Subsequent maternal sleep deprivation aggravates cognitive impairment by modulating hippocampal neuroinflammatory responses and synaptic function in maternal isoflurane-exposed offspring mice.

INTRODUCTION: Pregnant women may need to undergo non-obstetric surgery under general anesthesia owing to medical needs, and pregnant women frequently experience sleep disturbances during late gestation. Preclinical studies demonstrated that maternal isoflurane exposure (MISO) or maternal sleep deprivation (MSD) contributed to cognitive impairments in offspring. Research studies in mice have revealed that SD can aggravate isoflurane-induced cognitive deficits. However, it remains unclear whether MSD aggravates MISO-induced cognitive deficits in offspring. The purpose of this research was to explore the combined effects of MSD and MISO on offspring cognitive function and the role of neuroinflammation and synaptic function in the process of MSD + MISO. METHODS: Pregnant mice were exposed to 1.4% isoflurane by inhalation for 4 h on gestational day (GD) 14. Dams were then subjected to SD for 6 h (12:00-18:00 h) during GD15-21. At 3 months of age, the offspring mice were subjected to the Morris water maze test to assess cognitive function. Then the levels of inflammatory and anti-inflammatory markers and synaptic function-related proteins were assessed using molecular biology methods. RESULTS: The results of this study demonstrated that MISO led to cognitive dysfunction, an effect that was aggravated by MSD. In addition, MSD exacerbated the maternal isoflurane inhalation, leading to an enhancement in the expression levels of interleukin (IL)-1ß, IL-6, and tumor necrosis factor-alpha and a reduction in the hippocampal levels of IL-10, synaptophysin, post-synaptic density-95, growth-associated protein-43, and brain-derived neurotrophic factor. CONCLUSION: Our findings revealed that MSD aggravated the cognitive deficits induced by MISO in male offspring mice, and these results were associated with neuroinflammation and alternations in synaptic function.

Activating astrocytic α2A adrenoceptors in hippocampus reduces glutamate toxicity to attenuate sepsis-associated encephalopathy in mice.

BACKGROUND: Glutamate metabolism disorder is an important mechanism of sepsis-associated encephalopathy (SAE). Astrocytes regulate glutamate metabolism. In septic mice, α2A adrenoceptor (α2A-AR) activation in the central nervous system provides neuroprotection. α2A-ARs are expressed abundantly in hippocampal astrocytes. This study was performed to determine whether hippocampal astrocytic α2A-AR activation confers neuroprotection against SAE and whether this protective effect is astrocyte specific and achieved by the modulation of glutamate metabolism. METHODS: Male C57BL/6 mice with and without α2A-AR knockdown were subjected to cecal ligation and puncture (CLP). They were treated with intrahippocampal guanfacine (an α2A-AR agonist) or intraperitoneal dexmedetomidine in the presence or absence of dihydrokainic acid [DHK; a glutamate transporter 1 (GLT-1) antagonist] and/or UCPH-101 [a glutamate/aspartate transporter (GLAST) antagonist]. Hippocampal tissue was collected for the measurement of astrocyte reactivity, GLT-1 and GLAST expression, and glutamate receptor subunit 2B (GluN2B) phosphorylation. In vivo real-time extracellular glutamate concentrations in the hippocampus were measured by ultra-performance liquid chromatography tandem mass spectrometry combined with microdialysis, and in vivo real-time hippocampal glutamatergic neuron excitability was assessed by calcium imaging. The mice were subjected to the Barnes maze and fear conditioning tests to assess their learning and memory. Golgi staining was performed to assess changes in the hippocampal synaptic structure. In vitro, primary astrocytes with and without α2A-AR knockdown were stimulated with lipopolysaccharide (LPS) and treated with guanfacine or dexmedetomidine in the presence or absence of 8-bromo- cyclic adenosine monophosphate (8-Br-cAMP, a cAMP analog). LPS-treated primary and BV2 microglia were also treated with guanfacine or dexmedetomidine. Astrocyte reactivity, PKA catalytic subunit, GLT-1 an GLAST expression were determined in primary astrocytes. Interleukin-1ß, interleukin-6 and tumor necrosis factor-alpha in the medium of microglia culture were measured. RESULTS: CLP induced synaptic injury, impaired neurocognitive function, increased astrocyte reactivity and reduced GLT-1 and GLAST expression in the hippocampus of mice. The extracellular glutamate concentration, phosphorylation of GluN2B at Tyr-1472 and glutamatergic neuron excitability in the hippocampus were increased in the hippocampus of septic mice. Intraperitoneal dexmedetomidine or intrahippocampal guanfacine administration attenuated these effects. Hippocampal astrocytes expressed abundant α2A-ARs; expression was also detected in neurons but not microglia. Specific knockdown of α2A-ARs in hippocampal astrocytes and simultaneous intrahippocampal DHK and UCPH-101 administration blocked the neuroprotective effects of dexmedetomidine and guanfacine. Intrahippocampal administration of DHK or UCPH-101 alone had no such effect. In vitro, guanfacine or dexmedetomidine inhibited astrocyte reactivity, reduced PKA catalytic subunit expression, and increased GLT-1 and GLAST expression in primary astrocytes but not in primary astrocytes that received α2A-AR knockdown or were treated with 8-Br-cAMP. Guanfacine or dexmedetomidine inhibited microglial reactivity in BV2 but not primary microglia. CONCLUSIONS: Our results suggest that neurocognitive protection against SAE after hippocampal α2A-AR activation is astrocyte specific. This protection may involve the inhibition of astrocyte reactivity and alleviation of glutamate neurotoxicity, thereby reducing synaptic injury. The cAMP/protein kinase A (PKA) signaling pathway is a potential cellular mechanism by which activating α2A-AR modulates astrocytic function.

Ropivacaine-loaded hydrogels for prolonged relief of chemotherapy-induced peripheral neuropathic pain and potentiated chemotherapy.

Chemotherapy can cause severe pain for patients, but there are currently no satisfactory methods of pain relief. Enhancing the efficacy of chemotherapy to reduce the side effects of high-dose chemotherapeutic drugs remains a major challenge. Moreover, the treatment of chemotherapy-induced peripheral neuropathic pain (CIPNP) is separate from chemotherapy in the clinical setting, causing inconvenience to cancer patients. In view of the many obstacles mentioned above, we developed a strategy to incorporate local anesthetic (LA) into a cisplatin-loaded PF127 hydrogel for painless potentiated chemotherapy. We found that multiple administrations of cisplatin-loaded PF127 hydrogels (PFC) evoked severe CIPNP, which correlated with increased pERK-positive neurons in the dorsal root ganglion (DRG). However, incorporating ropivacaine into the PFC relieved PFC-induced CIPNP for more than ten hours and decreased the number of pERK-positive neurons in the DRG. Moreover, incorporating ropivacaine into the PFC for chemotherapy is found to upregulate major histocompatibility complex class I (MHC-I) expression in tumor cells and promote the infiltration of cytotoxic T lymphocytes (CD8+ T cells) in tumors, thereby potentiating chemotherapy efficacy. This study proposes that LA can be used as an immunemodulator to enhance the effectiveness of chemotherapy, providing new ideas for painless cancer treatment.

The effects of hepatic ischemia/reperfusion injury on postoperative cognitive function in aged rats.

Introduction: Hepatic ischemia/reperfusion injury (I/R) is a significant source of morbidity and mortality after liver surgery. The aim of this study was to investigate the effect of hepatic I/R injury on the hippocampus in rats with postoperative cognitive dysfunction (POCD). Material and methods: Adult male Sprague-Dawley rats (n = 160, age: 20-25 months, weight: 300-350 g) received I/R surgery with ischemia for 20 min, 30 min, and 40 min in different groups. Behavior tests of the Morris water maze (MWM) test and the passive avoidance test were applied. Population spike (PS) of pyramidal cells, nuclear factor κB (NF-κB) and protein kinase γ (PKCγ) in the hippocampus were observed. Results: Within 10 days after surgery, in aged rats with varying impaired cognitive function, spike size and spike latency period were reduced, level of PKCγ was decreased and an increased level of NF-κB was observed in the I/R group, especially in the I/R group with ischemia for 40 min. The parameters showed no significant difference in rats in the I/R group compared with the sham group at the 18th day after surgery. Conclusions: Hepatic I/R injury has a negative impact on the postoperative cognitive function in aged rats, leading to hippocampus changes with PS abnormity and level changes of NF-κB, PKCγ. However, this cognitive deficit improved over time.

Dexmedetomidine alleviates hepatic ischaemia-reperfusion injury via the PI3K/AKT/Nrf2-NLRP3 pathway.

Hepatic ischaemia-reperfusion (I/R) injury constitutes a tough difficulty in liver surgery. Dexmedetomidine (Dex) plays a protective role in I/R injury. This study investigated protective mechanism of Dex in hepatic I/R injury. The human hepatocyte line L02 received hypoxia/reoxygenation (H/R) treatment to stimulate cell model of hepatic I/R. The levels of pyroptosis proteins and inflammatory factors were detected. Functional rescue experiments were performed to confirm the effects of miR-494 and JUND on hepatic I/R injury. The levels of JUND, PI3K/p-PI3K, AKT/p-AKT, Nrf2, and NLRP3 activation were detected. The rat model of hepatic I/R injury was established to confirm the effect of Dex in vivo. Dex reduced pyroptosis and inflammation in H/R cells. Dex increased miR-494 expression, and miR-494 targeted JUND. miR-494 inhibition or JUND upregulation reversed the protective effect of Dex. Dex repressed NLRP3 inflammasome by activating the PI3K/AKT/Nrf2 pathway. In vivo experiments confirmed the protective effect of Dex on hepatic I/R injury. Overall, Dex repressed NLRP3 inflammasome and alleviated hepatic I/R injury via the miR-494/JUND/PI3K/AKT/Nrf2 axis.

Nalbuphine and dexmedetomidine as adjuvants to ropivacaine in ultrasound-guided erector spinae plane block for video-assisted thoracoscopic lobectomy surgery: A randomized, double-blind, placebo-controlled trial.

BACKGROUND: Adjuvants to local anesthetics, such as nalbuphine and dexmedetomidine, can be used to improve the quality and duration of peripheral nerve block effects. Dexmedetomidine has been successfully used as an adjuvant of erector spinae plane block (ESPB) with ropivacaine in video-assisted thoracoscopic lobectomy surgeries (VATLS). This study aimed to compare the effects of nalbuphine and dexmedetomidine used as adjuvants to ropivacaine for ESPB in VATLS. METHODS: A total of 102 patients undergoing VATLS with ESPB were enrolled and randomized into 3 groups, each of which received a different adjuvant to ropivacaine. The visual analogue scale score, onset and duration of sensory block, use of patient-controlled analgesia (PCA), rate of rescue analgesia, duration of postoperative hospitalization, incidence of postoperative nausea and vomiting, and chronic pain were measured and observed. RESULTS: The visual analogue scale score, total PCA use, rate of rescue analgesia, and postoperative chronic pain in the ropivacaine with dexmedetomidine (RD), and ropivacaine with nalbuphine (RN) groups were lower than those in the ropivacaine (RC) group (P < .05). The duration of sensory block was longer and the first use of PCA occurred later in the RD and RN groups than they did in the RC group (P < .05). CONCLUSIONS: As an adjuvant to ropivacaine in ESPB, nalbuphine and dexmedetomidine are comparable in terms of the associated analgesia, sensory block duration, need for rescue analgesia, and incidence of chronic pain in patients after VATLS.