Extracellular vesicles ameliorates sleep deprivation induced anxiety-like behavior and cognitive impairment in mice.

The aim of this research was to explore the therapeutic capabilities of extracellular vesicles (EVs) derived from human umbilical cord mesenchymal stem cells (hUC-MSCs) that had been subjected to heat shock pretreatment, in treating psychiatric disorders induced by sleep deprivation in mice. The EVs were isolated and characterized, while western blotting was utilized to assess the expression of exosomal markers and heat shock protein 70 (HSP70). To evaluate the impact of EV treatment on anxiety-like behavior and cognitive impairment in sleep-deprived (SD) mice, the open field test, plus maze test, and Y-maze task were conducted. Heat shock pretreatment significantly increased the expression of HSP70 in EVs. Administration of EVs from heat shock-pretreated hUC-MSCs improved anxiety-like behavior and cognitive function in SD mice. Furthermore, EV treatment promoted synaptic protein expression, HSP70 expression and inhibited neuroinflammation in the hippocampus of SD mice. Western blotting analysis also revealed that EV treatment reduced the levels of TLR4 and p65 in the hippocampus. EVs from heat shock-pretreated hUC-MSCs have therapeutic potential for sleep deprivation-induced psychiatric disorders by regulating neuroinflammation and synaptic function in mice.

Liproxstatin-1 alleviates ferroptosis in sevoflurane anesthesia-induced cognitive deficits of aged mice: The role oxidative stress.

In this study, we aimed to validate the hypothesis that the interplay between sevoflurane, oxidative stress and ferroptosis is crucial for the pathogenesis of sevoflurane-induced cognitive impairment in aged individuals. The mice with sevoflurane-induced cognitive impairment were used to explore the effects of sevoflurane on oxidative stress, iron homeostasis, and cognitive function in aged mice. Iron content and oxidative stress markers were analyzed in hippocampal tissue homogenates using specific assays. Additionally, the levels of iron death-related markers (Fth1 and Gpx4) were assessed by real-time PCR and Western blotting. Morris Water Maze and novel object recognition (NOR) tests were conducted to evaluate cognitive function. Sevoflurane exposure in aged mice resulted in a significant increase in iron overloading in the hippocampus, followed by a subsequent stabilization. Oxidative stress levels were elevated in the hippocampal tissue of sevoflurane-exposed mice, and a significant correlation was observed between iron death and oxidative stress. Liproxstatin-1, a ferroptosis inhibitor, effectively ameliorated the decline in memory and learning abilities induced by sevoflurane anesthesia. Liproxstatin-1 treatment reduced iron overload and oxidative stress in the hippocampal tissue of aged mice. The expression of Fth1 and Gpx4, iron death-related markers, was downregulated following Liproxstatin-1 intervention. Our findings suggest that sevoflurane anesthesia disrupts iron homeostasis, leading to increased oxidative stress and cognitive impairment in aged mice. These results highlight the potential of targeting iron-mediated processes to mitigate sevoflurane-induced cognitive impairment in the aging population.

Hsp70 ameliorates sleep deprivation-induced anxiety-like behavior and cognitive impairment in mice.

BACKGROUND: Many neurobehavioral processes, including psychomotor, cognitive, and affection are negatively impacted by sleep deprivation (SD), which may be harmful to a person's physical and mental health. Heat shock proteins (Hsps) have been demonstrated to play a protective role in a number of neurodegenerative diseases and are essential for maintaining intracellular protein homeostasis, but their roles in SD remain elusive. METHODS: A mouse SD model was constructed using a modified multi-platform water environment method. The cognitive function was tested by novel object recognition test and Y-maze test, and anxiety-like behaviors were assessed by open field test (OFT). Protein expression was determined by Western blotting assay and ELISA assay. RESULTS: We found that SD could profoundly enhance anxiety levels and impair cognitive function in mice. SD also reduced the expression levels of p-cAMP-response element binding protein (CREB) and brain-derived neurotrophic factor (BDNF) and increased microglial activation and neuroinflammatory response in the hippocampus of mice. The intranasal injection of human recombinant Hsp70 protein could alleviate SD-induced anxiety and cognitive impairment, as well as restore pCREB and BDNF levels and reduce microglia-induced neuroinflammation in the hippocampus of SD mice. CONCLUSIONS: Hsp70 treatment might serve as a potential treatment for mitigating SD-related unfavorable symptoms.

Apigenin Alleviates Allodynia and Hyperalgesia in a Mouse Model of Chemotherapy-Induced Peripheral Neuropathy via Regulating Microglia Activation and Polarization.

BACKGROUND: Apigenin has been reported to exhibit anti-inflammatory and anti-oxidative activities. This study aimed to investigate the protective role of Apigenin on chemotherapy-induced peripheral neuropathy (CIPN). METHODS: CIPN mouse model was established using Paclitaxel treatment. Hot plate and tail prick latency tests were performed to examine the allodynia and hyperalgesia behaviors. Anti-inflammatory and anti-oxidative effects of Apigenin on CIPN were determined by enzyme-linked immunosorbent (ELISA) assay, Western blot, and qRT-PCR. Nuclear recruitment of nuclear factor erythroid 2-related factor 2 (NRF2) was analyzed to evaluate the underlying mechanisms of the protective effects of Apigenin. RESULTS: Apigenin significantly alleviated CIPN-induced nociceptive behaviors of CIPN mice. It also decreased the TNF-α and IL-1ß levels, suppressed oxidative stress and inflammation in the surgical spinal cord tissues. Mechanistically, Apigenin altered the pro-inflammatory and anti-inflammatory phenotypes ratio of microglia through promoting the nuclear recruitment of NRF2 and activating the NRF2/Antioxidant Response Element (ARE) signaling pathway. CONCLUSIONS: In summary, Apigenin relieves CIPN by regulating microglia activation and polarization, which provides a potential therapeutic strategy for CIPN treatment.

Energy intake restriction significantly improves POCD after internal fixation of tibial fractures in mice.

OBJECTIVE: To investigate the effect of energy intake restriction on postoperative cognitive dysfunction (POCD) after internal fixation of tibial fractures in mice. METHODS: Thirty mice were divided into model groups of internal fixation of tibial fractures with 0%, 20%, 30% and 40% energy intake restriction and sham operation group (n = 6). Novel object recognition task and elevated plus maze test were used to assess the ability of recognition memory and anxiety-related behavior before and one week after surgery. The blood samples were collected from mice on days 1, 3 and 7 after surgery, and the mice were euthanized on the 8th day after surgery. RT-PCR and Western blot were employed to detect the expression of AMPK-SIRT1 pathway-related genes and proteins in the hippocampus. ELISA was used to detect the levels of inflammatory factors in the peripheral blood of mice. Hematoxylin-eosin (H&E) staining and immunofluorescence (IF) staining were used to detect the proliferation, differentiation and injury of hippocampal cells. RESULTS: The results showed that 20% and 30% energy intake restriction significantly improved the POCD after internal fixation of tibial fractures in mice. Significantly, 30% energy intake restriction reduced the expression of AP-1, NF-κB, CD45, IBA-1, and inflammatory factors IL-1ß, IL-6, IL-8 and TNF-α, and increased the expression of AMPK and SIRT1 after the operation. H&E and IF staining showed that 30% energy intake restriction reduced postoperative hippocampal neuronal damage. CONCLUSION: Energy intake restriction can significantly improve POCD after internal fixation of tibial fractures in mice and may provide a new treatment paradigm for POCD patients.

Differential effects of remifentanil and sufentanil anesthesia on post-operative pain and cognitive functions.

This study aimed to investigate the differential effects of remifentanil and sufentanil anesthesia on post-operative pain and recovery of cognitive functions following surgical resection of human colon cancer orthotopically transplanted in rats. Human colon cancer cells HT-29 were used to establish a rat model of orthotopically transplanted colon cancer on to the cecal wall of rats. The transplanted tumors were then surgically removed after 5 weeks, using different doses of remifentanil and sufentanil anesthesia. At 24 h after the surgery, von Frey test, hot plate test and voluntary wheel running test were used to evaluated post-operative pain in the rats. Morris water maze test and fear conditioning test were employed to assess cognitive functions. Serum and colon tissues of the rats were also subjected to ELISA to measure levels of stress response factors, while colon tissues were analyzed by RT-PCR and Western blot to measure expression of inflammation response factors and NF-κB pathway-related factors. Sufentanil showed better effect in reducing post-operative pain, while remifentanil showed better recovery of cognitive functions after surgery. In addition, remifentanil resulted in less stress and inflammation response, caused milder activation of NF-κB pathway-related factors after surgery. Remifentanil and sufentanil exhibited differential effects on post-operative pain and recovery of cognitive function. Specifically, remifentanil caused lower stress and inflammation response, associated with dampened activation of the NF-κB pathway. Our results could provide theoretical basis for adopting appropriate analgesic strategy and agents according to the characteristics of individual patients.

Sarm1 is Essential for Anesthesia-Induced Neuroinflammation and Cognitive Impairment in Aged Mice.

Postoperative cognitive dysfunction (POCD) is a common phenomenon among elderly patients with unclear etiology. Sterile alpha and TIR motif-containing 1 (Sarm1) plays important roles in neuroinflammation and cognitive function, and activates Calpain which has been shown to promote POCD through TrkB cleavage. This study aims to test the hypothesis that Sarm1 is involved in POCD through regulating Calpain activity. Wild type and Sarm1 knock out mice were exposed to isoflurane. Mouse cognitive function was determined by Morris water maze test. Neuroinflammation was determined by Iba1 and GFAP protein levels and mRNA expression of proinflammatory cytokines. Calpain activation was determined by αII-spectrin degradation and TrkB cleavage. Mitogen-activated protein kinase (MAPK) signaling was determined by c-Jun N-terminal kinase and cJun phosphorylation both in vivo and in vitro by Western blot and immunofluorescence staining. We found that Sarm1 deletion suppressed isoflurane induced cognitive impairment and neuroinflammation. Deletion of Sarm1 inhibited isoflurane induced αII-spectrin degradation and TrkB cleavage, which indicates suppression of Calpain activation. Finally, deletion of Sarm1 suppressed isoflurane induced MAPK signaling both in vivo and in vitro. Our findings suggest that isoflurane anesthesia induced cognitive impairment is prevented by Sarm1 deletion in mice, making Sarm1 a potent therapeutic target for treating or preventing POCD.

The Anti-inflammatory Effect of Dexmedetomidine Administration on Patients Undergoing Intestinal Surgery: A Randomized Study.

BACKGROUND AND OBJECTIVE: Dexmedetomidine is a highly selective α2-adrenergic receptor agonist with sedative, analgesic, anti-sympathetic and stress-reducing effects. It has been widely used as an adjunct for general anesthesia of multiple surgeries. However, the relationship between the utilization of dexmedetomidine in intestinal surgery and the postoperative inflammatory response of patients remains unclear. METHODS: A randomized, controlled, single-blinded clinical trial was performed. Eighty-six patients assigned for intestinal surgery were recruited and were randomly divided into two groups (dexmedetomidine group, n = 40; control group, n = 40) [six participants were excluded due to multiple reasons, such as allergy and drug use history]. The clinical characteristics and physiological outcomes of participants who received different treatments (dexmedetomidine and 0.9% sodium chloride) were collected and analyzed. Blood samples of the two groups were collected before administration (T0), 10 min after pumping dexmedetomidine/saline solution (T1), immediately after the operation started (T2), 30 min after the operation started (T3), and immediately after the operation ended (T4). Enzyme-linked immunosorbent assay (ELISA) was performed to evaluate the proinflammatory factors. RESULTS: Intravenous injection of dexmedetomidine before intestinal surgery decreased a variety of circulating proinflammatory factors. Dexmedetomidine alleviated the stress response and promoted the recovery of cognitive ability among patients undergoing intestinal surgery. CONCLUSION: Dexmedetomidine administration in patients undergoing intestinal surgery inhibited the surgery-induced inflammatory reactions.

Inhibiting PDE7A Enhances the Protective Effects of Neural Stem Cells on Neurodegeneration and Memory Deficits in Sevoflurane-Exposed Mice.

Sevoflurane is widely used in general anesthesia, especially for children. However, prolonged exposure to sevoflurane is reported to be associated with adverse effects on the development of brain in infant monkey. Neural stem cells (NSCs), with potent proliferation, differentiation, and renewing ability, provide an encouraging tool for basic research and clinical therapies for neurodegenerative diseases. We aim to explore the functional effects of injecting NSCs with phosphodiesterase 7A (PDE7A) knock-down in infant mice exposed to sevoflurane. The effects of PDE7A in NSCs proliferation and differentiation were determined by cell counting kit-8 (CCK-8) assay and differentiation-related gene expression assay, respectively. The effects of NSCs with modified PDE7A on mice's long-term memory and learning ability were assessed by behavioral assays. Our data demonstrated that depleting PDE7A promoted, whereas forcing PDE7A suppressed the activation of cAMP/cAMP-response element binding protein (CREB) signaling as well as cell proliferation and neuronal differentiation of NSCs. Inhibition of PDE7A in NSCs exhibited profound improved effects on long-term memory and learning ability of mice exposed to sevoflurane. Our results for the first time show that knock-down of PDE7A improves the neurogenesis of NSCs in vitro and in vivo, and is beneficial for alleviating sevoflurane-induced brain damage in infant mice.

Ultrasound-guided stellate ganglion block alleviates stress responses and promotes recovery of gastrointestinal function in patients.

BACKGROUND: This study aimed to investigate the effect of preoperative ultrasound-guided stellate ganglion block (SGB) on the perioperative stress responses and gastrointestinal functions of patients undergoing laparoscopic colorectal cancer surgery. METHODS: A total of 60 colorectal cancer patients were enrolled in study and were randomized to be treated with or without SGB therapy. In the SGB group, patients were injected with 7 mL 0.5% ropivacaine in stellate ganglion under ultrasound guidance before anesthesia. Mean artery pressure (MAP), heart rate (HR), recovery of bowel sound and first exhaust, as well as levels of motilin, gastrin, norepinephrine, cortisol, interleukin-6 (IL-6) and C-reactive protein (CRP) were recorded at various time points. RESULTS: 26 patients in the SGB group and 27 patients in the control group were analyzed. No significant differences in MAP or HR were observed between the two groups before, during and after the surgery. SGB promoted recovery of gastrointestinal functions, as evidenced by earlier recovery of bowel sound and first exhaust, as well as increased motilin and gastrin levels. SGB also attenuated stress responses, as shown in reduced norepinephrine, cortisol, IL-6 and CRP levels. CONCLUSIONS: SGB promotes the recovery of gastrointestinal functions and reduces stress responses of colorectal patients undergoing laparoscopic colorectal cancer surgery.

Nalbuphine Exhibited a Better Adjuvant Than Dexmedetomidine in Supraclavicular Brachial Plexus Block in Youths.

OBJECTIVE: Nalbuphine and dexmedetomidine are both used as anesthesia adjuvants for brachial plexus block, but their efficacy and safety in younger patients are not clear. In this study, we aimed to compare the efficacy and side effects of these 2 drugs in young patients undergoing brachial plexus block. METHODS: We recruited 48 young patients aged 18 to 30 years requiring supraclavicular brachial plexus block. Subjects were randomly divided into 2 groups. Patients in group levobupivacaine+nalbuphine received 28 mL of 0.5% levobupivacaine and 10 mg of nalbuphine diluted in 2 mL 0.9% saline. Patients in group levobupivacaine+dexmedetomidine (LD) received 28 mL of 0.5% levobupivacaine and 0.75 µg/kg dexmedetomidine diluted in 2 mL 0.9% saline. Demographic information, types of fracture, onset time of motor and sensory blocks, duration of block, side effects, and analgesic use were recorded. RESULTS: We found that the 2 groups did not differ significantly in the demographic profile and fracture type. Compared with group LD, group LD had significantly shorter sensory and motor block onset time, longer block duration, less analgesic need, and less side effects. CONCLUSION: In summary, our study suggests that nalbuphine is a better anesthesia adjuvant for supraclavicular brachial plexus block in young patients.

Effects of Depth of Anesthesia Monitored by IoC on Patients Undergoing Laparoscopic Radical Resection of Colorectal Cancer.

Index of consciousness (IoC) consisting of IoC1 and IoC2, is a new analgesia monitoring indicator in anesthesia evaluation in the laparoscopic radical resection of colorectal cancer. Although the precise anesthetic dosage adjusted by IoC1 has been confirmed to enhance the recovery and reduce the complications of anesthesia, the most appropriate range of IoC2 during anesthesia remains unclear. To investigate the correlation between IoC2 and peri-operative indicators of patients during laparoscopic radical resection of colorectal cancer, the current randomized, controlled, and single-blinded clinical trial was performed. Participants were divided randomly into three groups with different anesthesia depth monitored by IoC2 during their laparoscopic radical resections. Primary outcomes included the dosage of remifentanil. Secondary outcomes included other physiological indexes and complications. The remifentanil dosage and the awakening time increased as IoC2 decreased. The incidences of hypotension and hypoxemia decreased with the elevated IoC2, but the risk of intra-operative awareness also increased. The impact caused by anesthesia to the immune system and health-related life quality of the patients descended with reduced anesthetic level. The IoC2 range of 35-45 could represent the most appropriate anesthetic depth during laparoscopic radical resection, which provides a new perspective for the clinical treatment of colon cancer.

PDE-7 Inhibitor BRL-50481 Reduces Neurodegeneration and Long-Term Memory Deficits in Mice Following Sevoflurane Exposure.

Sevoflurane, one of the most commonly used anesthetic agents, has been demonstrated to induce widespread neurodegeneration in the developing brain. We aimed to evaluate the protective effects of a PDE-7 inhibitor (BRL-50481) against the neurotoxic effects of sevoflurane on the developing nervous system. Spatial learning and memory in sevoflurane-treated mice were examined using the Morris water maze test, and neuroprotective effects of PDE-7 inhibitor (BRL-50481) against sevoflurane-induced impairments were evaluated. Our results showed that sevoflurane treatment markedly induced neurodegeneration and impaired long-term memory in neonatal mice. Notably, BRL-50481 coadministration could significantly attenuate sevoflurane-induced learning and memory defects, prevent deterioration of recognition memory, and protect against neuron apoptosis. Mechanistically, BRL-50481 administration suppressed sevoflurane-induced neurodegenerative disorders through restoring cAMP and activating cAMP/CREB signaling in the hippocampus. PDE7 inhibitor may be a potential therapeutic agent for sevoflurane-induced neurodegeneration and long-term memory deficits.

Long noncoding RNA LINC00630 promotes radio-resistance by regulating BEX1 gene methylation in colorectal cancer cells.

This study aimed to analyze the relation between long noncoding RNA (lncRNA) LINCE00630 and radio-resistance and elucidate the underlying mechanism. Relative expression of LINC00630, BEX1, and DNMT3B in colorectal cancer (CRC) cells and clinical samples was determined by real-time PCR. Prognosis in respect of LINC00630 expression was analyzed by Kaplan-Meier survival curve. LINC00630 and BEX1 were specifically silenced by shRNAs. Cell viability and growth were analyzed by MTT and clonogenic assays, respectively. Cell apoptosis was measure by both caspase-3 activity and flow cytometry. Association between EZH2 with LINC00630 and BEX1 promoter was determined by RNA immunoprecipitation and chromatin immunoprecipitation. BEX1 and DNMT3B proteins were quantified by Western blot. We demonstrated the elevated LINC00630 correlated with radio-resistance and poorer prognosis in CRC. Knockdown of LINC00630 significantly improved the sensitivity of CRC cells to irradiation. Mechanistically, LINC00630 in complex with EZH2 negatively regulated BEX1 through promoter DNA methylation. BEX1 silencing greatly restored the cell viability and suppressed cell apoptosis, which were elicited by LINC00630 deficiency in response to irradiation. Our data uncovered the contribution of elevated LINC00630 to radio-resistance in CRC, which was predominately mediated by epigenetically repressed BEX1.

miR-101 down-regulates mTOR expression and attenuates neuropathic pain in chronic constriction injury rat models.

We aimed to demonstrate the effects of microRNA (miR)-101 on neuropathic pain and explore the underlying mechanisms. Rat spinal microglia cells were isolated and inflammatory condition was stimulated by 24-h incubation with lipopolysaccharide (LPS). Rats were divided into 4 groups: sham, chronic constriction injury (CCI), CCI + miR-negative control (miR-NC) and CCI + miR-101 mimics. Paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) tests were conducted. The mRNA levels of key genes were determined by quantitative real-time polymerase chain reaction. Mammalian target of rapamycin (mTOR) protein level was detected by Western blot. Concentrations of interleukin (IL)-6, IL-1ß and tumor necrosis factor (TNF)-α were examined by ELISA. MiR-101 was downregulated and mTOR was upregulated in lumbar spinal dorsal horns from CCI rats. Targetscan and luciferase reporter assay confirmed that mTOR was direct target of miR101. MiR-101 mimics inhibited LPS-stimulated increase in the levels of IL-6, IL-1ß and TNF-α in primary microglial cells in vitro. In the rat CCI model, miR-101 mimics also suppressed CCI-induced decrease in PWT and PWL and inhibited CCI-induced increase in mRNA and protein levels of IL-6, IL-1ß and TNF-α. In addition, miR-101 downregulated mTOR mRNA and protein expressions in CCI rats. Besides, CCI operation resulted in miR-101 downregulation and mTOR mRNA upregulation in spinal microglia cells in a time-dependent manner. In conclusion, miR-101 had neuropathic pain-attenuating activity through targeting mTOR.

Long noncoding RNA LINC00342 promotes growth of infantile hemangioma by sponging miR-3619-5p from HDGF.

Infantile hemangiomas (IH) are a type of benign vascular neoplasm that may cause permanent scarring. Hemangioma-derived endothelial cells (HemECs) are commonly used as an in vitro model to study IH. Long noncoding RNA is a type of RNA transcript longer than 200 nucleotides that does not encode any protein. LINC00342 was discovered to regulate proliferation and apoptosis in nonsmall cell lung cancer. However, the role of LINC00342 in IH has never been reported before. Expressions of LINC00342 and miR-3619-5p were detected in proliferating versus normal skin tissues. Colony formation and Cell-Couting Kit 8 assays were carried out to study the effects on cell proliferation after knockdown and overexpression of LINC00342, respectively. Meanwhile caspase-3 activity and nucleosomal fragmentation assay were applied to detect cell apoptosis. Micro-RNA binding sites on LINC00342 and hepatoma-derived growth factor (HDGF) were predicted and confirmed via dual-luciferase reporter assay. Biotin RNA pulldown assay was used to verify the direct binding between RNA molecules. LINC00342 enhanced proliferation and inhibited apoptosis in HemECs. MiR-3619-5p targeted both LINC00342 and HDGF, where LINC00342 sponged miR-3619-5p and positively regulated HDGF. HDGF knockdown rescued the effects of LINC00342 on HemECs. The LINC00342-miR-3619-5p-HDGF signaling pathway could regulate cell proliferation and apoptosis in HemECs.NEW & NOTEWORTHY The role of LINC00342 in infantile hemangiomas has not yet been elucidated. This paper highlights the regulatory role of LINC00342 in cell proliferation and apoptosis in hemangioma-derived endothelial cells and the underlying molecular mechanisms. The findings would provide potential target for treatment of infantile hemangiomas.

Administration of Curcumin Alleviates Neuropathic Pain in a Rat Model of Brachial Plexus Avulsion.

BACKGROUND/AIMS: Brachial plexus avulsion (BPA) generally causes a chronic persistent pain that lacks efficacious treatment. Curcumin has been found to possess anti-inflammatory abilities. However, little is known about the mechanisms and effects of curcumin in an animal model of BPA. METHODS: Mechanical withdrawal thresholds (MWT) were examined by von Frey filaments. Cold allodynia was tested by the acetone spray test. The levels of tumor necrosis factor-α (TNF-α) and interleukin (IL)-6 in rat spinal cords were analyzed by the enzyme-linked immunosorbent assay, and the expression levels of c-Fos and nerve growth factor (NGF) were measured by Western blot. The expression level of glial fibrillary acidic protein (GFAP) was observed by immunofluorescence and Western blot. RESULTS: After curcumin treatment, the MWT showed a significant increase when compared to the BPA group on both hind paws. A remarkable decrease of paw-withdrawal response frequency was observed compared with the BPA group. In addition, curcumin treatment significantly decreased the levels of TNF-α and IL-6 in rat spinal cords that were exceedingly upregulated in the BPA group. The protein levels of c-Fos and NGF were decreased by treatment with curcumin compared with the corresponding protein levels in the BPA group. Besides, curcumin reduced the number of GFAP positive cells and GFAP expression. CONCLUSIONS: Our findings suggest that curcumin significantly extenuates the BPA-induced pain and inflammation by reducing the expression level of proinflammatory cytokines and pain-associated proteins and inhibiting the activity of astrocytes.

Hydromorphone protects CA1 neurons by activating mTOR pathway.

Hydromorphone has been shown to play protective effect in rat glial cell. However, whether hydromorphone plays important roles in ischemia-reperfusion (IR) injury and the involved signaling pathway remains unclear. In this study, we detected whether HM plays protective effect in IR injury mouse model, further followed by the mechanism exploration. Preconditioning with hydromorphone was performed for continuous 4 days at the doe of 2 mg/kg before IR injury induction. Intraperitoneal injection of rapamycin (Rapa) was administrated to examine the role of mTOR in IR injury. The mRNA expression level was detected by RT-PCR, and protein expression level was detected by western blot. Latency time and apoptosis of hippocampal CA1 neurons were detected 72 h after IR injury induction. Preconditioning with hydromorphone significantly increased Latency time, decreased apoptosis of hippocampal CA1 neurons and suppressed IR induced oxidative stress. Mechanically, preconditioning with hydromorphone increased Bcl-2 and p-mTOR expression levels and decreased Bax expression levels. Rapa administration reverses the role of hydromorphone in protecting hippocampal CA1 neurons from IR injury. Hydromorphone protect hippocampal CA1 neurons from IR injury via activating mTOR signaling pathway.