Interleukin-6 Immunoreactivity Research Articles

Investigation of the effect of Myricetin on Cisplatin-induced liver hepatotoxicity.

Cisplatin, a widely used anticancer agent, induces hepatotoxicity alongside organ damage. Understanding Cisplatin's toxicity mechanism and developing preventive measures are crucial. Our study explores Myricetin, a flavonoid, for its protective effects against Cisplatin-induced hepatotoxicity. In our study, a total of 32 Wistar albino male rats were utilized, which were categorized into four distinct groups: Control, Myricetin, Cisplatin, and Myricetin+Cisplatin. For the histological assessment of hepatic tissues, hematoxylin-eosin and periodic acid Schiff staining were employed, alongside immunohistochemical measurements of TNF-α, interleukin-17, and interleukin-6 immunoreactivity. Additionally, aspartate transaminase and alanine transaminase values were examined by biochemical analysis. In the histological evaluation of the tissues, a normal healthy cell structure and a strong periodic acid Schiff (+) reaction were observed in the hepatocyte cells in the tissues of the Control and Myricetin groups, while intense eosinophilia, minimal vacuolization, congestion, and sinusoidal expansions were observed in the hematoxylin-eosin stainings, and a decrease in the positive reaction in the periodic acid Schiff staining was observed in the Cisplatin group. Consistent with these histological findings, an increase in TNF-α, interleukin-17, and interleukin-6 expressions (p<0.0001) and a concomitant increase in aspartate transaminase and alanine transaminase values were observed in the Cisplatin group. In the group protected by Myricetin, a significant improvement was observed in all these histological and biochemical values. Cisplatin induces notable histopathological alterations in the liver. In this context, Myricetin exhibits the potential to alleviate Cisplatin-induced damage by modulating histological parameters and biochemical processes.

Timokinonun izoproterenol ile indüklenen sıçan aortu üzerindeki sitoprotektif etkilerinin değerlendirilmesi

Purpose: The aim of this study was to evaluate histologically and immunohistochemically the cytoprotective effects of thymoquinone (THQ) against isoproterenol (ISO)-induced aortic tissue damage.&#x0D; Materials and Methods: Rats were divided into four groups (n=8). Control group (Control); were untreated rats, Thymoquinone group (THQ); 20 mg / kg intragastrically (ig) THQ at 24 hour intervals for 8 days, Isoproterenol group (ISO); on the 7th and 8th day of the experiment, 100 mg/kg subcutaneous (sc) ISO (dissolved in 1 ml sterile distilled water) was given at 24 hour intervals. Thymoquinone + Isoproterenol group (THQ+ISO); THQ was administered ig at 20 mg/kg for 8 days, and 100 mg/kg ISO was administered on day 7 and day 8 of the experiment. Aortic tissues and blood were collected from rats. Tissues were stained by hematoxylin-eosin and immunohistochemically by interleukin-6 (IL-6) and interleukin-17 (IL-17). TNF-α, ELISA was examined in blood sera.&#x0D; Results: Aortic wall thickness was found to be increased in the ISO group compared to the control and THQ groups. In addition, IL-6 and IL-17 immunoreactivity increased in this group. IL-17 height was statistically significant. THQ corrected both the increase in wall thickness and the expression levels of IL-6 and IL-17. TNF-α was found to be decreased in the ISO group, but no statistically significant difference was observed between the groups.&#x0D; Conclusion: THQ serves as a cytoprotective agent

Primary culture of the rat spinal dorsal horn: a tool to investigate the effects of inflammatory stimulation on the afferent somatosensory system

One maladaptive consequence of inflammatory stimulation of the afferent somatosensory system is the manifestation of inflammatory pain. We established and characterized a neuroglial primary culture of the rat superficial dorsal horn (SDH) of the spinal cord to test responses of this structure to neurochemical, somatosensory, or inflammatory stimulation. Primary cultures of the rat SDH consist of neurons (43%), oligodendrocytes (35%), astrocytes (13%), and microglial cells (9%). Neurons of the SDH responded to cooling (7%), heating (18%), glutamate (80%), substance P (43%), prostaglandin E2 (8%), and KCl (100%) with transient increases in the intracellular calcium [Ca2+]i. Short-term stimulation of SDH primary cultures with LPS (10 μg/ml, 2 h) caused increased expression of pro-inflammatory cytokines, inflammatory transcription factors, and inducible enzymes responsible for inflammatory prostaglandin E2 synthesis. At the protein level, increased concentrations of tumor necrosis factor-α (TNFα) and interleukin-6 (IL-6) were measured in the supernatants of LPS-stimulated SDH cultures and enhanced TNFα and IL-6 immunoreactivity was observed specifically in microglial cells. LPS-exposed microglial cells further showed increased nuclear immunoreactivity for the inflammatory transcription factors NFκB, NF-IL6, and pCREB, indicative of their activation. The short-term exposure to LPS further caused a reduction in the strength of substance P as opposed to glutamate-evoked Ca2+-signals in SDH neurons. However, long-term stimulation with a low dose of LPS (0.01 μg/ml, 24 h) resulted in a significant enhancement of glutamate-induced Ca2+ transients in SDH neurons, while substance P-evoked Ca2+ signals were not influenced. Our data suggest a critical role for microglial cells in the initiation of inflammatory processes within the SDH of the spinal cord, which are accompanied by a modulation of neuronal responses.

Expression of interleukin 6 and tumor necrosis factor alpha in endometriotic tissues: an immunohistochemical study

Purpose: The aim of this study is to investigate Tumor necrosis factor alpha (TNF-α) and Interleukin 6 (IL-6) expressions in normal and endometriotic human tissue using immunohistochemical methods.Materials and Methods: This study examined tissue sections obtained from the tissue biopsies of ectopic endometrium taken from 24 women between the ages of 20 to 40 years. Additionally, the tissue sections taken from the normal endometrium obtained from 10 patients without any endometrial dysfunction due to dilation or curettage were also evaluated, as the control group. Tissue sections prepared by light microscopic and immunohistochemical methods were examined under a light microscope.Results: In the control group TNF-α and IL-6 expressions were identified at varying levels, from weak to moderate, in surface and glandular epithelium; however, there was no evidence of a significant staining in the stromal cells. It is found that TNF-α and IL-6 immunoreactivity in the endometriotic tissues were significantly increased in the epithelial cells, stromal cells and macrophages compared to the control endometrium. Expressions of TNF-α and IL-6 were both strong in the ectopic endometrial tissues. Conclusion: We conclude that TNF-α and IL-6 are important cytokines involved in the pathogenesis of the endometriosis.

Association between adipokines and thyroid carcinoma: a meta-analysis of case-control studies

BackgroundThe incidence of thyroid carcinoma is increasing all over the world. Some studies have suggested that the change of adipokines expression can induce thyroid carcinoma. However, other studies have come to the opposite conclusion. Therefore, we studied the relationship between adipokines and thyroid carcinoma.MethodsDatabases—PubMed, Cochrane Library, SinoMed, CNKI, Wanfang, and clinical trial registries were searched. A meta-analysis was then performed through a fixed or random-effects model to calculate I values for heterogeneity analysis.ResultsTwenty-nine articles were finally included for analysis. The level of serum tumor necrosis factor-alpha (TNF-α) [standardized mean difference (SMD) =1.31, 95% confidence interval (95% CI): 0.35 to 2.28, I2 = 98%, P = 0.008] and the ratio of TNF-α immunoreactivity in tissues [odds ratios (OR) =6.36, 95% CI: 1.92 to 21.05, I2 = 66%, P = 0.002] in thyroid carcinoma are significantly higher than those in control. The serum interleukin-6 (IL-6) in patients with thyroid carcinoma is higher than that in control (SMD = 1.04, 95% CI: 0.40 to 1.67, I2 = 96%, P = 0.001). There is no significant difference of the ratio of IL-6 immunoreactivity in tissues between carcinoma and control (OR = 1.23, 95% CI: 0.62 to 2.43, I2 = 86%, P = 0.55). The ratio of leptin immunoreactivity in tissues is significantly associated with the risk of thyroid carcinoma (OR = 12.21, 95% CI: 3.36 to 44.40, I2 = 85%, P < 0.00001). However, after analyzing the expression level of serum adiponectin in three studies, no significant difference is found between thyroid carcinoma and the control (P = 0.81).ConclusionsAdipokines (TNF-α, IL-6 and leptin) show a strong relationship between elevated concentrations (in serum and/or tissue) and thyroid carcinoma. However, the association between adiponectin and thyroid carcinoma needs further research.

The NADPH oxidase NOX2 as a novel biomarker for suicidality: evidence from human post mortem brain samples.

Recent evidence points towards a role of oxidative stress in suicidality. However, few studies were carried out on the sources of reactive oxygen species (ROS) in subjects with suicidal behaviour. We have previously demonstrated that the NADPH oxidase NOX2-derived oxidative stress has a major role in the development of neuropathological alterations observed in an animal model of psychosis. Here, we investigated the possible increase in NOX2 in post mortem brain samples of subjects who died by asphyctic suicide (AS) compared with controls (CTRL) and subjects who died by non-suicidal asphyxia (NSA). We found that NOX2 expression was significantly higher in the cortex of AS subjects than in the other two experimental groups. NOX2 immunostaining was mainly detected in GABAergic neurons, with a minor presence of NOX2-positive-stained cells in glutamatergic and dopaminergic neurons, as well as astrocytes and microglia. A sustained increase in the expression of 8-hydroxy-2'-deoxyguanosine, an indirect marker of oxidative stress, was also detected in the cortex of AS subjects, compared with CTRL and NSA subjects. A significant elevation in cortical interleukin-6 immunoreactivity in AS subjects suggested an involvement of cytokine-associated molecular pathways in NOX2 elevations. Our results suggest that the increase in NOX2-derived oxidative stress in the brain might be involved in the neuropathological pathways leading to suicidal behaviour. These results may open innovative insights in the identification of new pathogenetic and necroscopic biomarkers, predictive for suicidality and potentially useful for suicide prevention.

Expression of proinflammatory cytokine interleukin-6 in tissue samples of human prostate obtained by needle biopsy

Interleukin-6 (IL-6) has been associated with the development of prostate cancer. The aim of the study was to clarify whether IL-6 expression in prostate tissue could be a useful marker in differentiation of prostate diseases in small foci by pathologist visual scoring. Archival paraffin-embedded specimens of benign prostate hyperplasia (BPH), high-grade prostatic intraepithelial neoplasia (PIN), prostatitis and prostate adenocarcinoma were studied by immunohistochemistry with a mouse monoclonal antibody IL-6 using the streptavidin–biotin method. Significantly, lower IL-6 immunoreactivity was observed in normal epithelial cells (p=0.000) and basal cells (p=0.000) in the samples of prostate adenocarcinoma in comparison to the samples with BPH, PIN and prostatitis. There was no significant difference in IL-6 expression in malignant and premalignant cells (p=0.814) as well as in stromal cells among the four diagnoses (p=0.22). IL-6 was expressed in normal epithelial cells, premalignant epithelial cells and malignant epithelial cells as well as in stromal cells. However, in our research IL-6 was of limited utility as a single marker for differential diagnosis of the prostate diseases in small foci needle biopsy by pathologist visual scoring. The standardization of immunohistochemical (IHC) staining protocol for IL-6 is required to determine IL-6 expression in order to avoid possible misinterpretation of the IHC results.

IL-6 and PACAP Receptor Expression and Localization after Global Brain Ischemia in Mice

Pituitary adenylate cyclase-activating polypeptide (PACAP) exerts a neuroprotective action against ischemic damage. This action is mediated by the interleukin-6 (IL-6) pathway. However, as the expression patterns of PACAP receptors and IL-6 following ischemia are not understood, we evaluated them in the mouse hippocampus in response to ischemia induced by bilateral common carotid artery occlusion. Real-time PCR determination of PAC1R mRNA expression in the hippocampus was significantly elevated on day 7 after ischemia. VPAC1R mRNA expression was significantly decreased 3 days after the ischemic episode, while VPAC2R mRNA expression showed a nonsignificant tendency to increase on day 7. IL-6 mRNA expression was significantly increased on day 3 and peaked on day 7 after ischemia. The mRNA expression of activity-dependent neuroprotective protein, which is a neuroprotective factor stimulated by PACAP, remained virtually unchanged in response to ischemia. IL-6 immunoreactivity was detected in the CA1 pyramidal cell layer and colocalized with the neuronal marker NeuN on day 1 after ischemia. On day 3, irregularly shaped IL-6-immunopositive cells colocalized with the astrocytic marker glial fibrillary acidic protein but not with the microglial marker Iba1. PAC1R immunoreactivity co-labeled with IL-6 immunoreactivity. These results suggest that PACAP could stimulate IL-6 secretion by neurons during the acute phase after an ischemic episode and thereafter by astrocytes during the subacute phase.

The association of mast cells and serotonin in children with chronic abdominal pain of unknown etiology

BackgroundAbdominal pain of unknown origin affects up to 20% of school-aged children. Evaluation of children is symptom-based without clear guidelines to investigate molecular mechanisms of abdominal pain. Aberrant molecular mechanisms may increase intestinal permeability leading to interactions between the immune and nervous systems, subclinical inflammation, and visceral pain. This study evaluated the association between interleukin-6 (IL-6), mast cell infiltrates, and serotonin (5-HT) levels in gastrointestinal (GI) biopsies, with perceived abdominal pain in a pediatric cohort.MethodsClinical data and biopsy samples from pediatric patients (n = 48) with chronic abdominal pain, with and without inflammation were included. Formalin-fixed paraffin-embedded GI biopsies were sectioned and immunohistochemistry performed for IL-6 and 5-HT; mast cells were identified with toluidine blue stain. Histological findings were compared to self-reported abdominal pain between groups.ResultsThere was significantly greater IL-6 immunoreactivity in biopsies with confirmed histologic inflammation (p = 0.004). There was a greater number of mast cells per HPF in non-inflammatory biopsies (3.5 ± 2.9) compared to the inflammatory biopsies (2.6 ± 1.8) p = 0.049. The non-inflammatory biopsy group was significantly less likely to respond to standard treatment as evidenced by higher pain reports (p = .018). Mast cells (p = .022) and 5-HT (p = .02) were significantly related to abdominal pain scores.ConclusionsA potential association between self-reported abdominal pain, number of mast cells, and 5-HT levels, which may contribute to perceived GI pain in pediatric patients may exist.

Abstract 1334: Intratumoral soluble interleukin-6 receptor associated with disease progression in colorectal cancer

Abstract Purpose. Interleukin-6 (IL-6) binds not only to membrane form but also to soluble IL-6 receptor (sIL-6R), derived from the extracellular part of the membrane receptor. Although most soluble receptors act as functional antagonists to their cytokine, sIL-6R plays a role in agonistic activity. The aim of this study was to clarify the relationship between concentration of intra-tumoral soluble interleukin-6 receptor levels and cancer progression in colorectal cancer patients, and to clarify its kinetics with clinical outcome. Methods. We studied 161 patients undergoing surgery for colorectal cancer. We measured concentrations of sIL-6R in tumors and normal mucosa, and in supernatants from colonic cancer cell lines. Expressions of IL-6, membranous IL-6R and gp130 were evaluated by immunohistochemically Results. The net balance between the concentration of sIL-6R in cancer tissue and normal mucosa (sIL-6R Ca/N expression ratio: the cancer tissue sIL-6R concentration divided by normal mucosa sIL-6Rntration) was 1.262 ± 1.156. The decreased sIL-6R Ca/N expression ratio was significantly associated with T classification (p=0.0076), distant metastasis (p=0.0102), UICC stage (p=0.0251) and poor prognosis (p=0.0003). In Cox multivariate analysis, distant metastasis and decreased sIL-6R Ca/N expression ratio were independent risk factors for poor prognosis. Colon cancer cell lines produced sIL-6R, and the production was exaggerated by IL-1beta stimulation, and was suppressed by the addition of IL-1 receptor antagonist. Immunohistochemically, IL-6, membranous IL-6R and gp130 were intensely expressed in cancer cell specifically, and IL-6 expression in cancer cytoplasm was associated with poor prognosis (p=0.0266). The decreased levels of sIL-6R Ca/N expression ratio in cancer tissue was inversely correlated with the intense IL-6 immunoreactivity in cancer cytoplasm (p=0.0088). Conclusion: Relative decrease in sIL-6R in the tumor stroma which reflects increased IL-6/sIL-6R affinity may play a key role in the progression of colorectal carcinoma via IL-6 tran-signaling. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1334.

Abstract 1756: Automated digital analysis of interleukin-6 (IL-6) expression in a prostate cancer (PCa) matched case-control outcome based tissue microarray (TMA) design set

Abstract IL-6 is a multifunctional cytokine that has been involved in modulation of growth and differentiation in several malignant tumors. Studies have shown its role as an important autocrine growth factor for androgen-dependent human prostate cancer in vivo. Serum IL-6 has also been associated with poor prognosis in prostate cancer. We performed a digital analysis of IL-6 immunoreactivity in prostate cancer epithelial cells to determine differences in IL-6 expression between recurrence and non-recurrence groups in a PCa nested case-control cohort. We analyzed an outcome-based TMA obtained from the Cooperative Prostate Cancer Tissue Resource (CPCTR) containing quadruplicate cores (0.6mm core diameter) from 200 pairs of PCa tumor samples (n=400). Cases with PSA recurrence were matched 1:1 with cases without recurrence by race, age, year of surgery, Gleason grade, and pathological stage. All cases had at least five-years follow up. TMA slides were incubated with rabbit polyclonal IL-6 antibody (Abcam) in a 1:600 dilution. Expression levels of IL-6 were assessed by Colocalization Algorithm (ScanScope®, Aperio Corp). Differences in IL-6 intensity between case-control pairs were calculated by Wilcoxon signed rank paired test. Automated data was available for analysis in 149 pairs (n=298). The Wilcoxon signed rank test showed no statistically significant differences in IL-6 intensity between the two groups (p = 0.7). To the best of our knowledge, this is the first study to examine the expression of IL-6 in a large PCa TMA set. Our results revealed IL-6 expression in cancer tissue; however, after statistical analysis, no significant differences were obtained to indicate that IL-6 may be considered as prognostic marker of prostate cancer with biochemical recurrence if cases were first matched by race, age, date of prostatectomy, Gleason score, and stage. In our study we excluded stromal and inflammatory cells IL-6 expression. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1756.

Peroxisome proliferator‐activated receptorsγ (PPARγ) differently modulate the interleukin‐6 expression in the peri‐infarct cortical tissue in the acute and delayed phases of cerebral ischaemia

Interleukin-6 (IL-6) exerts neuroprotective effects after cerebral ischaemia but can also exacerbate inflammation and induce neuronal death. The current study investigates the role of cerebral peroxisome proliferator-activated receptor(s) gamma (PPARgamma) in the regulation of IL-6 expression in the peri-infarct cortical tissue in rats exposed to focal cerebral ischaemia. Pioglitazone, a high-affinity PPARgamma ligand, was infused intracerebroventricularly (i.c.v.) via osmotic minipumps over a 5-day period before, during and 24 h or 48 h after middle cerebral artery occlusion (MCAO) for 90 min followed by reperfusion. The expression of PPARgamma and IL-6 in cortical tissue adjacent to the ischaemic core was studied 24 h and 48 h after MCAO. Pioglitazone augmented the ischaemia-induced upregulation of PPARgamma at both time points. Cerebral ischaemia substantially increased IL-6 expression in the peri-infarct cortical tissue. Twenty-four hours after MCAO, the majority of microglial cells/macrophages showed an intense IL-6 immunoreactivity. IL-6 was also localized in neurons, but the distribution of neurons positively stained for IL-6 at the border of the infarct was very heterogeneous. Pioglitazone effectively decreased the number of IL-6-immunoreactive cells and IL-6 protein levels at 24 h but not at 48 h after MCAO. Pioglitazone treatment reduced the infarct size and improved neurological functions. The present study demonstrates that cerebral PPARgamma suppresses the expression of IL-6 in ischaemic brain tissue during the initial phase of ischaemic stroke, in which the overproduction of IL-6 may aggravate neuronal damage, but not at later time points, when IL-6 promotes neuroprotection and inhibits neuronal death.

Expression and Role of Interleukin-6 in Distraction Osteogenesis

Distraction osteogenesis is a special form of bone healing in which well-controlled distraction stresses and consequent tensile strains within callus tissue induce very efficient new bone formation. Proinflammatory cytokines are involved during the early phase of fracture healing and callus remodeling. Temporal expression patterns of proinflammatory cytokines were assessed in Sprague-Dawley rat tibial models of distraction osteogenesis and acute lengthening, and only interleukin-6 (IL-6) was found to be specifically induced during the distraction phase. IL-6 immunoreactivity was detected not only in hemopoietic cells and osteoblasts but also in the spindle-shaped cells of the fibrous interzone, where most of the tensile strains are concentrated. In vitro study revealed that IL-6 did not affect the proliferation of C3H10T1/2 cells, mouse bone marrow stromal cells (MSCs), or MC3T3-E1 cells; but its blocking antibody reduced the proliferation of C3H10T1/2 cells and MSCs. The mRNA expression of COL1A1 and osteopontin were not changed by IL-6 or its blocking antibody, but the alkaline phosphatase activities of MC3T3-E1 cells were increased by IL-6 and decreased by its blocking antibody. These findings indicate that IL-6 is a proinflammatory cytokine that responds to tensile strain during distraction osteogenesis. IL-6 negatively affects the proliferation of primitive mesenchymal cells, whereas the differentiation of more mature osteoblastic lineage cells is enhanced by IL-6 in vitro. IL-6 appears to be one of the cytokines involved in the complex network of signal cascades evoked during distraction osteogenesis and may differentially affect immature and mature osteoblastic lineage cells.

Interleukin-6 and IL-6 receptor cell expression in testis of rats with autoimmune orchitis

Experimental autoimmune orchitis (EAO) is an organ-specific model of autoimmunity characterized by an interstitial lymphomononuclear cell infiltrate as well as sloughing and apoptosis of germ cells. EAO was induced in adult male Sprague–Dawley rats by active immunization with testicular homogenate and adjuvants. Rats injected with saline solution and adjuvants were used as control group. The aim of this work was to study the expression of interleukin-6 (IL-6) and its receptor (IL-6R) in the testis of rats with EAO and analyze whether IL-6 could be involved in germ cell apoptosis. By immunohistochemistry, we detected IL-6 expression in testicular macrophages and Leydig cells of control and EAO rats. Sertoli cells showed IL-6 immunoreactivity in most of the seminiferous tubules of control rats, while a few IL-6 + Sertoli cells were found in the testis of rats with EAO. IL-6R immunoreactivity was observed in macrophages, Leydig and germ cells. A significant increase was noted in the number of IL-6R + germ cells in rats with EAO compared to control rats. The content of IL-6 (ELISA) in the conditioned media obtained from testicular macrophages of rats with orchitis was significantly higher than in the control group. By immunofluorescence performed on isolated testicular macrophages, IL-6 was shown to be expressed by monocytes recently arrived from circulation (ED1 + cells), while resident macrophages (ED2 + cells) were negative. In vitro experiments (trypan blue and MTS assays) showed that IL-6 (50 ng/ml) reduced germ cell viability. We demonstrated also using the TUNEL technique that IL-6 added to cultures of seminiferous tubule segments induced apoptosis of germ cells. Our results suggest that IL-6 and IL-6R may be involved in the pathogenesis of autoimmune orchitis by promoting testicular inflammation and germ cell apoptosis.

Proinflammatory cytokines expression in noise-induced damaged cochlea

Recent studies have showed that inflammatory responses occur in inner ear under various damaging conditions including noise-overstimulation. We evaluated the time-dependent expression of proinflammatory cytokines in noise-exposed rat cochlea. Among several detected cytokines, real-time RT-PCR showed that interleukin-1beta (IL-1beta) and interleukin-6 (IL-6) were significantly induced 3 hr after noise exposure, and quickly downregulated to the basal level. Tumor necrosis factor-alpha (TNF-alpha) was also slightly upregulated immediately after noise exposure. Immunohistochemical analysis showed that IL-6 expression was distinctively induced within the lateral side of the spiral ligament. Sequential expression analysis showed that IL-6 immunoreactivity was initially found in the cytoplasm of lateral wall cells, including Type IV and III fibrocytes, and expanded broader throughout the lateral wall, finally to the stria vascularis. Because of the negative Iba-1 staining, IL-6 expression in the early-phase was not due to macrophage or microglia activation. IL-6 was also detected in spiral ganglion neurons at 12 and 24 hr after noise exposure. Our data demonstrates the production of proinflammatory cytokines, including TNF-alpha, IL-1beta, and IL-6, in early phase of noise overstimulated cochlea. IL-6 expression was observed in the spiral ligament, stria vascularis, and spiral ganglion neurons. These cytokines, produced by the cochlear structure itself in response to noise exposure, may initiate an inflammatory response and have some role in the mechanism of noise-induced cochlear damage.

Serum Immunosuppressive Acidic Protein as an Interleukin-6 Related Index of Deteriorating Condition in Gastric Cancer Patients

Background/Aims: Immunosuppressive acidic protein (IAP) is an acute-phase reactant which has a close correlation with the impairment of the host’s immunity. The present study aims to investigate the significance of serum IAP as an index of cytokine-related disease status in gastric cancer patients. Methods: Serum IAP levels were determined in 76 gastric cancer patients and 20 healthy subjects. In a subgroup of 39 patients, tissue interleukin-6 (IL-6) concentrations and expression of IL-6 protein in tumor tissues were also examined. Results: The mean serum IAP level in the patients was significantly higher than that in the normal controls. The serum IAP level in the patients was associated with clinicopathological features, such as tumor size and serosal invasion. The prognosis of patients with high IAP levels was significantly worse than that of those with low IAP levels. Moreover, the serum IAP level was closely correlated with various parameters reflecting the host’s nutritional and immunological conditions. Immunohistochemically, IL-6 was overexpressed in the cytoplasm of tumor cells. The IL-6 concentration and immunoreactivity of IL-6 protein in tumor tissue was significantly correlated with the serum IAP level. Conclusions: Elevated serum IAP, which may be upregulated by an activated IL-6 network in tumor tissue, may reflect not only tumor progression, but also a deteriorated condition that is associated with malnutrition and immunosuppression in gastric cancer patients.

Immunohistochemical localization of interleukin-6 in peripheral human endocrine glands.

Interleukin-6 (IL-6) is a pleiotropic cytokine with differentiation and growth-promoting effects. Extensive studies in experimental animals denote that IL-6 is produced in various endocrine organs and participates in the local control of endocrine cell function. The expression of this cytokine in human endocrine glands, however, has only been examined in a limited number of studies. We investigated the immunohistochemical expression and localization of IL-6 in a variety of peripheral human endocrine glands. In the adrenals, IL-6 immunoreactivity was detected in all three zones of the cortex. The reticularis and glomerulosa zones were more heavily stained as compared with the slight immunoreactivity of the fasciculata zone. In the adrenal medulla, chromaffin and sustentacular cells were variably positive. A substantial number of follicular thyroid cells were strongly immunoreactive for IL-6 in all normal and hyperplastic thyroids examined. Parafollicular cells were negative. Parathyroid chief cells were mildly positive; selective and more intense staining was observed in acidophilic cells. Pancreatic islet cells were variably positive. In the testis positive staining was selectively observed in both Leydig and Sertoli cells. In conclusion, IL-6 immunoreactivity is present in almost all the human endocrine glands and it expressed in a cell-specific manner. These observations provide further support for the existence of local immune-endocrine interactions.

Increased interleukin-6 of skin and serum in amyotrophic lateral sclerosis

Studies of skin in amyotrophic lateral sclerosis (ALS) have demonstrated morphological and biochemical alterations. Interleukin-6 (IL-6) has been suggested to have a trophic effect in nerve cells and to have a direct pathogenic role in neurodegenerative central nervous system (CNS) disorders. However, little is known concerning IL-6 in ALS patients. We examined IL-6 immunoreactivity of biopsy specimens of skin and measured serum IL-6 levels from 11 ALS patients and 11 diseased control subjects. IL-6 immunoreactivity was markedly positive in the epidermis and dermal blood vessels and glands and was moderately positive in the reticular dermis in all ALS patients. These optical densities for IL-6 immunoreactivity in ALS patients were significantly higher than in control subjects, and were significantly increased with duration of illness. Serum IL-6 levels were detected in 8 (73%) of 11 ALS patients compared with only 1 (9%) of 11 diseased control subjects. Serum IL-6 levels were significantly correlated with duration of illness in ALS patients and immunoreactivity of IL-6 of the epidermis. These data suggest that the increased levels of serum IL-6 may reflect an increased IL-6 immunoreactivity of skin in ALS patients.

Temporal profile and cellular localization of interleukin-6 protein after focal cerebral ischemia in rats.

Although interleukin-6 (IL-6) has various neuroprotective effects against cerebral ischemia, the topographic distribution and cellular source of IL-6 after cerebral ischemia remain unclear. In the current study, the localization of IL-6 protein was immunohistochemically examined in rats after 3.5, 12, 24, and 48 hours of reperfusion after 1.5 hours of middle cerebral artery occlusion. Middle cerebral artery occlusion was induced by the intraluminal suture method. The specificity of the anti-IL-6 antibody used in the current study was confirmed by Western blot analysis and an immunoabsorption test. To identify the cellular source, lectin histochemical study and immunohistochemical study with microtubule-associated protein-2, ED1, and glial fibrillary acidic protein also were carried out. The sham group did not show any clear IL-6 immunoreactivity. After 3.5 hours of reperfusion, IL-6 immunoreactivity was first detected on the reperfused side, and it was upregulated, especially in the periinfarct region, after 24 hours of reperfusion. Also, IL-6 was expressed after 3.5 hours of reperfusion in the contralateral cerebral cortex and bilateral hippocampi. Double staining showed that the cells containing IL-6 were neurons and round-type microglia, not astrocytes. The current findings suggest that IL-6 expression in ischemically threatened neurons and reactive microglia is closely associated with brain tissue neuroprotective mechanisms against cerebral ischemia.

Microglial and astrocytic involvement in a murine model of Parkinson's disease induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)

We have studied the reaction of glial cells in mice treated with an intraperitoneal administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a selective neurotoxin of dopaminergic nigrostriatal neurons. Signs of injury to the dopaminergic neurons started on the 1st day after MPTP administration and progressed up to the end of the observation time (21st day). A transient microglial reaction was demonstrated from the 1st until the 14th day in the substantia nigra (SN) and striatum. The cells showed an increase in number and changes in morphology. At the ultrastructural level, signs of phagocytosis and features indicating the secretion of biologically active substances were observed. Astrocytosis followed the microglial reaction by one day and was noticed until the end of the observation time. Interleukin-6 immunoreactivity was observed within microglia and astrocytes in the SN on days 2 and 3. There were no signs of depletion of dopaminergic cells or glial activation after the administration of MPTP simultaneously with pargyline, an inhibitor of monoamine oxidase-B that prevents MPTP neurotoxicity. Our study indicates that microglia and astrocytes are involved in the pathological process in the nigrostriatal system following MPTP administration. MPTP alone is not responsible for glial cell activation but its metabolite MPP+ and/or agents released by injured neurons may participate in this process.