Dexmedetomidine Attenuates Spinal Cord Ischemia-reperfusion Injury in Rabbits by Decreasing Oxidation and Apoptosis.

BACKGROUND: In brain ischemia, dexmedetomidine (DEX) prevents glutamate and norepinephrine changes, increases nerve conduction, and prevents apoptosis, but the mechanisms are poorly understood. OBJECTIVE: This study aimed at examining the protective effect and function of DEX on spinal cord ischemia-reperfusion injury (SCIRI) and whether the effect is mediated by oxidative stress and apoptosis (with the involvement of Bcl-2, Bax, mitochondria, and Caspase-3). METHODS: Rabbits were randomly divided into the sham group, infusion/reperfusion (I/R) group, and DEX+I/R group. SCIRI was induced by occluding the aorta just caudal to the left renal artery for 40 min, followed by reperfusion. DEX was continuously administered for 60 min before clamping. The animals were evaluated for neuronal functions. Spinal cord tissues were examined for SOD activity and MDA content. Bcl-2, Bax, and Caspase-3 expressions were detected by western blotting. TUNEL staining was used for apoptosis. RESULTS: With the extension of reperfusion time, the hind limbs' neurological function in the DEX+I/R group gradually improved, but it became worse in the I/R group (all P<0.05 vs. the other time points within the same groups). Compared with I/R, DEX decreased MDA and increased SOD (P<0.01), upregulated Bcl-2 protein expression (P<0.05), downregulated Bax expression (P<0.05), decreased caspase-3 expression (P<0.05), prevented histological changes in neurons, and decreased the apoptotic index of the TUNEL labeling (P<0.05). CONCLUSION: DEX could attenuate SCIRI in rabbits by improving the oxidative stress status, regulating the expression of apoptosis-related proteins, and decreasing neuronal apoptosis.

Intravenous Infusion of Dexmedetomidine Combined Isoflurane Inhalation Reduces Oxidative Stress and Potentiates Hypoxia Pulmonary Vasoconstriction during One-Lung Ventilation in Patients.

Inhalation anesthetic isoflurane inhibits hypoxia pulmonary vasoconstriction (HPV), while dexmedetomidine (Dex) could reduce the dose of isoflurane inhalation and potentiate HPV, but the mechanism is unclear. Inhibition of reactive oxygen species (ROS) production can favor HPV during one-lung ventilation (OLV). Similarly, nitric oxide (NO), an important endothelium-derived vasodilator in lung circulation, can decrease the regional pulmonary vascular resistance of ventilated lung and reduce intrapulmonary shunting. We hypothesized that Dex may augment HPV and improve oxygenation during OLV through inhibiting oxidative stress and increasing NO release. Patients undergoing OLV during elective thoracic surgery were randomly allocated to either isoflurane + saline (NISO, n = 24) or isoflurane + dexmedetomidine (DISO, n = 25) group. Anesthesia was maintained with intravenous remifentanil and inhalational isoflurane (1.0-2.0%), with concomitant infusion of dexmedetomidine 0.7 µgkg(-1)h(-1) in DISO and saline 0.25 mL kg(-1)h(-1) in NISO group. Hemodynamic variables or depth of anesthesia did not significantly differ between groups. Administration of Dex significantly reduced Qs/Qt and increased PaO2 after OLV, accompanied with reduced lipid peroxidation product malondialdehyde and higher levels of SOD activity as well as serum NO (all P < 0.05 DISO versus NISO). In conclusion, reducing oxidative stress and increasing NO release during OLV may represent a mechanism whereby Dex potentiates HPV.

The effect of safflower yellow on spinal cord ischemia reperfusion injury in rabbits.

Safflower yellow (SY) is the safflower extract and is the one of traditional Chinese medicine. The aim of the present work was to investigate the effect of SY on spinal cord ischemia reperfusion injury (SCIRI) in rabbits. The models of spinal cord ischemia reperfusion (SI/R) were constructed, and the degree of the post-ischemic injury was assessed by means of the neurological deficit scores and plasma levels of lipid peroxidation reactioin and neuronal morphologic changes. SCIRI remarkably affected the functional activities of the hind limbs and activated lipid peroxidation reaction. SY could attenuate apoptosis and SCIRI by enhancing Bcl-2 expression and inhibiting Bax and caspase-3 activation.

Nondestructive identification for red ink entries of seals by Raman and Fourier transform infrared spectrometry.

Determination of the red ink entries of seals on documents can provide valuable evidences for solving related crimes, distinguishing the truth of artworks, and so establishment of nondestructive approaches would play a key role in forensic analysis and related aspects. Raman and FT-IR spectroscopy have been applied for analyzing 105 kinds of red ink entries on documents. The dye components of the ink entries were identified by FT-Raman and confocal Raman microspectroscopy, and then the ink entries were classified into four groups based on these dye components. The ink entries were further discriminated by their FT-IR spectra according to adsorption peaks of the main components, the relative intensities of the characteristic bands and the profiles of the spectra. The results showed that 70 ink entries out of 105 have been individually identified and the remaining 35 ink entries can be divided into 13 subclasses. Combination of Raman and FT-IR spectroscopic methods can provide a powerful nondestructive discriminating tool for identification of the red ink entries of seals on papers. These approaches would have potential application in archeology, art and forensic science.