Objective To evaluate the effects of different doses of propofol or isoflurane on the cochlear blood flow (CBF) in guinea pigs.Methods Fifty-four adult male guinea pigs,aged 3 months,weighing 400-500 g,were randomly divided into 6 groups (n =9 each).In P1,P2 and P3 groups,propofol was infused for 115 min at 10,20 and 40 mg· kg-1 · h-1,respectively,after a loading dose of 5 mg/kg was injected over 5 min.In S1,S2 and S3 groups,isoflurane was inhaled for 120 min with end-tidal concentrations of 1％,2％ and 3 ％,respectively.Mean arterial pressure and CBF were recorded before administration (baseline,T1) and during the period of drug administration.Distortion product otoacoustic emission (DPOAE) was measured at T1,at the end of administration (T2) and 1 h after administration (T3).Five animals in each group were sacrificed and organs of Corti were harvested for observation of morphology of out hair cells by scanning electron microscopy.Results Propofol decreased MAP and increased CBF and DPOAE amplitude in a dose-dependent manner.Isoflurane decreased MAP and CBF in a dose-dependent manner.1％ isoflurane increased DPOAE amplitude,however,2％ and 3％ isoflurane decreased it and caused damage to out hair cells.Conclusion Propofol induces an increase in CBF in guinea pigs,while high concentration of isoflurane induces a decrease in CBF.Isoflurane inhibits CBF autoregulation,which makes CBF more sensitive to perfusion pressure,thus causing damage to hearing function.This is the reason why high concentration of isoflurane induces a decrease in CBF.

OBJECTIVETo investigate the protective effect of low-dose ketamine against intestinal ischemia reperfusion injury following pneumoperitoneum with carbon dioxide in rats.

METHODSThirty healthy male adult SD rats (body weight 280-320 g) were randomized into sham-operated group, model group and ketamine group and subjected to pneumoperitoneum for 120 min with carbon dioxide (not in sham-operated group). The rats in ketamine group received an intraperitoneal injection of 10 mg/kg ketamine 10 min before pneumoperitoneum, and those in the other two groups received saline injection. Fifteen minutes after pneumoperitoneum or sham operation, the small intestines were sampled to detect the content of malondialdehyde (MDA) and fore pathological testing. ELISA was used to detect the serum levels of I-FABP, TNF-α IL-6 and IL-8.

RESULTSPneumoperitoneum caused a significant increase in intestinal MDA content (P<0.05), which was lowered by ketamine pretreatment (P<0.05). Serum I-FABP, TNF-α, IL-6 and IL-8 levels all significantly increased following pneumoperitoneum (P<0.05) and were obviously lowered by ketamine pretreatment (P<0.05). Pneumoperitoneum also caused obvious pathologies in intestinal mucosa, which were ameliorated by ketamine pretreatment.

CONCLUSIONLow-dose ketamine preconditioning can reduce the inflammatory reaction and lessen oxidative damage in the intestinal mucosa following pneumoperitoneum in rats.

Animals ; Carbon Dioxide ; Dose-Response Relationship, Drug ; Fatty Acid-Binding Proteins ; blood ; Interleukin-6 ; blood ; Interleukin-8 ; blood ; Intestine, Small ; blood supply ; metabolism ; pathology ; Ketamine ; administration & dosage ; therapeutic use ; Male ; Malondialdehyde ; metabolism ; Pneumoperitoneum ; chemically induced ; complications ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Reperfusion Injury ; blood ; etiology ; metabolism ; pathology ; prevention & control ; Tumor Necrosis Factor-alpha ; blood