Isoflurane Preconditioning May Attenuate Cardiomyocyte Injury Induced by Hypoxia/Reoxygenation Possibly by Regulating miR-363-3p.

This study attempted to explore whether miR-363-3p play a role in the isoflurane (ISO)-mediated protective effect of cardiomyocyte injury induced by hypoxia/reoxygenation (H/R). A myocardial cell injury model was established, and the different preconditioning ISO concentrations were screened and determined. The miR-363-3p level was detected by RT-qPCR. The effects of miR-363-3p on proliferation and apoptosis of H9c2 cells were detected by CCK-8 assay and flow cytometry. Myocardial injury indexes were determined by enzyme-linked immunosorbent assay (ELISA). The interaction of miR-363-3p with the 3'-UTR of the KLF2 gene was confirmed by luciferase reporter gene assay. ISO pretreatment can reduce the up-regulation of miR-363-3p after H/R injury. ISO pretreatment reduces the inhibition of cell viability and the promotion of cell apoptosis induced by H/R stimuli, while the overexpression of miR-363-3p counteracts the protective effect of ISO pretreatment. Meanwhile, ISO pretreatment also reduced the level of markers of H/R-induced myocardial injury. Moreover, luciferase reporter analysis showed that KLF2 was the downstream target gene of miR-363-3p. ISO pretreatment may alleviate H/R-induced cardiomyocyte injury by regulating miR-363-3p.

Effects of Long Noncoding RNA H19 on Isoflurane-Induced Cognitive Dysregulation by Promoting Neuroinflammation.

INTRODUCTION: Isoflurane (ISO) may cause neuronal apoptosis and synaptic disorder during development, and damage long-term learning and memory function. This observation aimed to study the function of H19 in vitro and in vivo tests and the further mechanism was identified. METHODS: ISO cell models and rat models were established and reactive oxygen species (ROS) identified. The viability and apoptosis of HT22 cells were detected by the MTT and flow cytometer. Morris water maze test was conducted to analyze the neurotoxicity of ISO on spatial learning and memory ability. Quantitative PCR was the method to verify the expression of H19. The concentration of inflammatory indicators was identified by enzyme-linked immunosorbent assay. RESULTS: 1.5% and 2% ISO led to the neurotoxicity of HT22 cells and increased expression of H19. Silenced H19 meliorated these adverse impacts of ISO. Interference of H19 exerted neuroprotective roles by repressing modified neurological severity score, inhibiting escape latency, elevating distance and time of target area, and controlling ROS and inflammation. MiR-17-5p might be a promising competing endogenous RNA of H19. The expression of miR-17-5p was reduced in the ISO group and reversed by the absence of H19. CONCLUSION: Our results of in vitro and in vivo assay indicated that the absence of HT22 is a neuroprotective regulator of cognition and inflammation by accumulating miR-17-5p.

Chronic psychological stress impairs germinal center response by repressing miR-155.

Germinal centers (GC) are vital to adaptive immunity. BCL6 and miR-155 are implicated in control of GC reaction and lymphomagenesis. FBXO11 causes BCL6 degradation through ubiquitination in B-cell lymphomas. Chronic psychological stress is known to drive immunosuppression. Corticosterone (CORT) is an adrenal hormone expressed in response to stress and can similarly impair immune functions. However, whether GC formation is disrupted by chronic psychological stress and its molecular mechanism remain to be elucidated. To address this issue, we established a GC formation model in vivo, and a GC B cell differentiation model in vitro. Comparing Naive B cells to GC B cells in vivo and in vitro, the differences of BCL6 and FBXO11 mRNA do not match the changes at the protein level and miR-155 levels that were observed. Next we demonstrated that CORT increase, induced by chronic psychological stress, reduced GC response, IgG1 antibody production and miR-155 level in vivo. The effect of chronic psychological stress can be blocked by a glucocorticoid receptor (GR) antagonist. Similarly, impaired GC B cell generation and isotope class switching were observed. Furthermore, we found that miR-155 and BCL6 expression were downregulated, but FBXO11 expression was upregulated in GC B cells treated with CORT in vitro. In addition, we demonstrated that miR-155 directly down-regulated FBXO11 expression by binding to its 3́-untranslated region. The subsequent overexpression of miR-155 significantly blocked the stress-induced impairment of GC response, due to changes in FBXO11 and BCL6 expression, as well as increased apoptosis in B cells both in vivo and in vitro. Our findings suggest perturbation of GC reaction may play a role in chronic psychological stress-induced immunosuppression through a glucocorticoid pathway, and miR-155-mediated post-transcriptional regulation of FBXO11 and BCL6 expression may contribute to the impaired GC response.

Coregulation of endoplasmic reticulum stress and oxidative stress in neuropathic pain and disinhibition of the spinal nociceptive circuitry.

The accumulation of unfolded or misfolded proteins in the endoplasmic reticulum (ER) lumen leads to ER stress, which is related to cellular reactive oxygen species production. Neuropathic pain may result from spinal dorsal horn (SDH) ER stress. In this study, we examined the cause-effect relationship between ER stress and neuropathic pain using the spinal nerve ligation (SNL) rat model. We showed that ER stress was mutually promotive with oxidative stress during the process. We also tested the hypothesis that spinal sensitization arose from reduced activities of GABA-ergic interneurons and that spinal sensitization was mediated by SDH ER stress. Other important findings in this study including the following: (1) nociceptive behavior was alleviated in SNL rat as long as tauroursodeoxycholic acid injections were repeated to inhibit ER stress; (2) inducing SDH ER stress in healthy rat resulted in mechanical hyperalgesia; (3) blocking protein disulfide isomerase pharmacologically reduced ER stress and nociceptive behavior in SNL rat; (4) cells in the dorsal horn with elevated ER stress were mainly neurons; and (5) whole-cell recordings made in slide preparations revealed significant inhibition of GABA-ergic interneuron activity in the dorsal horn with ER stress vs in the healthy dorsal horn. Taken together, results of the current study demonstrate that coregulation of ER stress and oxidative stress played an important role in neuropathic pain process. Inhibiting SDH ER stress could be a potential novel strategy to manage neuropathic pain.

Establishment of a murine pancreatic cancer pain model and microarray analysis of pain­associated genes in the spinal cord dorsal horn.

There is emerging evidence on the mechanisms of pancreatic cancer pain. Following the establishment of an orthotropic transplantation model of pancreatic cancer, microarray analysis was performed to identify changes in the expression levels of pain­associated genes in the spinal cord. A mouse model of pancreatic cancer­induced pain was established by implanting SW 1990 cells into the pancreases of female BALB/c­nu mice. The survival rate and body weight were measured following orthotropic transplantation. Gross anatomical techniques and hematoxylin and eosin staining were used to analyze the pancreatic tumor tissue. Multiple behavioral tests were also performed to assess pain­associated responses. Additionally, using samples from mice with or without observable pain, microarray analysis was performed to determine the gene expression profiles in the spinal cord dorsal horn. The survival rate of mice with pancreatic cancer was high during the initial 3 weeks post­surgery, although the body weight decreased progressively. Gross anatomical techniques demonstrated that the tumor size increased significantly following the surgery, and this result was confirmed by solid tumor masses in the pancreatic tissues of the mouse model. Observable pain behavioral responses were also examined in the pancreatic cancer model by measuring the mechanical threshold of the abdominal skin, hunching behavior and visceromotor responses. The profiles of 10 pain specific­associated genes in the spinal cord dorsal horn that accurately reflect the molecular pathological progression of disease were also identified. In conclusion, the present study has developed a novel animal model of pancreatic cancer pain in BALB/c­nu mice that resembles human pancreatic cancer pain, and the expression of pain­associated genes in the spinal cord dorsal horn has been profiled. The results of the present study may further the understanding of the molecular mechanisms that mediate pancreatic cancer pain.

Intrathecal infusion of hydrogen-rich normal saline attenuates neuropathic pain via inhibition of activation of spinal astrocytes and microglia in rats.

BACKGROUND: Reactive oxygen and nitrogen species are key molecules that mediate neuropathic pain. Although hydrogen is an established antioxidant, its effect on chronic pain has not been characterized. This study was to investigate the efficacy and mechanisms of hydrogen-rich normal saline induced analgesia. METHODOLOGY/PRINCIPAL FINDINGS: In a rat model of neuropathic pain induced by L5 spinal nerve ligation (L5 SNL), intrathecal injection of hydrogen-rich normal saline relieved L5 SNL-induced mechanical allodynia and thermal hyperalgesia. Importantly, repeated administration of hydrogen-rich normal saline did not lead to tolerance. Preemptive treatment with hydrogen-rich normal saline prevented development of neuropathic pain behavior. Immunofluorochrome analysis revealed that hydrogen-rich normal saline treatment significantly attenuated L5 SNL-induced increase of 8-hydroxyguanosine immunoreactive cells in the ipsilateral spinal dorsal horn. Western blot analysis of SDS/PAGE-fractionated tyrosine-nitrated proteins showed that L5 SNL led to increased expression of tyrosine-nitrated Mn-containing superoxide dismutase (MnSOD) in the spinal cord, and hydrogen-rich normal saline administration reversed the tyrosine-nitrated MnSOD overexpression. We also showed that the analgesic effect of hydrogen-rich normal saline was associated with decreased activation of astrocytes and microglia, attenuated expression of interleukin-1ß (IL-1ß) and tumor necrosis factor-α (TNF-α) in the spinal cord. CONCLUSION/SIGNIFICANCE: Intrathecal injection of hydrogen-rich normal saline produced analgesic effect in neuropathic rat. Hydrogen-rich normal saline-induced analgesia in neuropathic rats is mediated by reducing the activation of spinal astrocytes and microglia, which is induced by overproduction of hydroxyl and peroxynitrite.

Baroreflex sensitivity is impaired in patients with obstructive jaundice.

BACKGROUND: Obstructive jaundice is associated with enhanced susceptibility to hypotensive shock, renal failure, and toxic effects of endotoxin, which results in high perioperative morbidity and mortality. Since the normal arterial baroreflex function is necessary for hemodynamic homeostasis and improving survival in sepsis, this study aimed to determine whether baroreflex sensitivity was impaired in jaundiced patients. METHODS: Thirty-five patients with obstructive jaundice scheduled for surgery were included, and 30 nonjaundiced patients served as controls. A modified Oxford pharmacologic technique was used for evaluating baroreflex sensitivity immediately before the surgery. Potential factors that may affect baroreflex sensitivity in jaundice, such as liver biochemistry, plasma concentrations of methionine-enkephalin, atrial natriuretic peptide and nitrate, were also measured. RESULTS: Patients with obstructive jaundice had decreased sensitivity in both the sympathetic and vagal components of the baroreflex, as compared with the controls (P < 0.01). There was a significant inverse correlation between plasma atrial natriuretic peptide concentration and decreased sympathetic baroreflex sensitivity in the jaundiced group (r = -0.44, P = 0.008). CONCLUSIONS: Baroreflex sensitivity is impaired in patients with obstructive jaundice, which may contribute to their enhanced susceptibility to the well-known perioperative complications. The underlying mechanisms for such a change may be associated with an increased level of plasma atrial natriuretic peptide.