Publication trends of research on COVID-19 and host immune response: A bibliometric analysis.

Introduction: As the first bibliometric analysis of COVID-19 and immune responses, this study will provide a comprehensive overview of the latest research advances. We attempt to summarize the scientific productivity and cooperation across countries and institutions using the bibliometric methodology. Meanwhile, using clustering analysis of keywords, we revealed the evolution of research hotspots and predicted future research focuses, thereby providing valuable information for the follow-up studies. Methods: We selected publications on COVID-19 and immune response using our pre-designed search strategy. Web of Science was applied to screen the eligible publications for subsequent bibliometric analyses. GraphPad Prism 8.0, VOSviewer, and CiteSpace were applied to analyze the research trends and compared the contributions of countries, authors, institutions, and journals to the global publications in this field. Results: We identified 2,200 publications on COVID-19 and immune response published between December 1, 2019, and April 25, 2022, with a total of 3,154 citations. The United States (611), China (353), and Germany (209) ranked the top three in terms of the number of publications, accounting for 53.3% of the total articles. Among the top 15 institutions publishing articles in this area, four were from France, four were from the United States, and three were from China. The journal Frontiers in Immunology published the most articles (178) related to COVID-19 and immune response. Alessandro Sette (31 publications) from the United States were the most productive and influential scholar in this field, whose publications with the most citation frequency (3,633). Furthermore, the development and evaluation of vaccines might become a hotspot in relevant scope. Conclusions: The United States makes the most indispensable contribution in this field in terms of publication numbers, total citations, and H-index. Although publications from China also take the lead regarding quality and quantity, their international cooperation and preclinical research need to be further strengthened. Regarding the citation frequency and the total number of published articles, the latest research progress might be tracked in the top-ranking journals in this field. By analyzing the chronological order of the appearance of retrieved keywords, we speculated that vaccine-related research might be the novel focus in this field.

PTPN18 promotes colorectal cancer progression by regulating the c-MYC-CDK4 axis.

Protein tyrosine phosphatase non-receptor type 18 (PTPN18) is often highly expressed in colorectal cancer (CRC), but its role in this disease remains unclear. We demonstrated that PTPN18 overexpression promotes growth and tumorigenesis in CRC cells and that PTPN18 deficiency yields the opposite results in vitro. Moreover, a xenograft assay showed that PTPN18 deficiency significantly inhibited tumorigenesis in vivo. PTPN18 activated the MYC signaling pathway and enhanced CDK4 expression, which is tightly associated with the cell cycle and proliferation in cancer cells. Finally, we found that MYC interacted with PTPN18 and increased the protein level of MYC. In conclusion, our results suggest that PTPN18 promotes CRC development by stabilizing the MYC protein level, which in turn activates the MYC-CDK4 axis. Thus, PTPN18 could be a novel therapeutic target in the future.

Targeting MUC1-C reverses the cisplatin resistance of esophageal squamous cell carcinoma in vitro and in vivo.

BACKGROUND: The efficacy of chemotherapeutic treatment of esophageal squamous cell carcinoma (ESCC) is limited by drug resistance during. This severely compromises the long-term survival rate of patients. Therefore, reversing chemotherapy resistance in ESCC may improve the therapeutic outcome. Here, we investigated the molecular mechanism of MUC1-C, the C-terminal transmembrane subunit of MUC1 (a transmembrane heterodimer protein), and its role in the reversal of cisplatin sensitivity in ESCC cells. METHODS: We assessed the efficacy of GO-203, a cell-penetrating peptide, as a chemotherapeutic target of MUC1-C using cell proliferation, colony-forming, and transwell assays. Apoptosis was analyzed in GO-203-treated cells by flow cytometry. Tumor xenograft assay was performed in nude mice to corroborate our in vitro findings. RESULTS: GO-203 treatment inhibited cell proliferation and restrained the migration and invasion of cisplatin-resistant ESCC. Moreover, targeting MUC1 resulted in enhanced apoptosis in GO-203-treated cells. These in vitro pro-apoptotic and anti-proliferative effects of GO-203 in combination with cisplatin were validated by in vivo models. Significantly smaller tumor volumes were observed in ESCCs-xenografted nude mice treated with GO-203 in combination with cisplatin compared with mice treated with monotherapy or their control counterparts. We found that blocking MUC1-C with GO-203 significantly reversed the cisplatin resistance in ESCC via modulating Akt and ERK pathways. CONCLUSIONS: Our findings suggest that GO-203 may hold potential as an ancillary therapeutic molecule and a chemosensitizer to improve the outcomes of cisplatin-based chemotherapy especially in patients with cisplatin-resistant ESCC.

Psychological Status Among Anesthesiologists and Operating Room Nurses During the Outbreak Period of COVID-19 in Wuhan, China.

Background: Coronavirus Disease 2019 (COVID-19) caused by a novel strain of coronavirus (SARS-CoV-2) posed a major threat to public health. Anesthesiologists and operating room (OR) nurses are at high risk of occupational exposure to SARS-CoV-2 and developing COVID-19. We conducted a single-center survey to investigate the psychological status and perceived social support among operation room (OR) medical staffs during the outbreak of Coronavirus Disease 2019 (COVID-19). Methods: A total of 197 OR medical staffs were enrolled in the survey. The authors performed a cohort study during the period of Wuhan lockdown and then conducted a longitudinal follow-up after lifting of lockdown. The Patient Health Questionaire-9 (PHQ-9) was used to assess for depression and Generalized Anxiety Disorder-7 (GAD-7) for anxiety. The Multidimensional Scale of Perceived Social Support (MSPSS) was used to assess perceived social support. We compared the psychological status of OR medical staffs before and after lifting of Wuhan lockdown. Results: During the period of city lockdown, 177 (89.8%) had close contact with confirmed COVID-19 cases. The prevalence of depression and anxiety in OR medical staffs was 41.6 and 43.1% under Wuhan lockdown, while 13.2 and 15.7% after lifting of lockdown (P = 0.002, P = 0.004). Logistic regression analysis showed that being female, living in suburb areas, shortage of protective equipment and close contact with COVID-19 patients were associated with a higher risk of depression and anxiety. Perceived social support was negatively correlated with depression and anxiety severity in the OR medical staffs (P < 0.05). Conclusions: OR medical staffs exhibited high incidence of anxiety and depression faced with the high risk of exposure to COVID-19 patients. More social support and social recognition for anesthesiologists and OR nurses might potentially help them relieve their psychological pressure.

GTS-21 ameliorates polymicrobial sepsis-induced hepatic injury by modulating autophagy through α7nAchRs in mice.

BACKGROUND: Previous studies showed that GTS-21, a selective alpha 7 nAchR agonist, can trigger anti-inflammatory effects and improve the survival of septic animals. However, whether GTS-21 affects autophagy responses remains unclear. Here, we tested the hypothesis that GTS-21 ameliorates sepsis-induced hepatic injury by modulating autophagy in mice. METHOD: C57BL/6 male mice were randomly separated and categorized into four groups: the sham group, and CLP group subjected to caecal ligation and puncture (CLP, a model of polymicrobial sepsis). The CLP + GTS-21 group was administered GTS-21 immediately after CLP challenge. α-Bungarotoxin (an alpha 7 nAchR antagonist) was injected before CLP was performed, and then, after CLP challenge, GTS-21 was administered to α-BGT + CLP + GTS-21 group. The hepatic tissue and blood samples were harvested 6 h after the operation. RESULTS: CLP challenge increased TNF-α and IL-6 production, and hepatic enzyme alanine aminotransferase and aspartate transaminase levels. CLP also elevated the expression of hepatic LC3-II, sequestosome-1/p62, Atg7 and Atg5. The administration of GTS-21 inhibited pro-inflammatory cytokine production and hepatic enzymatic marker expression, promoted the expression of LC3-II, Atg7, Atg5, and decreased the expression of p62, which could be reversed by α-BGT treatment. CONCLUSION: Our findings suggested that α7nAchR is involved in diminishing hepatic damage by inhibiting inflammatory responses and improving autophagy in mice with polymicrobial sepsis.

DUB3 deubiquitinates and stabilizes NRF2 in chemotherapy resistance of colorectal cancer.

The transcription factor nuclear factor (erythroid-derived 2)-like 2 (NRF2) is one of the master regulators that control hundreds of genes containing antioxidant response elements (AREs). The NRF2-ARE pathway plays a complex role in colorectal cancer (CRC). NRF2 activity is known to be regulated by KEAP1-CUL3 E3 ligase-mediated ubiquitination, indicating the importance of deubiquitination regulation. However, the deubiquitinase (DUB) of NRF2 remains unknown. Here, by screening a DUB library, we identified DUB3 as a DUB that remarkably stabilized NRF2. Further experiments demonstrated that DUB3 promoted NRF2 stability and transcriptional activity by decreasing the K48-linked ubiquitination of NRF2. Coimmunoprecipitation studies revealed interactions between NRF2 and DUB3, as well as between KEAP1 and DUB3, indicating that NRF2, DUB3, and KEAP1 formed a large functional complex. Importantly, ectopic expression of DUB3 caused NRF2-dependent chemotherapy resistance in colon cancer cell lines. Thus, to the best of our knowledge, our findings are the first to identify DUB3 as a NRF2 DUB and may provide a new strategy against chemotherapy resistance in CRC and other NRF2-related diseases.

Nemo-like kinase (NLK) primes colorectal cancer progression by releasing the E2F1 complex from HDAC1.

Control of E2F1 activity is restricted via its interactions with RB1 and HDAC1. However, the detailed regulatory mechanisms underlying the E2F1/HDAC1 complex remain elusive. Here, we report that Nemo-like kinase (NLK) boosts cell cycle progression, which facilitates tumor development by releasing the E2F1 protein from HDAC1. Deletion of NLK largely blocks colorectal tumor proliferation and development. Moreover, RNA-seq shows that cell cycle is arrested at the G1/S phase in NLK-deficient cells and that the expression of E2F complex-targeted genes are affected, whereas overexpression of NLK but not an NLK mutant restores the wild-type phenotype. Mechanistically, we show that NLK interacts with the E2F1 complex, leading to disassembly of the E2F1/HDAC1 complex and thus diminishing the ability of E2F1 to bind to target gene promoters. Our results indicate that NLK boosts cell proliferation and E2F1 activity and controls the cell cycle switch by releasing HDAC1 from the E2F1 complex.

Penehyclidine hydrochloride inhibits TLR4 signaling and inflammation, and attenuates blunt chest trauma and hemorrhagic shock-induced acute lung injury in rats.

Blunt chest trauma with hemorrhagic shock (THS) frequently induces pulmonary inflammation that leads to acute lung injury (ALI). Penehyclidine hydrochloride (PHC) possesses anti­inflammatory properties that may attenuate the systemic inflammatory response. The present study aimed to evaluate the molecular mechanism of PHC in modifying THS­induced ALI in rats. Rats underwent either THS or a sham procedure. At 6 h subsequent to blunt chest trauma, arterial blood was drawn for blood gas and pro­inflammatory factors analyses, and lung tissue samples were collected to examine pulmonary histopathological alterations, the wet/dry weight ratio, myeloperoxidase activity, and the protein expression levels of Toll-like receptor 4 (TLR4), phosphorylated (p­)p38 mitogen­activated protein kinase (MAPK), nuclear factor (NF)­κB and activator protein­1 (AP­1). THS caused significant reductions in heart rate and mean arterial blood pressure, and was associated with significant increases in tumor necrosis factor­α, interleukin (IL)­6, IL­1ß, p­p38MAPK, NF­κB and AP­1 activation, in addition to TLR4 expression, in the lung. PHC effectively attenuated THS­induced ALI, and inhibited TLR4 expression, reduced the activation of p­p38MAPK, NF­κB and AP­1, and downregulated the expression of pro­inflammatory mediators. In conclusion, the results of the present study demonstrated that PHC may exert an anti­inflammatory effect and attenuate THS­induced ALI by inhibiting the TLR4 signaling pathway. These preclinical findings may offer a novel therapeutic strategy to restrict TLR4 overactivation in ALI.

Muramyl Dipeptide Enhances Thermal Injury-Induced Autophagy and Inflammatory Cytokine Response of Lungs via Activation of NOD2/Rick Signaling Pathway in Rats.

OBJECTIVE: Nucleotide-binding oligomerization domain 2 (NOD2) is the innate receptor of muramyl dipeptide (MDP). Our previous study revealed that MDP could enhance thermal injury-induced inflammatory cytokine production and organ function injury in rats. The present study was to determine the effect of MDP on autophagy and NOD2/receptor-interacting serine/threonine protein kinases (RICK) signaling pathway of lung injury after thermal injury. METHODS: Forty male Sprague-Dawlay rats were randomly divided into four groups: normal control (NC) group, MDP group, Scald group, and MDP + Scald group. Scald group only suffered 20% total body surface area third-degree (TBSA) thermal injury. MDP group was only administered 5.0 mg/kg MDP through the left femoral vein; 5.0 mg/kg MDP was administered through the left femoral vein at 24 h after thermal injury in the MDP + Scald group. RESULTS: TBSA thermal injury (20%) not only significantly increased the plasma inflammatory cytokines production, but also elevated the expression of LC3-I/II, the accumulation of autophagosome in the lung tissue. Compared with the Scald group, MDP + Scald double hit led to more serious inflammatory responses and higher expression of NOD2 mRNA, RICK, NF-κB p65, LC3-I/II, and the accumulation of more autophagosome in the lung tissue. CONCLUSIONS: MDP enhances thermal injury-induced autophagy and proinflammatory cytokine response of lung injury, which could be achieved via activating the NOD2/RICK signaling pathway in rats.

The Role of Erbin in GTS-21 Regulating Inflammtory Responses in MDP-Stimulated Macrophages.

OBJECTIVE: To explore the role of Erbin protein and nucleotide-binding oligomerization domain 2/receptor-interacting serine/threonine protein kinases (NOD2/RICK) in GTS-21 activating cholinergic anti-inflammatory pathway. METHODS: Experiments were randomly divided into four groups: normal control (NC) group, muramyl dipeptide (MDP) group, 10 µg/mL MDP, GTS-21 (GTS) group, 10 µg/mL MDP plus 50 µg/mL GTS-21 (α7 nAChRs agonist), Erbin shRNA interference (sh-Erbin) group: sh-Erbin RNA plus 10 µg/mL MDP and 50 µg/mL GTS-21. We extract specimens at the point of 1, 6, and 24 h after stimulation of MDP in Raw264.7 macrophages. RESULTS: After stimulation of MDP, the NLR2 mRNA, RICK and Erbin protein, nuclear factor (NF)-κB activity, the pro-inflammatory cytokines tumor necrosis factor (TNF)-α and HMGB1 were significantly increased in MDP group (P <0.05). The expression peak of TNF-α is at 1 h. The peak of HMGB1 is at 24 h. Compared with MDP group, the NLR2 mRNA, RICK, NF-κB, TNF-α, and HMGB1 were significantly decreased, but the Erbin was increased in GTS group (P <0.05). Compared with GTS group, the NLR2 mRNA, RICK, NF-κB, TNF-α, and HMGB1 increase in sh-Erbin group (P <0.05). CONCLUSION: GTS-21 could significantly inhibit MDP-induced pro-inflammatory cytokines responses via activating cholinergic anti-inflammatory pathway, and the Erbin might be the key negative regulatory protein in NLR2/RICK signal transduction.

The effect of electroacupuncture at ST36 on severe thermal injury-induced remote acute lung injury in rats.

OBJECTIVE: Acupuncture at ST36 can produce anti-inflammatory effects, which might be associated with vagus nerve activity. This study explored the effects of electroacupuncture (EA) at ST36 on severe thermal injury-induced remote acute lung injury in rats. INTERVENTIONS: Forty male Sprague-Dawley (SD) rats were randomly divided into five groups: (1) the sham (S) group, (2) the thermal injury (TEM) group subjected to 30% total body surface area (30% TBSA) third-degree scald, (3) the EA at ST36 group subjected to EA stimulation at ST36 (3V, 2ms, and 3Hz) after 30% TBSA scald, (4) the EA at non-acupoint group subjected to EA stimulation at non-acupoint after 30% TBSA scald, and (5) the α-bungarotoxin (α7 nicotinic acetylcholine receptor subunit antagonist) group administered 1.0 µg kg(-1) α-bungarotoxin before EA at ST36. MEASUREMENTS AND MAIN RESULTS: Thermal injury of 30% TBSA induced leukocytosis in the alveolar space, interstitial edema, and the pro-inflammatory cytokines interleukin (IL)-1ß, IL-6, and high-mobility group box 1 (HMGB-1); the expression of both HMGB-1 messenger RNA (mRNA) and protein in lung tissue was significantly enhanced. EA at ST36 significantly downregulated the levels of inflammatory cytokines and improved lung tissue injury. However, pretreatment with α-bungarotoxin reversed the effects of electrical stimulation of ST36. CONCLUSIONS: EA at ST36 might have a potential protective effect on severe thermal injury-induced remote acute lung injury via limitation of inflammatory responses in rats.

Muramyl dipeptide enhances thermal injury-induced inflammatory cytokine production and organ function injury in rats.

The bacterial infection following thermal injury is a very important factor of excessive inflammatory response and multiple organ damage. Muramyl dipeptide (MDP) is the key structure of gram-positive bacteria and gram-negative bacteria triggering the innate immune system. The aim of the present study was to determine the effect of MDP on thermal injury-induced inflammatory responses, organ function injury, and mortality in rats. Fifty male Sprague-Dawlay rats were randomly divided into three groups: normal control group, scald group, and MDP group. Scald group only suffered 20% total body surface area third-degree thermal injury. Muramyl dipeptide 5 mg·kg was administered through the femoral vein at 24 h after thermal injury in the MDP group. Plasma inflammatory cytokine levels were measured by enzyme-linked immunosorbent assay. An additional 90 male Sprague-Dawley rats were randomly divided into three groups to observe the survival rate in 72 h. Plasma levels of interleukin-6, interleukin-10, interferon-γ, and high-mobility group box 1; the white blood cell counts; the serum concentrations of alanine aminotransferase, aspartate aminotransferase, total bilirubin, creatine kinase isoenzyme-MB, blood urea nitrogen, and creatinine; and the activity of lung tissue myeloperoxidase significantly increased after thermal injury alone. Compared with the scald group, MDP led to more serious inflammatory responses and organ function damage and higher mortality (P < 0.05, respectively). These data indicate that MDP exacerbates thermal injury-induced inflammatory cytokine production, accompanied by multiple organ dysfunction syndrome and high mortality in rats.

Protective effect of PNU-120596, a selective alpha7 nicotinic acetylcholine receptor-positive allosteric modulator, on myocardial ischemia-reperfusion injury in rats.

The cholinergic anti-inflammatory pathway has been found to exert a protective role in myocardial ischemia-reperfusion injury (MIRI). Alpha7 nicotinic acetylcholine receptor (α7nAChR) is a regulator of cholinergic anti-inflammatory pathway; however, little information is available on the effect of α7nAChR on MIRI. In the present study, we hypothesized that 1-(5-chloro-2,4-dimethoxy-phenyl)-3-(5-methyl-isoxanol-3-yl)-urea (PNU-120596), a potent positive allosteric modulator of α7nAChR, could play a protective role on MIRI. Fifty-five rats were randomly assigned into 4 groups: Sham group, ischemia-reperfusion group, PNU-120596 group, α-bungarotoxin group. Compared with ischemia-reperfusion group, PNU-120596 treatment markedly decreased infarct size, ultrastructural damage, serum creatine kinase, and lactate dehydrogenase. Serum proinflammatory cytokine production, myocardium endothelial activation and neutrophil infiltration, myocardium malondialdehyde were also significantly decreased, accompanied by increased myocardium superoxide dismutase production, in the PNU-120596 group compared with the ischemia-reperfusion group. Meanwhile, we observed a significant inhibition of nuclear factor kappa B activation in PNU-120596 group compared with ischemia-reperfusion group. Pretreatment of α7nAChR-selective antagonist, α-bungarotoxin, abolished all the protective effects of PNU-120596 on MIRI. In conclusion, PNU might have a protective effect against MIRI. Its action mechanisms might be involved in the inhibition of inflammatory responses, attenuation of lipid peroxidation, and suppression of nuclear factor kappa B activity.

Effects of penehyclidine hydrochloride on pulmonary contusion from blunt chest trauma in rats.

BACKGROUND AND OBJECTIVE: Toll-like receptor 4 (TLR4) is widely recognised as a pattern recognition receptor (PRR) in the triggering of innate immunity. Lung inflammation and systemic innate immune responses are dependent on TLR4 activation undergoing pulmonary contusion. Therefore, the author investigated the effects of penehyclidine hydrochloride (PHC) on the expression of TLR4 and inflammatory responses of blunt chest trauma-induced pulmonary contusion. MATERIALS AND METHODS: Male Sprague-Dawley (SD) rats were randomly assigned into three groups: normal control (NC) group, pulmonary contusion (PC) group and penehyclidine hydrochloride treatment (PHC) group. Pulmonary contusion was induced in anesthetised rats at fixed chest impact energy of 2.45J. Lung injury was assessed by the histopathology changes, arterial blood gas and myeloperoxidase (MPO) activity of lung. The serum tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels were measured using enzyme-linked immunosorbent assays (ELISA). The expression of TLR4 was determined by immunohistochemistry. RESULTS: Blunt chest trauma produced leucocytosis in the interstitial capillaries, hypoxemia, and increased MPO activity. The expressions of TNF-α, IL-6 and TLR4 in the lung were significantly enhanced during pulmonary contusion. PHC treatments effectively attenuated pulmonary inflammation responses, as shown by improved pulmonary oxygenation, histopathology damage, decreased the MPO activity, the expressions of TNF-α, IL-6, and TLR4 after lung injury. CONCLUSION: It might be concluded that PHC exhibit anti-inflammatory and protective effects in traumatic lung injury via the inhibition of the TLR4 pathway.

The role of spleen in vagus nerve stimulation for treatment against septic shock in rats.

OBJECTIVE: To investigate the role of spleen in vagus nerve stimulation for treatment against septic shock in rats and its underlying mechanism. METHODS: Sixty-four male Sprague-Dawley (SD) rats were randomly divided into eight groups (n = 8 in each group): sham group, model group, vagotomy group, vagus nerve stimulation group, splenectomy group, splenectomy and vagus nerve stimulation group, common celiac branch vagotomy group, and selective subdiaphragmatic ventral vagotomy group. The septic shock model was reproduced by cecal ligation and puncture (CLP). All the animals were subjected to left cervical vagus nerve isolation or vagotomy, splenectomy was done 3 days before CLP, common celiac branch vagotomy and selective subdiaphragmatic ventral vagotomy were performed after CLP. Mean arterial pressure (MAP) was continuously monitored. Blood was collected 4 hours after CLP for arterial blood gas analysis. The concentrations of tumor necrosis factor-α (TNF-α) and interleukin-1 (IL-1) in plasma and spleen were measured by enzyme-linked immunosorbent assay (ELISA). The spleen mRNA expressions of TNF-α and IL-1 were determined by quantitative reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Compared with sham group, MAP continuously declined, and lactic acid accumulation and metabolic acidosis appeared in model group, and the contents of TNF-α and IL-1 in plasma and spleen, and mRNA expression of TNF-α and IL-1 in spleen were significantly increased in model group C plasma TNF-α (ng/L) 113.24 5.69 vs. 24. 69 2.56, plasma IL-1 (ng/L) 226.33±9. 12 vs. 34. 58 ± 3.45; spleen TNF-α (ng/g) 286. 1216. 66 vs. 41. 33 2. 35, spleen TNF-a mRNA 1. 12+0.08 vs. 0.22± 0. 02, spleen IL-1 (ng/g) 447. 34 ± 12. 36 vs. 42. 95 ± 2. 33, spleen IL-1 mRNA 0. 93 ± 0. 06 vs. 0. 28 ± 0. 02, all P<0. 013. Compared with model group, lowering of MAP was retarded, lactic acid value and the negative value of base excess (BE) were significantly decreased, the contents of TNF-α and IL-1 in plasma and spleen, and mRNA expression of TNF-α and IL-1 in spleen Uplasma TNF-α (ng/L) 41.00 ± 3.22, plasma IL-1 (ng/L) 63.29±2. 56; spleen TNF-α (ng/g) 74. 22-3.12, spleen TNF-α mRNA 0. 32± 0. 03, spleen IL-1 (ng/g) 81. 54- 5. 48, spleen IL-1 mRNA 0. 35+0.03] were also significantly decreased in vagus nerve stimulation group (P<0. 05 or P<0. 01). However, vagus nerve stimulation after splenectomy failed to show the similar effect as seen in the vagus nerve stimulation group. Compared with vagus nerve stimulation group, the contents of TNF-a and IL-1 in plasma and spleen, and mRNA expression of TNF-α and IL-1 in spleen Eplasma TNF-a (ng/L) 118.38±8. 52, plasma IL-1 (ng/L) 252. 23 9. 55; spleen TNF-α (ng/g) 297.88± 5.44, spleen TNF-a mRNA 0. 68+0. 04, spleen IL-1 (ng/g) 450. 26 12. 45, spleen IL-1 mRNA 0. 96±0. 063 were significantly increased in common celiac branch vagotomy group (P<0. 05 or P< 0. 01). In the selective subdiaphragmatic ventral vagotomy group similar effect with that of the vagus nerve stimulation group was found. CONCLUSION: Vagus nerve stimulation fails to protect against septic shock in rats subjected to splenectomy or common celiac branch vagotomy, indicating that the spleen may be a vital target of the cholinergic anti-inflammatory pathway which is functionally linking with the spleen via the common celiac branch of vagus nerve.

[Protective effects of nicotine on inflammatory cytokines in myocardial ischemia/reperfusion injury in rats].

OBJECTIVE: To investigate the effect of nicotine on inflammatory cytokines in myocardial ischemia/reperfusion (I/R) injury in rat. METHODS: Fifty male Sprague-Dawley (SD) rats were divided into five groups by random numbers table (each n=10): sham operation group (S group), I/R group, nicotine 400 µg/kg group (H group), nicotine 40 µg/kg group (L group) and α-bungarotoxin (α-BGT,1 µg/kg) group. The anterior descending branch of left coronary artery was occluded for 30 minutes followed by 90 minutes reperfusion to reproduce myocardial I/R injury rat model, while in S group the anterior descending branch of left coronary artery was only exposed without occlusion procedure. Thirty minutes before myocardial ischemia, drugs in corresponding doses were given intravenously via jugular vein. At the end of 90 minutes of reperfusion, blood samples were collected from carotid artery to determine the levels of tumor necrosis factor-α (TNF-α), interleukin-8 (IL-8), IL-10, MB isoenzyme of creatine kinase (CK-MB), and cardiac troponin I (cTnI), then the animals were sacrificed and the hearts were harvested for pathological study and determination of myeloperoxidase (MPO) activity. Immunohistochemistry and reverse transcription- polymerase chain reaction (RT-PCR) were used to assess intercellular adhesion molecule-1 (ICAM-1) protein and mRNA expression in heart tissue. RESULTS: Compared with the S group, the concentrations of TNF-α, IL-8, IL-10, CK-MB, cTnI, MPO activity, ICAM-1 protein and mRNA expression were significantly increased in I/R group [TNF-α (ng/L): 158.7±32.7 vs. 31.5±5.8, IL-8 (ng/L): 0.71±0.06 vs. 0.30±0.04, IL-10 (ng/L): 69.0±7.8 vs. 41.4±4.3, CK-MB (U/L): 2 540±169 vs. 1 120±120, cTnI (µg/L): 26.2±4.6 vs. 0.9±0.2, MPO (U/g): 4.2±0.6 vs. 1.6±0.4, ICAM-1 protein: 0.210±0.025 vs. 0.100±0.018, ICAM-1 mRNA: 1.82±0.23 vs. 1.18±0.20, P<0.05 or P<0.01]. Injury to myocardial ultrastructure was worse in I/R group. Compared with the I/R group, the plasma levels of TNF-α and IL-8 were lower [TNF-α (67.3±9.8) ng/L, IL-8 (0.47±0.04) ng/L], IL-10 was higher [(147.5±12.5) ng/L], CK-MB, cTnI, MPO, ICAM-1 protein and mRNA were lower obviously in H group [CK-MB (1 282±145) U/L, cTnI (4.7±1.4) µg/L, MPO (2.5±0.4) U/g, ICAM-1 protein 0.140±0.026, ICAM-1 mRNA 1.31±0.25, P<0.05 or P<0.01]. Injury to the myocardial ultrastructure was less marked in H group. The indexes of those in L group and α-BGT group compared with I/R group were not statistically significantly different. CONCLUSION: Nicotine can block endothelial expression of adhesion molecules and neutrophil adhesion and infiltration to promote a balance of anti-inflammatory and pro-inflammatory response, thus prevents excessive inflammatory response to myocardial I/R injury in rat.

Effect of vagus nerve stimulation on thermal injury in rats.

OBJECTIVE: To investigate the effects of vagus nerve stimulation on haemodynamics, pulmonary histopathology, arterial blood gas and pro-inflammatory responses to thermal injury. INTERVENTIONS: Forty-eight male Sprague-Dawley (SD) rats were randomly divided into six equal groups: normal control (NC) group; thermal injury (TEM) group subjected to 40% total body surface area (%TBSA) third-degree thermal injury; vagotomy (VGX) group subjected to bilateral cervical vagotomy after thermal injury; electrical stimulation (STM) group subjected to bilateral cervical vagotomy plus the left vagus nerve trunk electrical stimulation (5 V, 2 ms and 1 Hz) after thermal injury; the antagonist of muscarinic acetylcholine receptor (MRA) group administrated with atropine (0.1 mg kg(-1)) before electrical stimulation and the antagonist of nicotinic acetylcholine receptor (NRA) group administrated with hexamethonium (10 mg kg(-1)) before electrical stimulation. MEASUREMENTS AND MAIN RESULTS: The haemodynamics, histopathology of lung tissue, arterial blood gas, lactic acid, tumour necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) levels were measured. Vagus nerve electrical stimulation not only significantly increased the mean arterial pressure (MAP) and heart rate (HR), but also decreased the infiltration of inflammatory cells into interstitial and alveolar spaces after thermal challenge and attenuated TNF-alpha and IL-6 production. Hexamethonium pre-treatment significantly reversed the effects of vagal electrical stimulation, but atropine administration before electrical stimulation had no such effects. CONCLUSIONS: Direct electrical stimulation of the vagus nerve might produce therapeutic effect on thermal injury. The effect may be realised by limiting the inflammatory response via nicotinic acetylcholine receptors in rats.

Effects of propofol on pro-inflammatory cytokines and nuclear factor kappaB during polymicrobial sepsis in rats.

Nuclear factor kappa B (NF-kappaB) plays a central role in regulating the transcription of several genes associated with sepsis/septic shock. Therefore, the author investigated the effects of propofol on the plasma tumor necrosis factor alpha and interleukin 6 (TNF-alpha and IL-6) levels and NF-kappaB activation during polymicrobial sepsis in rats. Male Sprague-Dawlay rats were subjected to cecal ligation and puncture (CLP, a model of polymicrobial sepsis) or sham operation. The animals were randomly assigned into four equal groups (n = 10): sham CLP group, CLP group, PPF (propofol) I group and PPF II group. Thirty minutes before CLP, propofol (5 and 10 mg kg(-1) h(-1), respectively) was infused continuously through the left femoral vein cannula in PPF I group or PPF II group, CLP group and sham CLP group receiving 0.9% saline only at the rates of 5 ml kg(-1) h(-1). The right femoral artery was cannulated to monitor mean arterial pressure (MAP) and heart rates (HR). CLP produced progressive hypotension and a first increase followed by a decrease in HR. The plasma TNF-alpha and IL-6 levels and the hepatic NF-kappaB activation significantly increased after CLP alone. Compared with CLP group, propofol treatment reversed hypotension, slightly steadied heartbeats, and decreased the plasma TNF-alpha and IL-6 levels, and significantly suppressed NF-kappaB activation. Propofol has inhibited the hepatic NF-kappaB activation and the pro-inflammatory cytokine response during polymicrobial sepsis in rats.

The protective effect of the cholinergic anti-inflammatory pathway against septic shock in rats.

To investigate the effects of the cholinergic anti-inflammatory pathway on hemodynamics, blood biochemistry, the plasma TNF-alpha level, and the nuclear factor-kappaB (NF-kappaB) activation during septic shock, male Sprague-Dawley rats were subjected to cecal ligation and puncture (CLP, a model of polymicrobial sepsis) or sham operation. Forty-eight rats were randomly assigned into six equal groups: sham CLP group; CLP group; VGX group was subjected to bilateral cervical vagotomy after CLP; STM group was subjected to bilateral cervical vagotomy after CLP plus the left vagus nerve trunk electrical stimulation; THA group was administered tetrahydroaminoacridine after CLP and bilateral cervical vagotomy; and alpha-BGT group was administered alpha-bungarotoxin before electrical stimulation of the vagus nerve. The right carotid artery was cannulated to monitor MAP. The plasma TNF-alpha level was measured using enzyme-linked immunosorbent assays. The hepatic NF-kappaB activation was determined by Western blotting. Cecal ligation and puncture produced progressive hypotension. Serum aspartate transaminase and alanine transaminase levels significantly increased after CLP challenge. The plasma TNF-alpha level and the hepatic NF-kappaB activation significantly increased after CLP alone or with bilateral cervical vagotomy compared with sham-operated group. Application of constant voltage pulses to the caudal vagus trunk significantly prevented the development of CLP-induced hypotension, alleviated the hepatic damage, and reduced the plasma TNF-alpha production, but electrical stimulation had no effect on the hepatic NF-kappaB activation. Tetrahydroaminoacridine administration after bilateral cervical vagotomy reversed hypotension and attenuated the plasma TNF-alpha response; in addition, it had no effect on the hepatic NF-kappaB activation. alpha-Bungarotoxin pretreatment significantly reversed the inhibitory effect of vagal electrical stimulation, but it had no effect on the hepatic NF-kappaB activation. Our results showed that the cholinergic anti-inflammatory pathway might produce a potential protective effect on polymicrobial sepsis in rats.

Effects of ketamine on proinflammatory cytokines and nuclear factor kappaB in polymicrobial sepsis rats.

AIM: To explore the effects of ketamine on hemo-dynamics, plasma proinflammatory cytokine (TNF-alpha and IL-6) levels and nuclear factor kappa B (NF-kappaB) activation during polymicrobial sepsis. METHODS: Male Sprague-Dawley rats were subjected to cecal ligation and puncture (CLP) or sham operation. The rats were randomly assigned into four equal groups: sham CLP group, CLP group, ketamine (KT) I group and KT II group. Thirty minutes before CLP, ketamine (5 mg/kg per hour and 10 mg/kg per hour, respectively) was infused continuously through the left femoral vein cannula in KT I group or KT II group. Sham CLP group and CLP group received 0.9% saline only (5 mL/kg per hour). The right femoral artery was cannulated to monitor mean arterial pressure (MAP) and heart rates (HR),and draw blood samples. The proinflammatory cytokine (TNF-alpha and IL-6) levels of plasma were measured using enzyme-linked immunosorbent assays (ELISA). The hepatic NF-kappaB activation was determined by Western blot and HPIAS 2000 image analysis system. Twenty hours after CLP, the rats were killed by right femoral artery phlebotomization. RESULTS: CLP produced progressive hypotension, and a first increase followed by a decrease in HR. The hypotension was prevented, and the HR was slightly steady in ketamine treated rats. TNF-alpha levels of plasma reached a peak value at 2 h after CLP. Ketamine (KT I group or KT II group) caused a significant decrease compared with CLP group at 2, 5 and 9 h time points after CLP (14.3 +/- 1.9 vs 4.3 +/- 0.9, 9.7 +/- 1.4 vs 4.3 +/- 0.9; 9.3 +/- 1.5 vs 4.3 +/- 0.9, 8.7 +/- 1.4 vs 4.3 +/- 0.9; 6.0 +/- 1.5 vs 5.0 +/- 1.7, 5.3 +/- 0.8 vs 5.0 +/- 1.7; P < 0.01, respectively). The IL-6 levels of plasma firstly ascended and then descended in CLP group, and reached a peak value at 9 h after CLP. Ketamine (KT I group or KT II group) caused a significant decrease compared with CLP group at 5, 9 or 20 h after CLP (135.0 +/- 52.6 vs 60.0 +/- 16.3, 112.5 +/- 52.6 vs 60.0 +/- 16.3; 410.0 +/- 68.7 vs 62.5 +/- 12.5, 250.0 +/- 28.0 vs 62.5 +/- 12.5; 320.0 +/- 25.9 vs 52.5 +/- 10.1, 215.0 +/- 44.6 vs 52.5 +/- 10.1; P < 0.05, respectively). The IL-6 levels of plasma in KT II group were lower than those of KT I group at 9 h after CLP (250.0 +/- 28.0 vs 410.0 +/- 68.7; P < 0.05). In addition, CLP increased hepatic NF-kappaB expression compared with sham CLP. Ketamine suppressed NF-kappaB activation in a dose-dependent manner at 4 h after CLP (237.7 +/- 3.5 vs 246.9 +/- 3.1; P < 0.05). CONCLUSION: Ketamine stabilizes the hemodynamics, attenuates the proinflammatory cytokine responses, and inhibits hepatic NF-kappaB activation. These findings suggest that ketamine has protective effects against polymicrobial sepsis in rats.