following ischemia in rats. The mechanisms of the Ruyi Zhenbao pill are associated with increasing the expression levels of BDNF, NGF and VEGF, and subsequently promoting neurogenesis and angiogenesis in the ischemic zone.