Objective Emulsified isoflurane (8% ,vol/vol) is a kind of lipid based formation for intravenous administration. The purpose of this study is to evaluate whether emulsified isoflurane induces hemolysis or not in vitro and in vivo. Methods In hemolysis test in vitro, a male rabbit was used to prepare 2% (vol/vol) erythrocyte suspensions for measuring degree of hemolysis of emulsified isoflurane at the doses from 12 to 0. 3 g/L. In hemolysis test in vivo,4 male Beagle dogs were intravenously adminstrated emulsified isoflurane 225.6 mg/kg in 3-5 min. 5 ml samples of venous blood were collected from each dog at 0 min (start of injection) ,5 min,30 min,1 h,2 h,4 h,8 h,1 d,2 d,3 d and 6 d after the adminstration of emulsified isoflurance for measuring erythrocyte morphology,reticulocyte counts, the concentrations of free hemoglobin,haptoglobin,and bilirubin. At the same time, urinary blood, urinary bilirubin and urobilinogen were also measured before and after adminstration. Results In vitro experiment,emulsified isoflurane led to hemolysis at the concentrations from 12 to 1.2 g/L. However,no hemolysis was found at the concentrations from 0. 6 to 0. 3 g/L. In vivo experiment,with the exception of a slight reduction in indirect bilirubin and a mild increase in direct bilirubin at 5 min (P < 0.05 ) , others such as total bilirubin, retculocyte counts, haptoglobin, free hemoglobin,urinary bilirubin,urinary blood, and urinary urobinogen were not significantly different compared with their corresponding values before injection. There was also no significant difference in erythrocyte fragmentations at 0 min,5 min,30 min,1 h,2 h,4 h,8 h,1 d,2 d,3 d and 6 d after injection of emusified isoflurane, and none of macrocytes and nucleated red cells was noted on all blood films. Conclusions Emulsified isoflurane at concentrations recommended for clinical trials did not cause hemolysis in vitro and in vivo.

This study established an aged rat model of cognitive dysfunction using anesthesia with 2%iso-lfurane and 80%oxygen for 2 hours. Twenty-four hours later, Y-maze test results showed that isoflurane significantly impaired cognitive function in aged rats. Gas chromatography-mass spectrometry results showed that isolfurane also signiifcantly increased the levels of N,N-diethy-lacetamide, n-ethylacetamide, aspartic acid, malic acid and arabinonic acid in the hippocampus of isolfurane-treated rats. Moreover, aspartic acid, N,N-diethylacetamide, n-ethylacetamide and malic acid concentration was positively correlated with the degree of cognitive dysfunction in the isolfurane-treated rats. It is evident that hippocampal metabolite changes are involved in the formation of cognitive dysfunction after isoflurane anesthesia. To further verify these results, this study cultured hippocampal neurons in vitro, which were then treated with aspartic acid (100 μmol/L). Results suggested that aspartic acid concentration in the hippocampus may be a biomarker for predicting the occurrence and disease progress of cognitive dysfunction.

Objective To investigate the effects of melatonin on choline acetyltransferase (ChAT) in the hippocampus of rats after isoflurane anesthesia.Methods Sixty male SD rats weighing 390-440 g were randomized into five groups (n =12 each):control group (group C),1％ isoflurane group (group Ⅰ),1％ isoflurane + melatonin group (group IM),2％ isoflurane group (group J) and 2％ isoflurane + melatonin group (group JM).Rats in groups IM and JM received intraperitoneal injection of melatonin (10 mg/kg) for 7 days,and rats in other groups received normal saline.On the 7th day of injection,rats in groups Ⅰ and IM inhaled 1％ isoflurane for 4 hours,and rats in groups J and JM inhaled 2％ isoflurane for 4 hours.One day after anesthesia,all the rats began Morris water maze to assess the learning and memory ability,which was made for continuous 5 days.At the end of probe test,6 rats in each group were randomly selected,blood samples were collected to detect plasma melatonin level,and the hippocampi were removed to evaluate the expression and activity of ChAT.The other rats were sacrificed to perform immunofluorescence to detect ChAT in hippocampal CA1 region and dentate gyrus.Results The plasma melatonin level,and the expression and activity of ChAT were significantly lower in group Ⅰ than in group C (P ＜ 0.01).The escape latency was significantly longer,the probe time was significantly shorter,and the plasma melatonin level and the expression and activity of ChAT were significantly lower in group J than in group C (P ＜ 0.05 or 0.01).The escape latency was significantly shorter,the probe time was significantly longer,and the plasma melatonin level and the expression and activity of ChAT were significantly higher in group IM than in group Ⅰ (P ＜ 0.05 or 0.01).The escape latency was significantly shorter,and the plasma melatonin level and the ChAT activity were significantly higher in group JM than in group J (P＜ 0.05 or 0.01).Conclusion Melatonin can attenuate isoflurane-induced ChAT inhibition and thus improve the cognitive function of rats after isoflurane anesthesia.

Objective To study the effects of isoflurane on ischemia-reperfusion (IR)-induced injury in isolated rat lungs. Methods This study was performed on an isolated buffer-perfused rat lung model. There were four groups: CON group ( n = 6): perfusion for 60 min without ischemia; IR group (n = 6): after perfusion for 30 min, then interruption of perfusion and ventilation for 45 min followed by reperfusion for 30 min; ISO1 group (n = 6 ): 1.38% isoflurane was administered for 30 min before 45 min ischemia, then followed by 30 min reperfusion; ISO2 group (n= 6): 1.38% isoflurane was administered during the period of reperfusion. The Myeloperoxidase (MPO) activity of lung, neutrophils counts, tumor necrosis factor-α(TNF-α), superoxide dismutase (SOD) activity, malondialdehyde (MDA) in perfusate, and the Wet-to-Dry lung weight ratios were measured. Results IR caused significant increases in the wet-to-dry lung weight ratios, the activity of lung MPO, the contents of MDA and TNF-α in perfusate, but decreasess in the SOD activity and neutrophils counts. Administration of isoflurane (both ISO1 and ISO2 groups) significantly protected against IR-induced injury the via inhibiting increases of MPO activity and contents of MDA and TNF-α in perfusate. Isoflurane significantly increased the SOD activity and neutrophils counts in perfusate. No difference was found between ISO1 and ISO2 groups. Conclusion Our results suggest that isoflurane protects the lungs against IR-induced injury in isolated rat lung model.