Dexmedetomidine alleviates lipopolysaccharide-induced lung injury in Wistar rats

Utilizing Nanoparticles of Hesperidin Loaded on Layered Double Hydroxide to Reduce Hepatotoxicity Caused by Paracetamol in Rats: Controlling of Biotransformation, Oxidative Stress, Inflammation, and Apoptosis

Background/Objectives: The most used antipyretic and pain relief treatment is paracetamol (acetaminophen), also known as N-acetyl-para-aminophenol (APAP). However, it is considered potentially hazardous if consumed repeatedly in large doses or over prolonged periods. This investigation explores the effectiveness of hesperidin (Hesp) and Hesp loaded on layered double hydroxide nanoparticles (Hesp-NPs) in inhibiting the progression of acute hepatotoxicity in rats induced by APAP. Methods: LDH-Hesp-NPs were prepared and characterized. Male Wistar rats were orally treated with Hesp and Hesp-NPs at the same adjusted dose (100 mg/kg) every other day for six weeks. After 2 h of the first doses of Hesp and Hesp-NPs, the rats received one oral dose of APAP (750 mg/kg). Results: Administering of Hesp and Hesp-NPs to APAP-treated rats significantly reduced oxidant parameter (malondialdehyde) and serum enzymes (ALT, AST, LDH, and ALP) associated with liver function. Antioxidant markers in the liver, such as catalase and glutathione, also increased notably. Moreover, Hesp and Hesp-NPs enhanced the mRNA expression of liver UGT1A6, IL-10, and HO-1. Conversely, the mRNA expressions of liver CYP1A1, KEAP1, TGF-β, P53, and BAX decreased. These improvements in biochemical and molecular markers were corroborated by liver histopathology. Conclusions: Hesp and Hesp-NPs protect significantly against APAP-induced hepatotoxicity in male Wistar rats. Hesp-NPs treatment was more potent. The protective effects may be mediated via modulation of APAP biotransformation, oxidative stress, inflammation and apoptosis.

Pyroptosis in Diabetic Peripheral Neuropathy and its Therapeutic Regulation

Pyroptosis is a pro-inflammatory form of cell death resulting from the activation of gasdermins (GSDMs) pore-forming proteins and the release of several pro-inflammatory factors. However, inflammasomes are the intracellular protein complexes that cleave gasdermin D (GSDMD), leading to the formation of robust cell membrane pores and the initiation of pyroptosis. Inflammasome activation and gasdermin-mediated membrane pore formation are the important intrinsic processes in the classical pyroptotic signaling pathway. Overactivation of the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome triggers pyroptosis and amplifies inflammation. Current evidence suggests that the overactivation of inflammasomes and pyroptosis may further induce the progression of cancers, nerve injury, inflammatory disorders and metabolic dysfunctions. Current evidence also indicates that pyroptosis-dependent cell death accelerates the progression of diabetes and its frequent consequences including diabetic peripheral neuropathy (DPN). Pyroptosis-mediated inflammatory reaction further exacerbates DPN-mediated CNS injury. Accumulating evidence shows that several molecular signaling mechanisms trigger pyroptosis in insulin-producing cells, further leading to the development of DPN. Numerous studies have suggested that certain natural compounds or drugs may possess promising pharmacological properties by modulating inflammasomes and pyroptosis, thereby offering potential preventive and practical therapeutic approaches for the treatment and management of DPN. This review elaborates on the underlying molecular mechanisms of pyroptosis and explores possible therapeutic strategies for regulating pyroptosis-regulated cell death in the pharmacological treatment of DPN.

Asiatic acid inhibits rheumatoid arthritis fibroblast-like synoviocyte growth through the Nrf2/HO-1/NF-κB signaling pathway

Asiatic acid (AA) is generally recognized in the treatment of various diseases and has significant advantages in the treatment of various inflammatory diseases. The treatment of rheumatoid arthritis (RA) with AA is a completely new entry point. RA is a complex autoimmune inflammatory disease, and despite the involvement of different immune and nonimmune cells in the pathogenesis of RA, fibroblast-like synoviocytes (FLS) play a crucial role in the progression of the disease. si-Nrf2 was transfected in RA-FLS and the cells were treated with AA. MTT assay and colony formation assay were used to detect the effect of AA on the viability and formation of clones of RA-FLS, respectively. Moreover, the apoptosis of RA-FLS was observed by Hoechst 33342 staining and flow cytometry. Western blot was applied to measure the expression of the Nrf2/HO-1/NF-κB signaling pathway-related proteins. Compared with the control group, RA-FLS proliferation, and clone formation were significantly inhibited by the increase of AA concentration, and further experiments showed that AA-induced apoptosis of RA-FLS. In addition, AA activated the Nrf2/HO-1 pathway to inhibit NF-κB protein expression. However, the knockdown of Nrf2 significantly offsets the effects of AA on the proliferation, apoptosis, and Nrf2/HO-1/NF-κB signaling pathway of RA-FLS cells. AA can treat RA by inhibiting the proliferation and inducing the apoptosis of RA-FLS. The mechanism may be related to the activation of the Nrf2/HO-1/NF-κB pathway.

Dexmedetomidine Alleviates Lung Oxidative Stress Injury Induced by Ischemia-Reperfusion in Diabetic Rats via the Nrf2-Sulfiredoxin1 Pathway

Oxidative stress injury (OSI) is an important pathological process in lung ischemia-reperfusion injury (LIRI), and diabetes mellitus (DM) can exacerbate this injury. Dexmedetomidine protects against LIRI by reducing OSI. However, the effect of dexmedetomidine on LIRI under diabetic conditions remains unclear. Therefore, this study is aimed at exploring the effects and mechanisms of dexmedetomidine on OSI induced by LIRI in diabetic rats. Rats were randomly divided into control+sham (CS), DM+sham (DS), control+ischemia-reperfusion (CIR), DM+ischemia-reperfusion (DIR), and DM+ischemia-reperfusion+dexmedetomidine (DIRD) groups ( $n=6$ ). In the CS and DS groups, the nondiabetic and diabetic rats underwent thoracotomy only without LIRI. In the CIR, DIR, and DIRD groups, LIRI was induced through left hilum occlusion for 60 min, followed by reperfusion for 120 min in nondiabetic and diabetic rats, and rats in the DIRD group were administered dexmedetomidine (3, 5, and 10 μg/kg). Compared with those in the CS group, the OSI, lung compliance, apoptosis, and oxygenation indices deteriorated in the DS group ( $P<0.05$ ), and these indices were further aggravated in the CIR and DIR groups ( $P<0.05$ ), being the worst in the DIR group ( $P<0.05$ ). Compared to those of the DIR group, the OSI, lung compliance ( $15.8\pm 2.4$ vs. $11.6\pm 1.7\text{ml}/\text{kg}$ ), apoptosis ( $22.5\pm 2.6$ vs. $51.8\pm 5.7$ ), oxygenation ( $381\pm 58$ vs. $308\pm 78\text{mmHg}$ ), and caspase-3 and caspase-9 protein expression indices were attenuated, and Nrf2 and sulfiredoxin1 protein expression was increased in the DIRD group ( $P<0.05$ ). And the lung injury, oxygenation, OSI, and Nrf2 and sulfiredoxin1 protein expression changed in a concentration-dependent manner. In conclusion, dexmedetomidine alleviated lung OSI and improved lung function in a diabetic rat LIRI model through the Nrf2-sulfiredoxin1 pathway.

Acylated Ghrelin Attenuates l-Thyroxin-induced Cardiac Damage in Rats by Antioxidant and Anti-inflammatory Effects and Downregulating Components of the Cardiac Renin-angiotensin System

ABSTRACT

This study investigated the protective effect of acylated ghrelin (AG) against l-thyroxin (l-Thy)-induced cardiac damage in rats and examined possible mechanisms. Male rats were divided into five intervention groups of 12 rats/group: control, control + AG, l-Thy, l-Thy + AG, and l-Thy + AG + [D-Lys3]-GHRP-6 (AG antagonist). l-Thy significantly reduced the levels of AG and des-acyl ghrelin and the AG to des-acyl ghrelin ratio. Administration of AG to l-Thy-treated rats reduced cardiac weights and levels of reactive oxygen species and preserved the function and structure of the left ventricle. In addition, AG also reduced the protein levels of cleaved caspase-3 and cytochrome c and prevented mitochondrial permeability transition pore opening. In the left ventricle of both control + AG-treated and l-Thy + AG-treated rats, AG significantly increased left ventricular levels of manganese superoxide dismutase (SOD2), total glutathione (GSH), and Bcl2. It also reduced the levels of malondialdehyde, tumor necrosis factor-α (TNF-α), interleukin-6, and Bax and the nuclear activity of nuclear factor-kappa B. Concomitantly, in both treated groups, AG reduced the mRNA and protein levels of NADPH oxidase 1, angiotensin (Ang) II type 1 receptor, and Ang-converting enzyme 2. All the beneficial effects of AG in l-Thy-treated rats were prevented by the coadministration of [D-Lys3]-GHRP-6, a selective growth hormone secretagogue receptor subtype 1a antagonist. In conclusion, AG protects against hyperthyroidism-induced cardiac hypertrophy and damage, which is mainly due to its antioxidant and anti-inflammatory potentials and requires the activation of GHS-R1a.

Dexmedetomidine ameliorates lipopolysaccharide-induced acute lung injury by inhibiting the PI3K/Akt/FoxO1 signaling pathway

Purpose

Dexmedetomidine (DEX) has been associated with inflammation, oxidative stress, and apoptosis, but its effects on lipopolysaccharide (LPS)-induced lung injury remain uncertain. The present study explored the effects of DEX on LPS-induced lung injury and studied the possible molecular mechanisms by testing the effects of the phosphoinositide-3 kinase (PI3K) inhibitor LY294002 and BEZ235.

Methods

Seventy C57BL/6 mice were randomly divided into the control, LPS, LPS + DEX, LPS + LY294002, LPS + BEZ235, LPS + DEX + LY294002, and LPS + DEX + BEZ235groups. Lung samples were collected 48 h after LPS treatment.

Results

DEX significantly inhibited LPS-induced increases in the lung weight/body weight ratio and lung wet/dry weight ratio, decreased inflammatory cell infiltration, and decreased the production of proinflammatory factors, such as interleukin-1β (IL-1β), IL-6, and tumor necrosis factor α (TNF-α)in the lungs. DEX also markedly attenuated the increases in malondialdehyde 5 (MDA 5) and inositol-dependent enzyme a (IRE-a), attenuated the decrease in superoxide dismutase 1(SOD-1), reversed the low expression of B-cell lymphoma-2 (Bcl-2), and the high expressions of Bax and Caspase-3. DEX also decreased the expression of phosphorylated PI3K and phosphorylated Akt and increased the expression of phosphorylated forkhead box-O transcription factor 1 (FoxO1). More interestingly, LY294002 or BEZ235 pretreatment significantly abolished the inhibitory effects of DEX on LPS-induced lung inflammation, oxidative stress, and apoptosis.

Conclusions

These data suggest that DEX ameliorates LPS-induced acute lung injury partly through the PI3K/Akt/FoxO1 signaling pathway.

Protective Effect of Dexmedetomidine on Acute Lung Injury via the Upregulation of Tumour Necrosis Factor-α-Induced Protein-8-like 2 in Septic Mice

The aim of the present study was to investigate whether TIPE2 participates in the protective actions of dexmedetomidine (DEX) in a mouse model of sepsis-induced acute lung injury (ALI). We administered TIPE2 adeno-associated virus (AAV-TIPE2) intratracheally into the lungs of mice. Control mice were infected with an adeno-associated virus expressing no transgene. Three weeks later, an animal model of caecal ligation-perforation (CLP)-induced sepsis was established. DEX was administered intravenously 30 min after CLP. Twenty-four hours after sepsis, lung injury was assayed by lung histology, the ratio of polymorphonuclear leukocytes (PMNs) to total cells in the bronchoalveolar lavage fluid (BALF), myeloperoxidase (MPO) activity, BALF protein content and the lung wet-to-dry (W/D) weight ratio. Proinflammatory factor levels in the BALF of mice were measured. The protein expression levels in lung tissues were analysed by Western blotting. The results showed that DEX treatment markedly mitigated sepsis-induced lung injury, which was characterized by the deterioration of histopathology, histologic scores, the W/D weight ratio and total protein levels in the BALF. Moreover, DEX markedly attenuated sepsis-induced lung inflammation, as evidenced by the decrease in the number of PMNs in the BALF, lung MPO activity and proinflammatory cytokines in the BALF. In addition, DEX dramatically prevented sepsis-induced pulmonary cell apoptosis in mice, as reflected by decreases in the number of TUNEL-positive cells, the protein expression of cleaved caspase-9 and cleaved caspase 3 and the Bax/Bcl-2 ratio. In addition, evaluation of protein expression showed that DEX blocked sepsis-activated JNK phosphorylation and NF-κB p65 nuclear translocation. Similar results were also observed in the TIPE2 overexpression group. Our study demonstrated that DEX inhibits acute inflammation and apoptosis in a murine model of sepsis-stimulated ALI via the upregulation of TIPE2 and the suppression of the activation of the NF-κB and JNK signalling pathways.

Dexmedetomidine Alleviates LPS-Induced Neuronal Dysfunction by Modulating the AKT/GSK-3β/CRMP-2 Pathway in Hippocampal Neurons

OBJECTIVE

Dexmedetomidine, an α2-adrenergic receptor agonist, mitigates cognitive dysfunction in elderly patients after surgery with general anesthesia. However, the underlying mechanism by which dexmedetomidine reduces cognitive dysfunction remains to be fully elucidated. The aim of this study was to investigate the effects of dexmedetomidine on lipopolysaccharide (LPS)-induced neuronal dysfunction in cultured hippocampal neurons.

METHODS

LPS, in the presence and absence of dexmedetomidine, was applied to cultured hippocampal neurons to mimic post-surgical inflammation. Neuronal morphology, including neurite outgrowth and synaptic transmission, was observed, and miniature excitatory postsynaptic currents were recorded by electrophysiological patch-clamp.

RESULTS

LPS significantly impaired neurite outgrowth in hippocampal neurons in a concentration- and time-dependent manner, which was reversed by dexmedetomidine treatment. Electrophysiological patch-clamp results showed that LPS induced synaptic transmission dysfunction, which was restored after dexmedetomidine addition. Furthermore, Western blotting assays showed that LPS suppressed the AKT/GSK-3β/CRMP-2 signaling pathway and dexmedetomidine countered the inhibitory effect of LPS by re-activating this pathway.

CONCLUSION

In general, dexmedetomidine protected against the effects of LPS-induced hippocampal neuron damage, including neurite outgrowth and synaptic transmission. Overall, dexmedetomidine modulated the AKT/GSK-3β/CRMP-2 signaling pathway to alleviate LPS-induced neurological dysfunction.

Application of dexmedetomidine for lung injury in elderly patients undergoing one-lung ventilation

Introduction

This study aimed to evaluate the effects of dexmedetomidine (DEX) on lung injury, the oxygenation index and perioperative pulmonary complications in elderly patients who underwent thoracotomy with one-lung ventilation (OLV).

Material and methods

A total of 120 elderly patients with lung cancer were included in the present study. According to the random number table method, these patients were randomly divided into two groups: group D and group C. Patients in group D were intravenously pumped with 0.5 μg/kg/h of DEX before anesthesia. The infusion was completed within 15 min, and anesthesia was induced by venous injection. Patients in group C were pumped with equal volumes of normal saline.

Results

At T2 and T3, compared with group C, group D had a significant decrease in cardiac index, mean arterial pressure and central venous pressure (p < 0.05). At T2, T3 and T4, compared with group C, group D had a significant increase in pH and PaO2 (p < 0.05). At T2, T3 and T4, compared with group C, group D had a significant decrease in Qs/Qt (p < 0.05). At T6, compared with group C, group D had a significant decrease in the supernatant of bronchoalveolar lavage fluid of tumor necrosis factor-α and interleukin 6 (p < 0.05). At T5, compared with group C, group D had a significant decrease in Visual Analogue Scale score (p < 0.05), and a significant increase in Ramsay Sedation Scale score (p < 0.05), and the number of respiratory and cardiovascular events also decreased (p < 0.05).

Conclusions

In elderly patients, dexmedetomidine can reduce Qs/Qt and increase PaO2 during OLV in surgery. It can reduce lung injury. Moreover, DEX reduced respiratory and cardiovascular complications in the perioperative period.

Pretreatment with dexmedetomidine alleviates lung injury in a rat model of intestinal ischemia reperfusion

The aim of the present study was to investigate the antioxidant mechanisms of dexmedetomidine against lung injury during intestinal ischemia reperfusion (IIR) in rats. The model of IIR-induced acute lung injury was established by occluding the superior mesenteric artery (SMA) for 1 h and reperfusing for 2 h using Sprague-Dawley rats. Pathological examination was used to assess the extent of the lung injury. Oxidative stress was evaluated by measuring malondialdehyde, myeloperoxidase and superoxide dismutase in the lung and plasma. The proinflammatory cytokines tumor necrosis factor-α and interleukin-6 were determined via an enzyme-linked immunosorbent assay. The mRNA and protein expression of nuclear factor-erythroid 2 related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) were determined using a reverse transcription-quantitative polymerase chain reaction and western blotting. Pretreatment with dexmedetomidine significantly inhibited the oxidative stress response and proinflammatory factor release caused by IIR compared with the normal saline group (MDA and SOD in lung and plasma, P<0.05; MPO, IL-1β and TNF-α in lung and plasma, P<0.05). Dexmedetomidine improved pulmonary pathological changes in IIR rats compared with the normal saline group. Investigations into the molecular mechanism revealed that dexmedetomidine increased the expression levels of Nrf2 and HO-1 via activating α2 adrenergic receptors compared with the normal saline group. The antagonism of α2 adrenergic receptors may reverse the protective effect of dexmedetomidine on lung injury during IIR, including decreasing the expression levels of Nrf2 and HO-1, elevating the oxidative stress response and increasing the proinflammatory factor release. In conclusion, pretreatment with dexmedetomidine demonstrated protective effects against lung injury during IIR via α2 adrenergic receptors. The Nrf2/HO-1 signaling pathway may serve a function in the protective effect of dexmedetomidine.

Dexmedetomidine attenuates P2X4 and NLRP3 expression in the spine of rats with diabetic neuropathic pain

Purpose:

To evaluate the effects of Dexmedetomidine (Dex) on spinal pathology and inflammatory factor in a rat model of Diabetic neuropathic pain (DNP).

Methods:

The rats were divided into 3 groups (eight in each group): normal group (N group), diabetic neuropathic pain model group (DNP group), and DNP model with dexmedetomidine (Dex group). The rat model of diabetes was established with intraperitoneal streptozotocin (STZ) injections. Nerve cell ultrastructure was evaluated with transmission electron microscopy (TEM). The mechanical withdrawal threshold (MWT) and motor nerve conduction velocity (MNCV) tests documented that DNP rat model was characterized by a decreased pain threshold and nerve conduction velocity.

Results:

Dex restored the phenotype of neurocytes, reduced the extent of demyelination and improved MWT and MNCV of DNP-treated rats (P=0.01, P=0.038, respectively). The expression of three pain-and inflammation-associated factors (P2X4, NLRP3, and IL-IP) was significantly upregulated at the protein level in DNP rats, and this change was reversed by Dex administration (P=0.0022, P=0.0092, P=0.0028, respectively).

Conclusion:

The P2X4/NLRP3 signaling pathway is implicated in the development and presence of DNP in vivo, and Dex protects from this disorder.

Dexmedetomidine Ameliorates Post-CPB Lung Injury in Rats by Activating the PI3K/Akt Pathway

Purpose: To investigate the protective effects of dexmedetomidine (Dex) on post cardiopulmonary bypass (CPB) lung injury in rats and to explore the possibility of underlying mechanisms involving phosphatidylinositol 3-kinase (PI3K)/Akt. Materials and Methods: Forty healthy male Sprague-Dawley rats were randomly divided into five groups (n = 8 for each). A left lung ischemia-reperfusion injury model of CPB was established in all five groups. Rats were given saline, dexmedetomidine (Dex), dimethyl sulfoxide (DMSO), wortmannin (Wtm), and Dex plus Wtm during the CPB process, in Group Saline, Dex, DMSO, Wtm, and Dex + Wtm, respectively. Mean arterial pressure, oxygenation index (OI), and respiratory index (RI) were measured at the following three timepoints: before CPB (T₁), at the onset of opening of the left hilus pulmonis (T₂), and at the end of the CPB process (T₃). At T_3, hematoxylin and eosin (H&E) staining was conducted to evaluate pathology of lung injury. The rate of lung tissue apoptosis was determined by flow-cytometry. The expression of Akt, p-Akt, caspase-3, and caspase-9 was assessed by Western blot. Results: Dex treatment during CPB protected rat lungs from post-CPB lung injury, manifested by improved lung function, mitigated pathological damage, and reduced lung tissue apoptosis. The expression and phosphorylation of Akt was significantly enhanced by Dex treatment compared to the saline/DMSO-treated group. Wtm, a recognized PI3K inhibitor, abolished the protective effect of Dex. The levels of caspase-3 and caspase-9 were also significantly elevated in the Wtm-treated group. Conclusions: Dex reduces post-CPB lung injury in rats, at least partially, by activating the PI3K/Akt pathway and inhibiting lung tissue apoptosis.

Taurine enhances the protective effect of Dexmedetomidine on sepsis-induced acute lung injury via balancing the immunological system

Sepsis, an overwhelming systemic inflammatory disease, is the leading cause of acute lung injury (ALI). Despite plenty of researches have been done, effective drugs treating septic ALI are still eagerly needed in the clinic. Dexmedetomidine (Dex), a potent alpha-2 adrenoreceptor agonist, has been reported to possess antioxidant, anti-apoptosis and anti-inflammatory abilities. Taurine, a kind of intracellular free amino acid, has been used to treat various diseases. This study aimed to explore the combination effect of Dex and Taurine on septic ALI and the underlying mechanism in vivo. The establishment of septic ALI was set up in SD rats by cecal ligation and puncture (CLP) operation. Results indicated that Dex or Taurine could reduce septic ALI-induced cell apoptosis via decreasing caspase-3 activity. However, the combination of Dex or Taurine produced greater effect. Besides that, Dex combined with Taurine could better promote cell proliferation with remarkably elevated Ki67 expression. The combination of Dex and Taurine significantly suppressed the activation of NF-κB pathway via inhibiting P65 phosphorylation and P65 nuclear translocation, leading to the down-regulation of interleukin (IL)-6 and IL-1β. Moreover, co-administration of Dex and Taurine alleviated the imbalance of Th1/Th2 induced by septic ALI to a great extent. All in all, our study suggested the synergistic therapeutic effect of Dex and Taurine on septic ALI.

Dexmedetomidine impairs P‑glycoprotein‑mediated efflux function in L02 cells via the adenosine 5'‑monophosphate‑activated protein kinase/nuclear factor‑κB pathway

Dexmedetomidine (DEX) a type of the anaesthetic that has been widely used in anaesthesia and intensive care. However, whether DEX affects the pharmacokinetics of drugs remains elusive. As hepatic P-glycoprotein (P-gp) serves a critical role in the disposition of drugs, the present study aimed to address whether P-gp function could be affected by DEX in vitro. In the present study, L02 cells (a normal human liver cell line) were exposed to DEX for 24 h and P-gp function was evaluated by the intracellular accumulation of Rhodamine 123. The results indicated that P-gp function was significantly impaired by DEX treatment and that the mRNA levels and protein levels of P-gp were downregulated in a dose- and time-dependent manner. Importantly, DEX-induced downregulation of P-gp was associated with adenosine 5′-monophosphate-activated protein kinase (AMPK) activation, as it was significantly attenuated by AMPK inhibition using dorsomorphin. Furthermore, the results revealed that changes in the subcellular localisation of nuclear factor (NF)-κB following AMPK activation were involved in the P-gp regulation in response to DEX treatment. Collectively, these results suggested that DEX impairs P-glycoprotein-mediated efflux function in L02 cells via the AMPK/NF-κB pathway, which provided direct evidence that the hepatic disposition of drugs may be affected by DEX through the downregulation of P-gp.