Propofol Pretreatment Research Articles

Protective Effects of Propofol Against Methamphetamine-induced Neurotoxicity.

Context:Methamphetamine (METH) is widely abused in worldwide. METH use could damage the dopaminergic system and induce neurotoxicity via oxidative stress and mitochondrial dysfunction. Propofol, a sedative-hypnotic agent, is known for its antioxidant properties. In this study, we used propofol for attenuating of METH-induced neurotoxicity in rats.Subjects and Methods:We used Wistar rats that the groups (six rats each group) were as follows: Control, METH (5 mg/kg IP), and propofol (5, 10 and 20 mg/kg, IP) was administered 30 min before METH. After 24 h, animals were killed, brain tissue was separated and the mitochondrial fraction was isolated, and oxidative stress markers were measured.Results:Our results showed that METH significantly increased oxidative stress markers such as lipid peroxidation, reactive oxygen species formation and glutathione oxidation in the brain, and isolated mitochondria. Propofol significantly inhibited METH-induced oxidative stress in the brain and isolated mitochondria. Mitochondrial function decreased dramatically after METH administration that propofol pretreatment significantly improved mitochondrial function. Mitochondrial swelling and catalase activity also increased after METH exposure but was significantly decreased with propofol pretreatment.Conclusions:These results suggest that propofol prevented METH-induced oxidative stress and mitochondrial dysfunction and subsequently METH-induced neurotoxicity. Therefore, the effectiveness of this antioxidant should be evaluated for the treatment of METH toxicity and neurodegenerative disease.

Propofol pretreatment attenuates remote kidney injury induced by orthotopic liver autotransplantation, which is correlated with the activation of Nrf2 in rats.

Nuclear factor erythroid 2‑related factor 2 (Nrf2) is a critical regulator of the cellular‑defense response in protection against oxidative injury. Several studies have demonstrated that propofol ameliorates ischemia/reperfusion injury in a number of organs. However, whether propofol exerts renal protection against liver transplantation via Nrf2 activation remains to be elucidated. The aim of the present study was to investigate the effects of orthotopic liver autotransplantation (OLAT) on renal Nrf2 expression and to determine whether propofol protects against kidney injury induced by OLAT via Nrf2 activation. A total of 24 male Sprague Dawley rats were randomly divided into four groups: sham surgery + normal saline (sham group); OLAT + normal saline (OLAT group); OLAT + propofol 50 mg/kg (L‑Prop group) and OLAT + propofol 100 mg/kg (H‑Prop group). Normal saline and propofol were administered for 3 consecutive days through an intraperitoneal injection prior to surgery. Kidney pathology, blood urea nitrogen (BUN), creatinine (Cr), superoxide anion (O2•‑), hydroxyl radical (·OH), maleic dialdehyde (MDA) and expression levels of Nrf2, Kelch‑like ECH‑associated protein 1 (Keap1), heme oxygenase‑1 (HO‑1) and NADP quinine oxidoreductase 1 (NQO1) were assessed 8 h after OLAT. It was demonstrated that OLAT induced remote kidney damage. Pretreatment with propofol significantly ameliorated renal pathology and abrogated the increase of the Cr and BUN concentrations, O2•‑ and ·OH activities, and MDA levels induced by OLAT. In the H‑Prop group, Keap1 expression in the cytoplasm was decreased and Nrf2 expression in the nucleus was upregulated, accompanied by an increase of HO‑1 and NQO1 expression. The present results suggest that propofol pretreatment exerted renal protection against OLAT, with the upregulation of nuclear Nrf2 expression as a potential mechanism.

Propofol pretreatment attenuates lipopolysaccharide-induced acute lung injury in rats by activating the phosphoinositide-3-kinase/Akt pathway

The aim of this study was to investigate the effect of propofol pretreatment on lipopolysaccharide (LPS)-induced acute lung injury (ALI) and the role of the phosphoinositide-3-kinase/protein kinase B (PI3K/Akt) pathway in this procedure. Survival was determined 48 h after LPS injection. At 1 h after LPS challenge, the lung wet- to dry-weight ratio was examined, and concentrations of protein, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in bronchoalveolar lavage fluid (BALF) were determined using the bicinchoninic acid method or ELISA. Lung injury was assayed via lung histological examination. PI3K and p-Akt expression levels in the lung tissue were determined by Western blotting. Propofol pretreatment prolonged survival, decreased the concentrations of protein, TNF-α, and IL-6 in BALF, attenuated ALI, and increased PI3K and p-Akt expression in the lung tissue of LPS-challenged rats, whereas treatment with wortmannin, a PI3K/Akt pathway specific inhibitor, blunted this effect. Our study indicates that propofol pretreatment attenuated LPS-induced ALI, partly by activation of the PI3K/Akt pathway.

Propofol attenuates LPS-induced tumor necrosis factor-α, interleukin-6 and nitric oxide expression in canine peripheral blood mononuclear cells possibly through down-regulation of nuclear factor (NF)-κB activation

Sepsis is a major cause of mortality in intensive care medicine. Propofol, an intravenous general anesthetic, has been suggested to have anti-inflammatory properties and able to prevent sepsis induced by Gram-positive and Gram-negative bacteria by down-regulating the gene expression of pro-inflammatory cytokines. However, propofol’s anti-inflammatory effects upon canine peripheral blood mononuclear cells (PBMCs) have not yet been clarified. Here, we isolate canine PBMCs and investigate the effects of propofol on the gene expressions of both lipopolysaccharide (LPS)-induced interleukin-6 (IL-6) and tumor necrosis factor (TNF)-α and upon the production of nitric oxide (NO). Through real-time quantitative PCR and the Griess reagent system, we found that non-cytotoxic levels of propofol significantly inhibited the release of NO and IL-6 and TNF-α gene expression in LPS-induced canine PBMCs. Western blotting revealed that LPS does significantly increase the expression of inducible NO synthase (iNOS) protein in canine PBMCs, while pretreatment with propofol significantly decreases the LPS-induced iNOS protein expression. Propofol, at concentration of 25 µM and 50 µM, also significantly inhibited the LPS-induced nuclear translocation of nuclear factor (NF)-κB p65 protein in canine PBMCs. This diminished TNF-α, IL-6 and iNOS expression, and NO production was in parallel to the respective decreased NF-κB p65 protein nuclear translocation in the LPS-activated canine PBMCs pretreated with 25 µM and 50 µM propofol. This suggests that non-cytotoxic levels of propofol pretreatment can down-regulate LPS-induced inflammatory responses in canine PBMCs, possibly by inhibiting the nuclear translocation of the NF-κB p65 protein.

Endoplasmic reticulum stress is involved in the neuroprotective effect of propofol.

Propofol is a common clinically used intravenous anaesthetic agent with antioxidative property. It has been thought to have neuroprotection in vitro and in vivo. However, the underlying mechanisms remain unclear. Endoplasmic reticulum (ER) stress plays an important role in regulating the signaling pathways concerning cell death and survival. Therefore, we wondered whether the neuroprotective effects of propofol are associated with its regulation on ER stress. In this study, we found that propofol up-regulated BiP and attenuated tunicamycin-induced neural cell death. Propofol pretreatment also inhibited tunicamycin-induced up-regulation of C/EBP homologous protein (CHOP). We also found that propofol or tunicamycin alone increased the levels of spliced XBP1 (XBP1s) and cleaved activating transcription factor 6 (ATF6), an active form of ATF6. However, pretreatment with propofol attenuated the levels of phosphorylated protein kinase receptor-like ER kinase, phosphorylated elF2α, ATF4, and caspase-3, but failed to affect the increase of cleaved ATF6 and XBP1s, induced by tunicamycin. Knockdown endogenous BiP with siRNA abolished the suppression of propofol on tunicamycin-mediated activation of CHOP and caspase-3. Meanwhile, knockdown BiP attenuated the protective effects of propofol on the neural cells exposed to tunicamycin. These data suggest that ER stress is involved in the neuroprotection of propofol via differentially regulating the unfolded protein response pathway, in which BiP plays an important role in initiating the adaptive ER stress and inhibiting the apoptotic ER stress.

Propofol pretreatment induced place preference and self-administration of the tiletamine-zolazepam combination: implication on drug of abuse substitution

Background: Propofol and the tiletamine-zolazepam combination are anesthetics with both sedative-hypnotic and hallucinogenic effects. In South Korea, propofol is controlled while the tiletamine-zolazepam combination is not. Thus, there is a possibility that this drug combination might be used as a substitute drug by propofol-abusers. Objective: In the present study we evaluated whether repeated pre-exposure to propofol predisposes to the use/abuse of the tiletamine-zolazepam combination. Methods: Rats (8–10 animals/group) were pre-treated with saline (control) or propofol at different dosages (10, 30, 60 mg/kg, i.p.), for 14 days, then conditioned place preference (CPP) and self-administration (SA) for the tiletamine-zolazepam combination were evaluated. Results: Rats pretreated with saline exhibited neither CPP nor SA for the tiletamine-zolazepam combination. On the other hand, rats pretreated with propofol, in all dosages, demonstrated significant CPP and SA for the tiletamine-zolazepam combination. Conclusion: These results suggest that tiletamine-zolazepam combinations might be used as a “substitute drug” by abusers of propofol. The careful use, dispensation, and monitoring of tiletamine-zolazepam combinations are advocated.

Electroconvulsive therapy pre-treatment with low dose propofol: Comparison with unmodified treatment

BackgroundWhilst electroconvulsive therapy (ECT) is routinely administered under anesthesia in developed nations, in many developing countries, ECT is still administered unmodified. This practice has attracted considerable scrutiny with calls to ban unmodified ECT. However, there are no affordable alternatives for many poor, acutely ill psychiatric patients. We evaluated whether administration of intravenous propofol 0.5 mg/kg for sedation by the ECT psychiatrist just prior to otherwise unmodified treatment improved acceptance of and reduced anxiety surrounding the treatment. MethodWe conducted an open label trial at The King George's Medical University in Lucknow, India. Forty-nine patients received propofol pre-treatment and 50 patients received unmodified treatment as usual. ResultsSocio-demographic profiles, diagnoses and clinical responses were comparable. Patients who received propofol experienced less anxiety monitored by the State-Trait Anxiety Inventory just prior to ECT (p < 0.001), and had a more favorable attitude towards treatment assessed by an established questionnaire (Freeman and Kendell, 1980). Propofol patients were less likely to experience post-ictal delirium monitored by the CAM-ICU (p = 0.015) and had fewer cognitive side-effects on the MMSE (p = 0.004). There were no adverse events associated with propofol administration. ConclusionWhilst unmodified ECT should never be used when modified ECT under anesthesia is available, we have found low dose propofol can be safely administered by the ECT psychiatrist to sedate patients pre-treatment who would otherwise receive completely unmodified treatment. The intervention was associated with reduced anxiety and a more positive attitude towards ECT, without compromising efficacy. A randomized double blind controlled study is necessary to confirm these benefits.

Propofol Activation of the Nrf2 Pathway Is Associated with Amelioration of Acute Lung Injury in a Rat Liver Transplantation Model

Objective. This study aimed to investigate whether propofol pretreatment can protect against liver transplantation-induced acute lung injury (ALI) and to explore whether Nrf2 pathway is involved in the protections provided by propofol pretreatment. Method. Adult male Sprague-Dawley rats were divided into five groups based on the random number table. Lung pathology was observed by optical microscopy. Lung water content was assessed by wet/dry ratio, and PaO2 was detected by blood gas analysis. The contents of H2O2, MDA, and SOD activity were determined by ELISA method, and the expression of HO-1, NQO1, Keap1, and nuclear Nrf2 was assayed by western blotting. Results. Compared with saline-treated model group, both propofol and N-acetylcysteine pretreatment can reduce the acute lung injury caused by orthotopic autologous liver transplantation (OALT), decrease the lung injury scores, lung water content, and H2O2 and MDA levels, and improve the arterial PaO2 and SOD activity. Furthermore, propofol (but not N-acetylcysteine) pretreatment especially in high dose inhibited the expression of Keap1 and induced translocation of Nrf2 into the nucleus to further upregulate the expression of HO-1 and NQO1 downstream. Conclusion. Pretreatment with propofol is associated with attenuation of OALT-induced ALI, and the Nrf2 pathway is involved in the antioxidative processes.

Comparison of the preventive effects of pretreatment of lidocaine with a tourniquet and a premixed injection of lidocaine on propofol-LCT/MCT injection pain

BackgroundLidocaine has been used widely to prevent propofol injection pain. Various methods of administration exist, such as lidocaine premixed with propofol or lidocaine pretreatment using a tourniquet, but it is unclear which method of lidocaine administration is more effective for the prevention of injection pain of propofol LCT/MCT. The purpose of this study was to compare pretreatment of lidocaine with a tourniquet and a premixed injection of lidocaine to prevent injection pain of propofol-LCT/MCT.MethodsPatients were randomly allocated into the pretreatment group (n = 117) or the premixed group (n = 117). The pretreatment group was pretreated with 2 ml of lidocaine 2%, held with a tourniquet, before propofol-LCT/MCT injection. The premixed group was injected with a premixed solution of propofol-LCT/MCT and 2 ml of lidocaine 2%. To evaluate the incidence and severity of pain, spontaneous verbal expressions of pain, movement of hand, frowning, and moaning were recorded, and the patients were asked to recall their pain with the visual analogue score (VAS) 30 minutes after awakening from anesthesia.ResultsOverall, injection pain occurred in 13.7% of the pretreatment group and 15.4% of the premixed group, without any statistical difference (P = 0.71). There was no difference in spontaneous verbal expressions of pain, movement of hand, frowning, and moaning between the two groups. The pain intensity (VAS) also showed no difference between the two groups (P = 0.49).ConclusionsPretreatment of lidocaine with a tourniquet showed no more benefit to prevent injection pain of propofol LCT/MCT compared to a premixed injection with lidocaine.

Hippocampal Neuron Protecting Effect of Propofol Against Hypoxia/Reoxygenation via Inducing Nerve Growth Factor

Propofol, an intravenous anesthetic agent, exhibits neuroprotective effects against cerebral ischemia–reperfusion injury. Here, we used a model of Hypoxia/Re-Oxygenation (H/R) injury to examine the hippocampal neuroprotective effect of propofol, and explored the role of Nerve Growth Factor (NGF) and NGF receptor TrkA in this action. Rat hippocampal neuron cells were subjected to H/R with different concentrations propofol, the viability and apoptosis of the cells were then determined by MTT assay and annexin V flow cytometry, respectively. Meanwhile, expression of NGF and TrkA were measured by RT-PCR and Western blot. The results showed that H/R significantly reduced viability and increased apoptosis of cultured hippocampal neuron cells, along with the significantly decreased expressions of NGF and TrkA. However, pretreatment of propofol recovered the expressions of NGF and the receptor TrkA, resulting in significantly decreased H/R-induced neurotoxicity. C-Jun N-terminal kinase (JNK) inhibitor suppressed the effect of propofol on the NGF expression, and the TrkA was decreased by PD98059, the Erk1/2 signal blocker. Administration of TrkA inhibitor altered the neuroprotective effect of propofol. These findings suggested the potential of propofol for protecting hippocampal neuron against H/R through at least partly, NGF/TrkA signaling pathway.

Effects of propofol on renal ischemia/reperfusion injury in rats

Renal ischemia/reperfusion injury (IRI) is a major cause of acute renal failure. The aim of this study was to investigate whether propofol pretreatment in a rat model protects kidney tissue against IRI. Thirty-two Wistar rats were equally divided into four groups: a sham-operated group, untreated renal IRI group, and low-dose (5 mg/kg) and high-dose (10 mg/kg) propofol-treated groups which were treated with propofol prior to the induction of IRI. The rats were subjected to renal ischemia by bilateral clamping of the pedicles for 50 min, followed by reperfusion. The low-dose and high-dose propofol treatment groups were pretreated via femoral vein injection with a propofol suspension prior to the induction of ischemia/reperfusion. The untreated IRI group showed significantly higher serum creatinine (SCr), blood urea nitrogen (BUN), interleukin 6 (IL-6), IL-8, tumor necrosis factor-α (TNF-α), and malondialdehyde (MDA) levels compared with the sham-operated rats. Superoxide dismutase (SOD) levels were significantly reduced following IRI; however, they significantly increased following propofol administration. Bone morphogenetic protein 2 (BMP2) levels were significantly increased in the propofol-treated groups compared with the untreated IRI group. These results suggest that propofol reduces renal oxidative injury and facilitates repair following IRI. Propofol may play a protective role by regulating BMP2 expression in renal IRI.

Rescue of cAMP Response Element‐Binding Protein Signaling Reversed Spatial Memory Retention Impairments Induced by Subanesthetic Dose of Propofol

The intravenous anesthetic propofol caused episodic memory impairments in human. We hypothesized propofol caused episodic-like spatial memory retention but not acquisition impairments in rats and rescuing cAMP response element-binding protein (CREB) signaling using selective type IV phosphodiesterase (PDEIV) inhibitor rolipram reversed these effects. Male Sprague-Dawley rats were randomized into four groups: control; propofol (25 mg/kg, intraperitoneal); rolipram; and rolipram + propofol (pretreatment of rolipram 25 min before propofol, 0.3 mg/kg, intraperitoneal). Sedation and motor coordination were evaluated 5, 15, and 25 min after propofol injection. Invisible Morris water maze (MWM) acquisition and probe test (memory retention) were performed 5 min and 24 h after propofol injection. Visible MWM training was simultaneously performed to resist nonspatial effects. Hippocampal CREB signaling was detected 5 min, 50 min, and 24 h after propofol administration. Rolipram did not change propofol-induced anesthetic/sedative states or impair motor skills. No difference was found on the latency to the platform during the visible MWM. Propofol impaired spatial memory retention but not acquisition. Rolipram reversed propofol-induced spatial memory impairments and suppression on cAMP levels, CaMKIIα and CREB phosphorylation, brain-derived neurotropic factor (BDNF) and Arc protein expression. Propofol caused spatial memory retention impairments but not acquisition inability possibly by inhibiting CREB signaling.

TLR4 signaling is involved in the protective effect of propofol in BV2 microglia against OGD/reoxygenation

Propofol exhibits neuroprotective effects against hypoxic-ischemic brain injury, but the underlying mechanisms are still not clear. Toll-like receptor 4 (TLR4) plays a considerable role in the induction of innate immune and inflammatory responses. The purposes of this study are to investigate the effect of propofol on the oxygen and glucose deprivation (OGD)/reoxygenation (OGD/R) BV2 microglia and to explore the role of TLR4/myeloid differentiation protein 88 (MyD88)/nuclear factor-kappa B (NF-κB) pathway in the neuroprotective effects of propofol. BV2 microglia were placed into an airtight chamber and in glucose-free medium for OGD/reoxygenation. Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide assay. TLR4 and its downstream signaling molecules, MyD88 and NF-κB expressions were detected by Western blotting. Level of tumor necrosis factor alpha (TNF-α) in culture medium was determined with enzyme-linked immunosorbent assay. BV2 microglia apoptosis was determined by flow cytometry. We found that pretreatment with propofol significantly alleviated the hypoxic injury in BV2 microglia. Propofol inhibited upregulation of TLR4, MyD88, and NF-κB expressions in BV2 microglia exposed to OGD/reoxygenation. Propofol pretreatment also significantly reduced the production of TNF-α and apoptosis in OGD/reoxygenation BV2 microglia. The results indicated that TLR4 and its downstream MyD88-dependent signaling pathway contributed to neuroprotection of propofol to microglia exposed to OGD/reoxygenation.

Propofol Increases Vascular Relaxation in Aging Rats Chronically Treated with the Angiotensin-Converting Enzyme Inhibitor Captopril

Both propofol use and advanced age are predictors of intraoperative hypotension. We previously demonstrated that propofol enhances vasodilation in mesenteric arteries from aged rats, partly due to increased nitric oxide (NO) bioavailability. Patients chronically treated with angiotensin-converting enzyme (ACE) inhibitors may exhibit refractory hypotension under general anesthesia. We hypothesized that propofol enhances NO-mediated vasodilation in arteries from aged rats chronically treated with ACE inhibitors. Sprague-Dawley rats aged 12 to 13 months were treated with or without captopril for 7 to 8 weeks, yielding a final age of 14 to 15 months at the time of experimentation. Before euthanasia, arterial blood pressures were obtained through carotid artery cannulation. Concentration-response curves to propofol (0.1-100 µM) or methacholine (MCh) (0.01-3 µM) were then assessed on isolated resistance mesenteric arteries (100-200 μm diameter) from both treatment (captopril) and control rats. MCh relaxation was also assessed after propofol pretreatment (1 and 10 µM). N(G)-nitro-l-arginine methyl ester (l-NAME) (100 µM) and meclofenamate (10 µM) were used to inhibit NO and prostaglandin synthesis, respectively. Concentration-response data were summarized as 50% of the maximum relaxation response or area under the curve. Mean arterial blood pressure in the captopril-treated rats was lower than in untreated rats (P = 0.049). When comparing relaxation in arteries from captopril-treated versus untreated rats, concentration-response curves revealed that captopril-treated rats display greater direct propofol relaxation (P = 0.018). MCh relaxation in the absence of propofol, however, was not different between captopril-treated and untreated rats (P = 0.80). Propofol pretreatment increased MCh relaxation in arteries from captopril-treated compared with untreated rats (P = 0.029 for 1 µM and P = 0.020 for 10 µM). Meclofenamate did not have an effect in this response (P = 0.22). l-NAME-dependent inhibition of MCh relaxation, however, was greater in arteries from control compared with captopril-treated rats (P = 0.0077). However, propofol increased the proportion of NO-dependent vasodilation to MCh similarly in both groups. This suggests that other vasodilatory pathways are involved in the differential response to MCh in the presence of propofol in captopril-treated rats. Our results show that mesenteric arterial relaxation in response to propofol, both by direct stimulation and through modulation of endothelium-dependent mechanisms, is, in part, NO-dependent. In captopril-treated rats, propofol further increased arterial relaxation through a non-NO-dependent vasodilating pathway (e.g., endothelium-derived hyperpolarizing factor), which may account for enhanced vasodilation during propofol exposure in patients treated with ACE inhibitors.

Propofol protects against high glucose-induced endothelial adhesion molecules expression in human umbilical vein endothelial cells

BackgroundHyperglycemia could induce oxidative stress, activate transcription factor nuclear factor kappa B (NF-κB), up-regulate expression of endothelial adhesion molecules, and lead to endothelial injury. Studies have indicated that propofol could attenuate oxidative stress and suppress NF-κB activation in some situations. In the present study, we examined whether and how propofol improved high glucose-induced up-regulation of endothelial adhesion molecules in human umbilical vein endothelial cells (HUVECs).MethodsProtein expression of endothelial adhesion molecules, NF-κB, inhibitory subunit of NF-κBα (IκBα), protein kinase Cβ2 (PKCβ2), and phosphorylation of PKCβ2 (Ser660) were measured by Western blot. NF-κB activity was measured by electrophoretic mobility shift assay. PKC activity was measured with SignaTECT PKC assay system. Superoxide anion (O2.-) accumulation was measured with the reduction of ferricytochrome c assay. Human peripheral mononuclear cells were prepared with Histopaque-1077 solution.ResultsHigh glucose induced the expression of endothelial selectin (E-selectin), intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), and increased mononuclear-endothelial adhesion. High glucose induced O2.- accumulation, PKCβ2 phosphorylation and PKC activation. Further, high glucose decreased IκBα expression in cytoplasm, increased the translocation of NF-κB from cytoplasm to nuclear, and induced NF-κB activation. Importantly, we found these high glucose-mediated effects were attenuated by propofol pretreatment. Moreover, CGP53353, a selective PKCβ2 inhibitor, decreased high glucose-induced NF-κB activation, adhesion molecules expression, and mononuclear-endothelial adhesion.ConclusionPropofol, via decreasing O2.- accumulation, down-regulating PKCβ2 Ser660 phosphorylation and PKC as well as NF-κB activity, attenuated high glucose-induced endothelial adhesion molecules expression and mononuclear-endothelial adhesion.

Antioxidant effects and mechanism of thiopental and propofol on the rabbit abdominal aortic endothelial dependent vasorelaxation against reactive oxygen species

Antioxidant effects and mechanism of thiopental and propofol on the rabbit abdominal aortic endothelial dependent vasorelaxation against reactive oxygen species

The protective effect of propofol pretreatment on glutamate injury of neonatal rat brain slices

To study the protective effect of propofol precondition against glutamate (Glu) neurotoxicity to neonatal rat cerebrocortical slices. Brain slices of Sprague-Dawley (SD) rats were cultured in vitro and observed the morphologic changes. Brain slices were randomly divided into three groups: blank control group, Glu injury group (1 mmol/L Glu for 0.5 hour), propofol precondition group (20 mg/L propofol for 24 hours), each n=12. Changes in pathological and ultra-structure of cells were observed using microscope. Lactate dehydrogenase (LDH) leakage rate was measured. Meanwhile, the expression of glial fibrillary acidic protein (GFAP) was detected by immunohistochemical technology, then the positive cell were counted. Cultured brain slices of cell were intact and survived well. Hematoxylin-eosin (HE) staining, electron microscopy and LDH test results showed that cerebral film neuron severely damage, gliosis, edema, LDH leakage rate in Glu injury group were significantly more severe compared with blank control group [(68.5±2.0)% vs. (16.0±2.5)%, P<0.01]. Reduce the brain slice of the propofol pretreatment group of neuronal cell jury, cell shape recovery significantly reduced LDH leakage rate compared with the Glu injury group [(38.5±2.4)% vs. (68.5±2.0)%, P<0.05]. Immunohistochemical detection of GFAP expression of Glu injury group glial cell body swelling, producing increase in the number of GFAP positive reaction strong, the number of positive cells compared with blank control group was significantly increased (50±5 cells/HP vs. 10±3 cells/HP, P<0.01). The recovery of propofol pretreatment group glial cell morphology, cell processes slender GFAP positive reaction decreased the number of positive cells compared with the Glu injury group was significantly decreased (30±4 cells/HP vs. 50±5 cells/HP, P<0.05). Propofol pretreatment has protective effect against Glu injured rat cerebrocortical slices.

Effects of pretreatment of lipid, midazolam and propofol on ropivacaine-induced convulsion and LD50 in rats

To assess the effects of lipid on ropivacaine-induced convulsion and LD50 in rats and compare with those of the traditional anticonvulsants midazolam and propofol. Protocol 1: A total of 120 SD rats (60 males, 60 females), weighing 200-300 g, were randomly assigned into 4 groups with equal males and females: lipid (L), midazolam (M) and propofol (P) and control (C). Rats were pretreated with 10 ml/kg lipid intravenously in group L, saline and 0.23 mg/kg midazolam (10 ml/kg in volume) sequentially in group M, saline and 4 mg/kg propofol (10 ml/kg in volume) in group P and saline 10 ml/kg in group C. Then ropivacaine 44 mg/kg (0.75%) was injected intraperitoneally into each rat. The convulsion rate in each group and the time of convulsion after ropivacaine injection were observed. Meanwhile, the plasma concentration of ropivacaine at the time of convulsion was measured. Protocol 2: Additional 100 male SD rats were used for the measurements of ropivacaine LD50 with different pretreatments including lipid, midazolam, propofol and saline through the up-and-down method. Rats were randomly assigned into 4 groups similarly as protocol 1. The doses of ropivacaine in each group were determined according to our pilot study and 6 dosage levels with the same interval ratio 8.5 was applied in each group. The doses of these pretreatment drugs and administration methods were similarly as protocol 1. The convulsion rate after 44 mg/kg ropivacaine ip injection was 43.3% in group C, 0% in group M, 13.3% in group P and 70% in group L. Lipid increased the convulsion rate significantly. The plasma concentration of ropivacaine at the time of convulsion was 1.65 ± 0.30 µg/kg in group C, 1.73 ± 0.14 µg/kg in group P and 3.45 ± 0.26 µg/kg in group L. The LD50 of ropivacaine in group C was 64.39 mg/kg, 88.40 mg/kg in group M and 90.20 mg/kg in group P and 55.45 mg/kg in group L. Midazolam and propofol not only decrease the convulsion rate of ropivacaine, but also increase its LD50. Lipid not only increases the convulsion rate of ropivacaine, but also decreases its LD50. The application of lipid for the prevention of local anesthetic toxicity has potential risks.

Neuroprotective effects of combined pretreatment with edaravone and propofol on neonatal rat cerebral cortical neurons with ischemia/reperfusion injury in vitro

To investigate the protective effect of combined pretreatment of edaravone and propofol on cerebral cortex with ischemia/reperfusion (I/R) injury and its therapeutic window. Sprague Dawley (SD) rat brain cortex cells harvested within 24 hours of birth were cultured in vitro for 7 days. The cells were then divided into blank control group, glutamate injury group, 24-hour drug precondition control group, and 24-, 2-, 0-hour drug precondition groups according to random number table. The nerve cells in each pretreatment group were cultured in medium containing 100 μmol/L of edaravone and 3 mg/L of propofol 24, 2, or 0 hour before glutamate damage (200 μmol/L for 0.5 hour). Nerve cell survival or damage was determined by methyl thiazolyl tetrazolium (MTT), lactate dehydrogenase (LDH) leakage rate, and nerve cell Na+-K+-ATPase activity. The oxidation and anti-oxidation ability of nerve cells was observed by determining superoxide dismutase (SOD) activity (xanthine oxidase), malondialdehyde (MDA) content (thiobarbituric acid). Nerve apoptosis was detected by flow cytometry. Compared with blank control group, in the glutamate injury group, nerve cell survival rate [(62.2±23.4)% vs. (90.5±14.8)%], the activity of SOD (U/ml: 6.864±2.872 vs. 29.569±3.684), Na+-K+-ATPase activity [U×mg(-1)×h(-1): 0.318±0.146 vs. 0.636±0.168] were significantly decreased, and rate of neuronal apoptosis [(9.4±0.7)% vs. (6.1±0.2)%], the content of MDA (nmol/ml: 0.515±0.101 vs. 0.294±0.105), LDH leakage rate [(41.2±1.6)% vs. (36.8±4.6)%] were significantly increased (P<0.05 or P<0.01). Compared with glutamate injury group, the cell survival rate and the activity of SOD and Na+-K+-ATPase were significantly increased in the drug pretreatment groups, and apoptosis rate, MDA content, and LDH leakage rate were significantly decreased with time-department, and effect in the 24-hour pretreatment group was most significant [survival rate of cell: (89.2±30.3)% vs. (62.2±23.4)%, SOD activity (U/ml): 17.780±4.514 vs. 6.864±2.872, Na+-K+-ATPase activity [U×mg(-1)×h(-1)]: 0.541±0.052 vs. 0.318±0.146, the rate of cell apoptosis: (6.7±0.4)% vs. (9.4±0.7)%, the content of MDA (nmol/ml): 0.319±0.101 vs. 0.515±0.101, LDH leakage rate: (37.2±1.4)% vs. (41.2±1.6)%, all P<0.01]. The synergistic protective effect of pretreatment with edaravone combined with propofol on neonatal rat brain cortex cells with I/R injury in vitro was evident; and 24-hour pretreatment is the best time window of protection for the cerebral neurons.

Propofol participates in gastric mucosal protection through inhibiting the toll-like receptor-4/nuclear factor kappa-B signaling pathway

Propofol has demonstrated protective effects against digestive injury. Toll-like receptor-4 (TLR4) is involved in gastric mucosal injury. However, it has not yet been clarified whether propofol protects gastric mucosa from ethanol-induced injury and whether the mechanism involved is related to TLR4 activation. Therefore, this prospective study was carried out to address the issue. Gastric mucosal injury was induced in mice by intragastric administration of ethanol. Propofol was given intraperitoneally 30 min before ethanol intragastric administration and, 1h later, gastric specimens were studied using hematoxylin--eosin staining, quantitative real-time RT-PCR, immunohistochemical staining and Western blot assays; serum specimens were studied using ELISA kits. Propofol at 25mg/kg significantly attenuated ethanol-induced gastric mucosal injury. In addition, propofol pretreatment significantly inhibited the upregulated expression of high-mobility group box-1 (HMGB1) protein, TLR4 and its downstream signaling molecules--myeloid differentiation factor 88 (MyD88) and nuclear factor kappa-B (NF-κB)--in gastric mucosa, while suppressing the increased release of tumor neurosis factor-α (TNF-α) and interleukin-1β (IL-1β) in serum. Furthermore, upregulation of the Bax/Bcl-2 ratio in gastric mucosa was clearly depressed by propofol. Propofol can inhibit HMGB1 expression and TLR4/MyD88/NF-κB-mediated inflammatory responses, and hamper apoptosis, which may contribute to its protective action against ethanol-induced gastric mucosal injury.