Role of c-Myc/chloride intracellular channel 4 pathway in lipopolysaccharide-induced neurodegenerative diseases.

LPS-induced neuronal apoptosis leads to neurodegenerative diseases (NDs). However, the mechanisms underlying NDs pathogenesis remains unclear. The apoptotic response to activation of the c-Myc/chloride intracellular channel (CLIC4) pathway is directed through a mitochondrial pathway. In this study, we aimed to explore the c-Myc/CLIC4 pathway in the progression of NDs induced by lipopolysaccharide (LPS). In an in vivo experiment, the results of HE staining, transmission electron microscopic, immunofluorescence microscopy of cleaved caspase-3 and Bax and the increasing expression of apoptotic pathway related proteins in mitochondria showed that LPS (10 mg/kg) administration damaged mitochondrial and induced hippocampal neuron apoptosis. The Western blot and RT-PCR indicated that LPS induced the activation of c-Myc/CLIC4 pathway. Furthermore, in an in vitro experiment, PC12 cells were exposed to LPS to induce cell injuries to mimic the model of NDs. To further confirm the role of the c-Myc/CLIC4 pathway in LPS-induced neuronal apoptosis, the gene knockout of c-Myc and CLIC4 were performed by CRISPR/Cas9. The results of the flow cytometry assay and Annexin V-FITC/PI showed that knocking out c-Myc and CLIC4 significantly reduced cell apoptosis. The results of Western blot and dual immunofluorescence with Cyt c and TOM20 showed that knocking out c-Myc and CLIC4 significantly reduced the expression of mitochondrial apoptosis-related proteins. Our data confirmed that LPS-induced apoptosis is regulated by the activation of c-Myc/CLIC4 pathway. These results support further research mechanisms underlying neurodegenerative diseases and can provide effective pharmacodynamic targets for the clinical development of therapeutic drugs for neurodegenerative diseases.

Partial (two-thirds) nephrectomy in pigs: A comparison of three surgical approaches.

Partial (2/3) nephrectomy can be performed via the laparoscopic, retroperitoneal, and transperitoneal approach. Outcomes of the three approaches were compared in this study. 2/3 nephrectomy were performed in 21 healthy Bama miniature pigs (mean bodyweight 20.59±2.78kg). Pigs were divided into three groups: those that underwent 2/3 nephrectomy via laparoscopy (LN group, n=7), the retroperitoneal approach (RN group, n=7), or the transperitoneal approach (TN group, n=7). We monitored pre- and postoperative physiologic parameters, blood cell count, and stress and renal function biomarkers. Differences among groups were analyzed. 2/3 nephrectomy was successfully performed in all pigs without any complications. Mean surgical time in the LN group (60.71±7.34min) and the TN group (58.57±4.72min) was significantly longer than that in the RN group (41.14±5.33min). Warm ischemia in the LN group (38±7.57min) was significantly longer than that in the TN group (28.86±4.53min), which was significantly longer than that in the RN group (17.86±2.34min). The postoperative serum concentration of C-reactive protein in the TN group was significantly higher than that in the LN group (p<0.05). So retroperitoneal approach was best choice in case of bilateral renal lesion resulted in shortest ischemia time, and laparoscopic partial nephrectomy should be the primary choice in majority situations resulted in less body stress, smaller surgical incisions and less blood loss.

Effect of melatonin on attenuating the isoflurane-induced oxidative damage is related to PKCα/Nrf2 signaling pathway in developing rats.

Isoflurane, an inhalational anesthesia, has frequently been used in pediatric anesthesia. However, research indicates that isoflurane can induce oxidative stress and affect neural and cognitive development. Melatonin, an endogenous hormone that exhibits antioxidant functions, can play a neuroprotective role by activating the PKCα/Nrf2 signaling pathway in response to oxidative stress. This study aims to determine whether the effect of melatonin on isoflurane-induced oxidative stress is related to activation of the PKCα/Nrf2 signaling pathway. Rat pups at postnatal day 7 were treated with control or 1.5% isoflurane for 4 h after pretreatment for 15 min with either melatonin (10 mg/kg i.p.) or 1% ethanol. The hematoxylin and eosin staining and transmission electron microscopic examination were used for observation of histopathology. The oxidative stress-related indicators were detected by using assay kits. The western blotting, immunohistochemistry and immunofluorescence were used to detect the activation of PKCα/Nrf2 signaling pathway. Results showed that isoflurane induced nerve damage in the hippocampus, and melatonin could reduce this injury. Oxidative stress-related indicators suggested that isoflurane can significantly increase reactive oxygen species and malondialdehyde levels, and decrease superoxide dismutase and glutathione activity compared with the control group, whereas melatonin ameliorated these indices. Expression of proteins associated with the PKCα/Nrf2 signaling pathway indicated that the neuroprotective effect of melatonin is related to activation of the PKCα/Nrf2 signaling pathway. These results suggest that the attenuating effect of melatonin on isoflurane-induced oxidative stress is related to activation of the PKCα/Nrf2 signaling pathway. These findings promote further research into underlying mechanisms and effective treatments to attenuate anesthesia neurotoxicity.

Inductive effect of Zoletil on cystathionine ß-synthase expression in the rat brain.

Zoletil is an anesthetic and immobilizing drug that has been used in the veterinary field for over 50 years; however, the effect of Zoletil, or its constituents, on brain cystathionine ß-synthase (CBS) remains unknown. Here, we aimed to determine the effect of Zoletil on rat brain CBS by administering a single intraperitoneal injection of the drug and examining hydrogen sulfide (H2S) and CBS levels in the cerebral cortex, hippocampus, and thalamus following three distinct behavioral phenotypes associated with the sedation procedure (e.g., loss of the righting reflex, return of the righting reflex, and return of walking). Zoletil administration resulted in significant decreases of endogenous H2S in the cerebral cortex, hippocampus, and thalamus, and H2S was observed to increase in these brain regions when rats recovered from the anesthesia. Quantitative real-time polymerase chain reaction, western blot, and immunohistochemistry revealed that CBS expression in the cerebral cortex and hippocampus exhibited the same trend as endogenous H2S following Zoletil administration. In summary, our results demonstrated that Zoletil induced the expression of CBS which could exert region-specific regulation of H2S in the cerebral cortex and hippocampus.

Effects of tiletamine on the adenosine monophosphate-activated protein kinase signaling pathway in the rat central nervous system.

OBJECTIVE: The dissociative anesthetic tiletamine, which acts on the central nervous system (CNS), is widely used in veterinary medicine and animal experiments. Recent studies indicate that adenosine 5'-monophosphate activated protein kinase (AMPK) plays a key role in the analgesic action of tiletamine. In the present study, the effects of tiletamine on the AMPK signaling pathway in rats were investigated. METHODS: Sprague-Dawley rats were injected intraperitoneally with tiletamine and executed at 10, 20, 40 and 60min post injection. The cerebral cortex, hippocampus, thalamus, cerebellum and brainstem were immediately taken out to evaluate the mRNA and protein phosphorylation levels of liver kinase B1 (LKB1), AMPKα and eIF4E-binding protein 1 (4EBP1) using quantitative real-time polymerase chain reaction and western blot analysis. RESULTS: Tiletamine increased AMPK mRNA expression in the rat brain (P<0.01). Increased mRNA expression of AMPK was accompanied by an increase in phosphorylation of LKB1, resulting in significant decreases in the phosphorylation levels of 4EBP1 in the corresponding brain regions (P<0.01). CONCLUSION: In summary, the findings indicate that tiletamine regulates the mRNA expression and protein phosphorylation levels of LKB1, AMPK and 4EBP1 in the CNS, suggesting that the analgesic effect of the anesthetic is mediated, at least in part, by the AMPK signaling pathway.

Behavioral and cardiopulmonary effects of dexmedetomidine-midazolam and dexmedetomidine-midazolam-butorphanol in the silver fox (Vulpes vulpes).

OBJECTIVE: To evaluate the behavior and some cardiopulmonary variables of dexmedetomidine-midazolam or dexmedetomidine-midazolam-butor-phanol in the silver fox (Vulpes vulpes). STUDY DESIGN: Blinded, randomized design. ANIMALS: Sixteen adult silver foxes, aged 7-9 months, weighting 6.0-9.2 kg. METHODS: Animals were randomly assigned to dexmedetomidine (50 µg kg-1) and midazolam (0.45 mg kg-1) (group DM) or to dexmedetomidine (30 µg kg-1), midazolam (0.45 mg kg-1) and butorphanol (0.25 mg kg-1) (group DMB), administered intramuscularly. Pulse rate (PR), respiratory rate (fR), noninvasive arterial pressures, oxygen saturation (SpO2), rectal temperature (T) and behavioral scores (posture, sedation, antinociception, jaw relaxation and auditory response) were measured at 5, 10, 20, 30, 40, 50 and 60 minutes after injection. Time from drug injection to recumbency with no response to stimuli (IT) and time from administration of atipamezole (0.2 mg kg-1) to standing with coordination (RT) were recorded. The occurrences of adverse events were recorded. Data were analyzed by two-tailed unpaired t-tests and Bonferroni post hoc tests. Significant differences were accepted at p<0.05. RESULTS: There were no statistically significant differences between the groups for IT or RT. Arterial pressures were higher in DMB at each time point except at 5 minutes. PR was lower in DM at each time point except at 10 and 60 minutes. No significant difference was found between the groups for fR, SpO2 and T. The behavioral scores were significantly lower (lower quality immobilization) in DMB at 5,10 and 60 minutes. CONCLUSIONS AND CLINICAL RELEVANCE: IT and RT were not different between the groups. Both protocols provided immobilization for 30-40 minutes with excellent muscle relaxation and analgesia adequate for clinical examinations and some simple surgical procedures.

Xylazine Activates Adenosine Monophosphate-Activated Protein Kinase Pathway in the Central Nervous System of Rats.

Xylazine is a potent analgesic extensively used in veterinary and animal experimentation. Evidence exists that the analgesic effect can be inhibited using adenosine 5'-monophosphate activated protein kinase (AMPK) inhibitors. Considering this idea, the aim of this study was to investigate whether the AMPK signaling pathway is involved in the central analgesic mechanism of xylazine in the rat. Xylazine was administrated via the intraperitoneal route. Sprague-Dawley rats were sacrificed and the cerebral cortex, cerebellum, hippocampus, thalamus and brainstem were collected for determination of liver kinase B1 (LKB1) and AMPKα mRNA expression using quantitative real-time polymerase chain reaction (qPCR), and phosphorylated LKB1 and AMPKα levels using western blot. The results of our study showed that compared with the control group, xylazine induced significant increases in AMPK activity in the cerebral cortex, hippocampus, thalamus and cerebellum after rats received xylazine (P < 0.01). Increased AMPK activities were accompanied with increased phosphorylation levels of LKB1 in corresponding regions of rats. The protein levels of phosphorylated LKB1 and AMPKα in these regions returned or tended to return to control group levels. However, in the brainstem, phosphorylated LKB1 and AMPKα protein levels were decreased by xylazine compared with the control (P < 0.05). In conclusion, our data indicates that xylazine alters the activities of LKB1 and AMPK in the central nervous system of rats, which suggests that xylazine affects the regulatory signaling pathway of the analgesic mechanism in the rat brain.

Comparison of the effects of propofol and emulsified isoflurane alone or combined with dexmedetomidine on induction of anesthesia in dogs.

OBJECTIVE: To compare the respective effects of propofol and emulsified isoflurane administered alone and in combination with dexmedetomidine on the quality of induction of anesthesia, physiological variables and recovery in dogs. STUDY DESIGN: Prospective, randomized, experimental trial. ANIMALS: Thirty-six adult mixed-breed dogs. METHODS: Animals were randomly assigned to one of four induction protocols: propofol alone (group P); emulsified isoflurane alone (group EI); both propofol and dexmedetomidine (group PD), or both emulsified isoflurane and dexmedetomidine (group EID). Pulse rate (PR), respiratory rate (fR ), non-invasive arterial blood pressure and arterial blood gases were measured at baseline, before induction, immediately after intubation (time 0), and at 5 minute intervals until the dog began to swallow and the trachea was extubated. The quality of induction and recovery, and degree of ataxia were scored by a single investigator unaware of group assignment. The durations of anesthesia and recovery, and the incidence of adverse events were recorded. RESULTS: There were no clinically significant differences among the groups in induction quality. Systolic arterial pressure was lower in EID compared with P at 5 minutes. PR and fR were lower in PD and EID compared with P after induction. The PaCO2 at 5 minutes was higher than at baseline in group P. Ataxia score was lower in EID than in P. Time from induction to extubation and time from extubation to sternal recumbency were lower in EID compared with PD. CONCLUSIONS AND CLINICAL RELEVANCE: There were no clinically significant differences among the groups in induction quality. In PD and EID, but not in P, PR and fR were decreased after induction. The EID combination resulted in smooth and rapid induction and recovery and thus may be useful clinically for induction of anesthesia.

Antagonistic effect of atipamezole, flumazenil and naloxone following anaesthesia with xylazine, tramadol and tiletamine/zolazepam combinations in pigs.

OBJECTIVE: To evaluate the antagonistic effects of atipamezole (ATI), flumazenil (FLU) and naloxone (NAL) alone and in various combinations following administration of tiletamine-zolazepam-xylazine-tramadol. STUDY DESIGN: Prospective, experimental, randomized cross-over study. ANIMALS: Eight Chinese miniature pigs (three females and five males) mean age 8 (range 7-10) months and bodyweight 57.5 (52.4-62.1) kg. METHODS: All animals were anaesthetized with tiletamine/zolazepam (3.0 mg kg(-1)), xylazine (1.2 mg kg(-1)) and tramadol (1.6 mg kg(-1)) given intramuscularly (IM). Thirty minutes later, one of eight treatments was administered IM: saline control, ATI (0.12 mg kg(-1)), FLU (0.1 mg kg(-1)), NAL (0.03 mg kg(-1)), ATI-FLU, FLU-NAL, ATI-NAL or ATI-FLU-NAL. After injection of antagonists the following times were recorded: to recovery of the palpebral, pedal and tail clamp reflexes, to head movement, sternal recumbency, standing and walking. Posture, sedation, analgesia, jaw relaxation and auditory response were scored at set times until 120 minutes after injection of antagonists. Heart rates, respiratory rates and rectal temperature were measured at those times. Data were analyzed by anova for repeated measures, followed by the Tukey's test to compare differences between means, or by Kruskal-Wallis test as appropriate. RESULTS: FLU, NAL alone, or FLU-NAL did not effectively antagonize anaesthesia induced by tiletamine/zolazepam-xylazine-tramadol. ATI, ATI-FLU, ATI-NAL and ATI-FLU-NAL produced an immediate and effective recovery from anaesthesia. The combination of ATI-FLU-NAL was the most effective combination in antagonizing the anaesthetic effect. Adverse effects such as tachycardia, tachypnoea, excitement and muscle tremors were not observed during this study. CONCLUSION AND CLINICAL RELEVANCE: ATI-FLU-NAL is the most effective combination for antagonizing tiletamine/zolazepam-xylazine-tramadol anaesthesia in pigs. However, ATI alone or in various combinations also provides effective antagonism.

Laparoscopy for percutaneous tube cystostomy in dogs.

OBJECTIVE: To describe a laparoscopic technique for percutaneous tube cystostomy in dogs. DESIGN: Prospective cohort study. ANIMALS: 8 healthy mixed-breed dogs. PROCEDURES: A laparoscope portal and 2 instrumental portals were created in the abdomen of anesthetized dogs that were in dorsal recumbency. Intracorporeal suturing was performed to place 2 simple interrupted sutures between the ventral body wall and urinary bladder. A purse-string suture was placed in the urinary bladder wall approximately 1 cm cranial to the 2 simple interrupted sutures. A stab incision was made into the urinary bladder in the middle of the purse-string suture; an 8F Foley catheter was inserted through the stab incision and into the urinary bladder. Two other sutures were placed between the ventral body wall and bladder 1 cm cranial to the Foley catheter to create a cystopexy. The Foley catheter was secured to the skin with a finger-trap suture and was attached to a closed urine collection bag. All dogs underwent follow-up laparoscopy 1 month later. RESULTS: Median time for laparoscopic percutaneous tube cystostomy was 85 minutes (range, 72 to 103 minutes); there were no major intraoperative or postoperative complications. On follow-up laparoscopy, focal fibrous adhesions between the ventral body wall and bladder were observed in all dogs and omentum attached to the cystopexy site was observed in 2 dogs. CONCLUSIONS AND CLINICAL RELEVANCE: In this study, a laparoscopic percutaneous tube cystostomy was accomplished in healthy dogs by use of a 3-portal technique and appeared to be an effective and safe procedure.