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Background: The combined effects of metformin and epigallocatechin-3-gallate (EGCG) on cortisol, 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1), and blood glucose levels have not been investigated. This study evaluated the effectiveness of combining EGCG with metformin in regulating those levels in a rat model of diet-induced diabetes and obesity. Methods: Thirty diabetic and obese rats on a high-fat diet were treated daily for 28 days with EGCG (100 mg/kg of body weight/day), metformin (200 mg/kg of body weight/day), or both. Control groups comprised lean rats, untreated obese diabetic rats, and metformin-only-treated rats. Blood samples were collected to measure cortisol and fasting blood glucose (FBG) levels and liver tissue samples were examined for 11ß-HSD1 levels. Results: Rats receiving combination therapy had significantly reduced cortisol levels (from 36.70±15.13 to 31.25±7.10 ng/mL) compared with the untreated obese diabetic rats but not the rats receiving monotherapy. Rats receiving combination therapy and EGCG monotherapy had significantly lower 11ß-HSD1 levels compared with the untreated obese diabetic rats (92.68±10.82 and 93.74±18.11 ng/L vs. 120.66±14.00 ng/L). Combination therapy and metformin monotherapy significantly reduced FBG levels (440.83±133.3 to 140.50±7.36 mg/dL and 480.67±86.32 to 214.17±102.78 mg/dL, respectively) by approximately 68.1% and 55.4% compared with rats receiving EGCG monotherapy and untreated obese diabetic rats. Conclusion: Combining EGCG with metformin exhibited synergistic effects compared with monotherapy for managing diabetes, leading to improved outcomes in reduction of baseline cortisol levels along with reduction in 11ß-HSD1 and blood glucose levels.
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BACKGROUND: Familial Pancreatic Cancer (FPC) presents a notable risk, with 3-10% of pancreatic adenocarcinoma cases having a family history. Studies link FPC to syndromes like HBOC, suggesting BRCA1/BRCA2 mutations play a role. BRCA gene functions in DNA repair impact FPC management, influencing sensitivity to therapies like PARP inhibitors. Identifying mutations not only aids FPC treatment but also reveals broader cancer risks. However, challenges persist in selectively applying genetic testing due to cost constraints. This Systematic Review focuses on BRCA1/BRCA2 significance in FPC, diagnostic criteria, prognostic value, and limitations. METHOD: Original articles published from 2013 to January 2023 were sourced from databases such as Scopus, PubMed, ProQuest, and ScienceDirect. Inclusion criteria comprised observational cohort or diagnostic studies related to the role of BRCA1/2 mutation in correlation to familial pancreatic cancer (FPC), while article reviews, narrative reviews, and non-relevant content were excluded. The assessment of bias used ROBINS-I, and the results were organized using PICOS criteria in a Google spreadsheet table. The systematic review adhered to the PRISMA 2020 checklist. RESULT: We analyzed 9 diagnostic studies encompassing 1325 families and 4267 patients from Italy, USA, and Poland. Despite the limitation of limited homogenous PICO studies, our findings effectively present evidence. BRCA1/2 demonstrates benefits in detecting first-degree relatives FPC involvement with 2.26-10 times higher risk. These mutation findings also play an important role since with the BRCA1/2 targeted therapy, Poly-ADP Ribose Polymerase inhibitors (PARP) may give better outcomes of FPC treatment. Analysis of BRCA1 and BRCA2 administration's impact on odds ratio (OR) based on six and five studies respectively. BRCA1 exhibited non-significant effects (OR = 1.26, P = 0.51), while BRCA2 showed significance (OR = 1.68, P = 0.04). No heterogeneity observed, indicating consistent results. Further research on BRCA1 is warranted. CONCLUSION: Detecting the BRCA1/2 mutation gene offers numerous advantages, particularly in its correlation with FPC. For diagnostic and prognostic purposes, testing is strongly recommended for first-degree relatives, who face a significantly higher risk (2.26-10 times) of being affected. Additionally, FPC patients with identified BRCA1/2 mutations exhibit a more favorable prognosis compared to the non-mutated population. This is attributed to the availability of targeted BRCA1/2 therapy, which maximizes treatment outcomes.
Subject(s)
BRCA1 Protein , BRCA2 Protein , Germ-Line Mutation , Pancreatic Neoplasms , Humans , Pancreatic Neoplasms/genetics , BRCA2 Protein/genetics , BRCA1 Protein/genetics , Genetic Predisposition to Disease , CarcinomaABSTRACT
The GSTT1 and GSTM1 genes have a role in mercury metabolism and excretion, as well as blood pressure response, impacting birth outcomes. The present study assesses whether GSTT1 and GSTM1 deletion variants and maternal hair Hg concentration are associated with blood pressure and birth outcomes among the Indonesian coastal pregnant mother population. A cross-sectional study was conducted on 139 pregnant women in the Jepara coastal area of Central Java, Indonesia. Maternal characteristics during pregnancy, including blood pressure and birth outcomes, were collected. GSTT1 and GSTM1 gene variants were detected using polymerase chain reaction (PCR). Hair Hg levels were measured using the reducing-vaporization mercury analyzer. The mean maternal hair Hg concentration was 0.727±0.558⯵g/g. GSTT1 genotype homozygous deletion was found in 41.7% of subjects, while no GSTM1 deletion was found. No statistically significant difference was found between deletion and non-deletion groups for hair Hg. GSTT1 deletion genotype shows protection but is inconclusive toward diastolic hypertension (p=0.048, OR 0.285, CI 0.077-1.052) and insignificant with birth outcomes (all p>0.05). High hair Hg concentration and positive history of cardiovascular diseases increase the risk of systolic and diastolic hypertension during pregnancy with OR 6.871 (CI 95% 1.445-32.660) and 8.518 (CI 95% 2.126-34.125), respectively, while not in birth outcomes. Maternal Hg exposure and history of cardiovascular diseases are independent risk factors for pregnant hypertension, whereas the GSTT1 homozygous deletion genotype has no role in diastolic hypertension and birth outcomes among the Indonesian coastal pregnant mother population.
Subject(s)
Cardiovascular Diseases , Hypertension , Mercury , Humans , Female , Pregnancy , Indonesia/epidemiology , Pregnant Women , Homozygote , Blood Pressure , Cross-Sectional Studies , Polymorphism, Genetic , Sequence Deletion , Genotype , Glutathione Transferase/genetics , Glutathione Transferase/metabolism , Hypertension/genetics , Hair , Genetic Predisposition to Disease , Case-Control StudiesABSTRACT
Background: Bovine hydroxyapatite (HA) used for bone grafts is relatively expensive, necessitating the development of alternative sources. Alternative HA materials derived from green mussel shells with smaller molecular sizes are inexpensive and abundantly available throughout Indonesian waters. The purpose of this study is to investigate the effect of green mussel shells HA on bone healing. Methods: This post-test-only experimental research used male rabbits with femoral defects divided into three groups randomly: K (no treatment), P1 (bovine HA treatment), and P2 (green mussel shell HA treatment). The osteocalcin level was assessed biochemically while osteoblast cells were histopathologically at the second, fourth, and sixth weeks. Statistic tests were used to assess differences between groups and periods with statistical significance P<0.05. Results: Nine rabbits in each group showed significant differences between groups K, P1, and P2 in term osteocalcin levels at week 2 (2.60, 4.53±0.12, 4.47±0.23; P=0.046), week 4 (5.13±0.12, 8.53±0.12, 7.47±0.12; P=0.025), and week 6 (8.20, 11.93±0.23, 10.93±0.31, P=0.023), while in term osteoblast cells only at week 6 (16.33±3.46, 26.10±3.52, 30.40±3.29; P=0.006). The osteocalcin level and osteoblast increased significantly between groups K and P1/P2 from the initial trial until the last week. Osteoblast cells in the groups P1/P2 increased significantly, especially at week 6. Conclusion: Green mussel shell HA has the biochemical effectiveness of osteocalcin and can increase osteoblast cells comparable to bovine HA, which can enhance bone healing.
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During the last decade, there has been an increase in exposure to heavy metals that can affect human health and the environment, especially mercury (Hg) and cadmium (Cd). These exposures can pollute the rivers or oceans, then contaminating marine organisms. Humans as the last consumer of this food chain cycle can be a place for the bioaccumulation of Hg and Cd, especially for people living in coastal areas, including pregnant women. Exposure to heavy metals Hg and Cd can have a high risk of triggering blood vessel disorders, penetrating the blood-brain barrier (BBB) and the placental barrier, one of which can increase the risk of preeclampsia. Several immunological biomarkers such as some cytokines associated with Hg and Cd exposure are also involved in the pathophysiology of preeclampsia, which are the placental implantation process and endothelial dysfunction in pregnant women. Therefore, countries that have a high incidence of preeclampsia should be aware of the environmental factors, especially heavy metal pollution such as Hg and Cd.
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Bruguiera gymnorhiza (BG) has potential as a functional food because of its dietary fibre content and bioactive components such as flavonoids and phenolic compounds. However, it is not studied in the context of diet-related disease prevention. In the present study, we aimed to investigate the effects of Bruguiera gymnorhiza fruit flour (BGF) on satiety hormone, lipid profile, systemic inflammation, body weight, and caecum SCFA levels in diet-induced obese rats. A total of 28 obese male Wistar rats were divided into four groups. Group 1 (K1) was given a standard chow, group 2 (K2) standard chow + orlistat, group 3 (P1) standard chow + BGF 2 g/200 g BW/day, and group 4 (P2) standard chow + BGF 4 g/200 g BW/day for 28 days. The levels of GLP-1, PYY, total cholesterol (TC), triglyceride (TG), HDL, IL-6, TNF-α, and body weight were measured before and after the intervention; meanwhile, the caecum SCFA levels were assessed only after the intervention. In this study, BGF intervention increased the dose-dependent plasma GLP-1 and PYY levels (P < 0.000). In addition, BGF intervention also decreased lipid profiles (TC & TG) (P < 0.000, respectively) and systemic inflammation in a dose-dependent manner. Finally, acetate, propionate, and total SCFA concentrations were higher in the BGF intervention group (P2) compared to the other groups (p < 0.05). The SCFA levels were associated with satiety hormones, lipids, and systemic inflammation (P < 0.05). The BGF intervention improved satiety hormone, lipid profile, systemic inflammation, and SCFA levels.
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(1) Background: Methylmercury (MeHg) exposure during pregnancy is an important issue due to its possible adverse health effects on fetus. To contribute the development of assessment system of Hg exposure through fish consumption and health effects on children, we examined the hair Hg levels in pregnant women and birth weight and length. (2) Methods: In 2018, a cohort study was conducted on 118 pregnant women-infant pairs from six community health centers in the northern coastal area in Central Java Indonesia. Data on mothers' characteristics during pregnancy, birth outcomes, and fish consumption were collected. Total Hg concentrations were determined from hair samples. (3) Results: The median (min-max) of the maternal hair Hg level was 0.434 (0.146-8.105) µg/g. Pregnant women living in lowland areas, near the sea, showed higher hair Hg concentration and fish consumption than those in highland areas {[0.465 (0.146-8.105) vs. 0.385 (0.150-1.956) µg/g; p = 0.043] and [(85.71 (0-500.0) vs. 49.76 (0.0-428.57) g/day; p < 0.01], respectively}. The maternal hair Hg level had no association with baby's birth weight and length. (4) Conclusions: The median maternal hair Hg is at a low level and had no association with infant birth weight and length in this study subjects.
Subject(s)
Mercury , Methylmercury Compounds , Animals , Birth Weight , Cohort Studies , Female , Fishes , Food Contamination , Hair/chemistry , Humans , Indonesia , Mercury/analysis , Methylmercury Compounds/analysis , Pregnancy , Pregnant WomenABSTRACT
Ciprofloxacin (CIP) has been listed in the last version of the surface water due to its ability to kill human cells by inhibiting the activity of DNA topoisomerase IV. Thus, CIP, along with other antibiotic pollution has become a serious threat to the environment and public health. Ozonation has been used as an advanced technique that is applied in wastewater treatment to remove CIP, but the primary limitation of this method is the low solubility of ozone in water. This study is the first report of CIP removal in a scale-up of its aqueous solution using a self-developed aerator pump-enhanced ozonation (APO) system, which only employs a propeller and a zigzag arrangement of meshes. This aerator pump decreased the size of ozone bubbles by 90% and increased the effective ozone solubility to 0.47 ppm. The mechanism of degradation of CIP is attributed to an oxidation reaction of the antibiotic with reactive oxygen species, such as hydroxyl, oxygen, and hydroperoxyl radicals, generated on the surface of the ozone microbubbles. It was found that the rate and efficiency of degradation of CIP using the APO system were 3.64 × 10-3/min and 83.5%, respectively, which is higher compared with those of conventional flow ozonation (FO) systems (1.47 × 10-3/min and 60.9%). The higher degradation efficiency of CIP by the APO system was also revealed by its higher electrical energy efficiency (0.146 g/kWh), compared to that of the FO system (0.106 g/kWh). The degradation of CIP was also monitored by the resulting antibacterial activity against Escherichia coli and Staphylococcus aureus.
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BACKGROUND: Peritonitis is the second most common cause of severe sepsis that associated with a significant mortality rate. Due to a large gap of newer antibiotics innovation and antibiotic resistance emergence, the use of antioxidant has a possible alternative as adjuvant therapy in peritonitis management. It has been studied that glutathione as an alternative in the development of new anti-inflammatory effect. Thus, the aim of this study was to evaluate the levels of TNF-α and IL-10 after glutathione administration as adjuvant therapy in rat peritonitis model. MATERIALS AND METHODS: Male wistar rats were divided into four groups (n = 6 per group), Group 1: control group (C), Group 2: peritonitis group (P), Group 3: peritonitis + Ceftriaxone group (P + Cef), Group 4: peritonitis + Ceftriaxone + Glutathione group (P + Cef + Glu). Twenty-four hours after peritonitis induction, the blood samples were taken to evaluate TNF-α and IL-10 levels. RESULTS: There was a significantly increase of mean TNF-α level in group 2 (P) 473,86 ± 388,99 pg/ml (p value 0,00) and significantly decrease of mean TNF-α level after glutathione injection in group 4 (P + Cef + Glu) (p value 0,02). No significant changes in IL-10 levels in rats peritonitis model. CONCLUSIONS: Glutathione supplementation is significantly decrease the mean level of TNF-α in rats induced peritonitis, however there is no difference compare to antibiotic only. Moreover, there no significant changes level of IL-10 in rats induced peritonitis after glutathione injection.
ABSTRACT
Type 2 diabetes mellitus (T2DM) is an age-related disease associated with cerebral inflammation and Alzheimer's disease. Garcinia mangostana pericarp (GMP) possesses antihyperglycemic, antidiabetic and anti-inflammatory effects. The aim of the present study was to evaluate the effect of GMP extract on cerebral inflammation in Wistar rats with T2DM by examining the expression levels of glial nuclear factor-κB (NF-κB), interleukin (IL)-6, tumor necrosis factor-α (TNF-α) and superoxide dismutase (SOD). A total of 36 8-10-week-old male Wistar rats were randomly divided into six groups and provided a standard diet (normal control; C1), high-fat diet (HFD) with 200 g/kg GMP extract BW/day (GMP control; C2), HFD with streptozotocin-nicotinamide (diabetic control; C3), and HFD with 100 (M1), 200 (M2) or 400 g/kg body weight (BW)/day (M3) GMP extract for Wistar rats with diabetes. GMP extract was administered for 8 weeks after induction of T2DM was confirmed. Glial NF-κB activity was assessed by immunohistochemical staining, and by measuring IL-6 levels, TNF-α levels and SOD activity in the serum using ELISA. BW significantly increased following HFD treatment. After 7 weeks, the BW remained significantly higher compared with the normal control and GMP extract-treated groups, but decreased continuously in the T2DM groups. Glial NF-κB immunoreaction in the hippocampal region was significantly higher in the diabetic Wistar rats compared with the normal control Wistar rats, and 200 g/kg BW/day GMP significantly reduced its activity. The T2DM Wistar rats showed significantly higher expression levels of serum IL-6 and TNF-α and lower activity of SOD compared with the normal control Wistar rats. Meanwhile, rats in GMP groups M1, M2 and M3 exhibited significant reductions in the levels of IL-6 and TNF-α expression, and increases in SOD activity. GMP extract treatment effectively reduced hippocampal NF-κB, IL-6 and TNF-α levels and increased antioxidant SOD activity. These results suggest that GMP extract prevents cerebral inflammation in T2DM Wistar rats.
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OBJECTIVE: This study aimed to examine the effectiveness of ozonated Aloe vera oil on the wound healing response of full-thickness defect tissue in Sprague-Dawley rats, assessed by collagen thickness and the number of fibroblasts. METHODS: This was an experimental research method using control groups and treatment groups with a posttest only control group design. The results showed that collagen thickness in wounds tended to increase, assessed on day 3 and day 7 using Masson's trichrome staining and microscopic evaluation. RESULTS: There was a significant difference in the number of fibroblasts between the two control and treatment groups on days 3 and 7 tested using one-way Kruskal-Wallis test, with a value of p=0.001(p < 0.05), resulting in a significant difference in wound size reduction between the groups. Further post hoc analysis using the Mann-Whitney test indicated a significant difference between the control groups and the treatment groups (P0, P1 versus P3, P4, P5, P8, P9, and P10) with a value of p=0.009(p < 0.05). CONCLUSIONS: Ozonated Aloe vera oil is effective in increasing the healing response of full-thickness defects, leading to the increase in the number of fibroblasts and collagen thickening that in turn accelerates wound healing in Sprague-Dawley rats.
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The exposure of methylmercury (MeHg) has become a public health concern because of its neurotoxic effect. Various neurological symptoms were detected in Minamata disease patients, who got intoxicated by MeHg, including paresthesia, ataxia, gait disturbance, sensory disturbances, tremors, visual, and hearing impairments, indicating that MeHg could pass the blood-brain barrier (BBB) and cause impairment of neurons and other brain cells. Previous studies have reported some expected mechanisms of MeHg-induced neurotoxicity including the neuroinflammation pathway. It was characterized by the up-regulation of numerous pro-inflammatory cytokines expression. Therefore, the use of anti-inflammatories such as N-acetyl-l-cysteine (NAC) may act as a preventive compound to protect the brain from MeHg harmful effects. This mini-review will explain detailed information on MeHg-induced pro-inflammatory cytokines activation as well as possible preventive strategies using anti-inflammation NAC to protect brain cells, particularly in in vivo and in vitro studies.
Subject(s)
Acetylcysteine/pharmacology , Anti-Inflammatory Agents/pharmacology , Cytokines/metabolism , Inflammation/prevention & control , Methylmercury Compounds/adverse effects , Animals , Brain , Humans , Inflammation/chemically induced , Mice , RatsABSTRACT
Methylmercury (MeHg) is a well-known neurotoxin of the central nervous system (CNS). Neuroinflammation is one of the main pathways of MeHg-induced CNS impairment. This study aims to investigate the expressions of IL-6, MIP-2, and MCP-5, as biomarkers in relation with MeHg-induced CNS impairment and N-acetyl-L-cysteine (NAC) treatment in mice, as well as histopathological changes of brain tissue and clinical symptom such as ataxia. Twenty male Balb/c mice, aged 8-9 weeks, were divided into 4 groups and treated with saline (control), NAC [150 mg/kg body weight (BW) day], MeHg (4 mg Hg/kg BW), or a combination of MeHg and NAC for 17 days. MeHg induced the expression of IL-6, MIP-2, and MCP-5 in the serum, with median values (those in controls) of 55.06 (9.44), 15.94 (9.30), and 458.91 (239.91) mg/dl, respectively, and a statistical significance was observed only in IL-6 expression (p < 0.05). MIP-2 and MCP-5 expressions tended to increase in the cerebrum of MeHg-treated group compared with controls; however, the difference was not statistically significant. MeHg treatment also increased IL-6 expression in the cerebellum (7.73 and 4.81 mg/dl in MeHg-treated group and controls, respectively), with a marginal significance. NAC significantly suppressed MeHg-induced IL-6 and MIP-2 expressions in the serum (p < 0.05 for both), and slightly reduced MCP-5 expression in the cerebrum. Ataxia was observed in all MeHg-treated mice after 9-day exposure as well as the decrease of intact Purkinje cells in brain tissue (p < 0.05). These findings suggest that MeHg induced neurotoxicity by elevating the expression of IL-6, MIP-2, and MCP-5 and causing ataxia symptoms, and NAC reduced MeHg-mediated effects on the CNS.
Subject(s)
Acetylcysteine/therapeutic use , Chemokine CXCL2/biosynthesis , Methylmercury Compounds/toxicity , Monocyte Chemoattractant Proteins/biosynthesis , Neurotoxicity Syndromes/drug therapy , Neurotoxicity Syndromes/metabolism , Acetylcysteine/pharmacology , Animals , Brain/drug effects , Brain/metabolism , Chemokine CXCL2/genetics , Gene Expression , Male , Mice , Mice, Inbred BALB C , Monocyte Chemoattractant Proteins/genetics , Random AllocationABSTRACT
Macrophages play an important role in neurotoxicity caused by methylmercury exposure through inflammatory responses. Methylmercury is known to demethylate to inorganic mercury in the brain, and macrophages are likely to be involved in this process. However, the inflammatory responses of macrophages against exposure to inorganic mercury are unclear. In the present study, inflammatory cytokine expression profiles were examined in the presence of non-toxic doses of inorganic mercury (Hg2+) using RAW264.7 macrophages, focusing on the expression of C-X-C motif chemokine 2 (MIP-2)/platelet-derived growth factor-inducible protein KC (KC) and C-C motif chemokine 12 (MCP-5). Furthermore, the suppressive effect of N-acetyl-L-cysteine (NAC) on inorganic mercury-induced MIP-2 expression was also examined. Inorganic mercury-induced mRNA expression was measured using reverse transcription-quantitative PCR. The mRNA expression of MIP-2 and MCP-5 was significantly upregulated by exposure to 20 µM Hg2+ (non-toxic levels), but not that of KC. The suppressive effect of NAC on these cytokine expression levels was examined by its addition to the culture medium together with Hg2+ (co-treatment), and pre- and post-treatments in which the cells were treated with NAC before and after Hg2+ exposure, respectively. Hg2+-upregulated MIP-2 expression was suppressed by NAC regardless of the time sequence of the treatment, suggesting that the suppressive role of NAC in Hg2+-induced inflammation manifests as a possible chelator and antioxidant/reactive oxygen species scavenger.
ABSTRACT
BACKGROUND: The aim of this study is to examine the inflammatory-cytokine expressions in the presence of non-cytotoxic dose of methylmercury (MeHg) in murine macrophages, which is suspected to play an important role in brain damage caused by MeHg exposure. We focused on murine macrophage inflammatory protein-2 (MIP-2), keratinocyte chemoattractant (KC), and monocyte chemoattractant protein-5 (MCP-5). MIP-2 and KC are murine functional homologues of human IL-8 and MCP-5 for human MCP-1. Furthermore, we examined the suppressive effect of N-acetyl-L-cysteine (NAC) on the MeHg-induced inflammatory cytokines. METHODS: In a murine RAW264.7 macrophage cell line, MeHg-induced cytokine expressions were measured using real-time PCR. The suppressive effect of NAC was examined by putting it into the culture medium together with MeHg (co-treatment). In addition, pre- and post-treatment experiments were conducted, in which the cells were treated with NAC before and after MeHg exposure, respectively. RESULTS: Exposure to a non-cytotoxic dose of MeHg up-regulated the mRNA expression of MIP-2 and MCP-5. On the other hand, KC expression was not induced in the presence of MeHg. Effect of MeHg on MIP-2 expressions was suppressed by pre-, co-, and post-treatment with NAC. However, the suppressive effect of pre-treatment was less than the post-treatment, which was as effective as co-treatment. CONCLUSION: In functional homologues of human IL-8, only MIP-2 expression, not KC, was activated in the presence of non-cytotoxic dose of MeHg in murine RAW264.7 macrophage cell line. The more evident inhibitory effect of NAC observed in post-treatment experiments suggests a possible involvement of intracellular activities such as antioxidant effects.
Subject(s)
Acetylcysteine/pharmacology , Chemokine CXCL2/biosynthesis , Macrophages/drug effects , Methylmercury Compounds/toxicity , Animals , Cytokines/biosynthesis , Macrophages/immunology , Mice , RAW 264.7 CellsABSTRACT
The accumulation of macrophages has been observed around lesions of the brain in patients with Minamata disease. In this condition, mercury has been detected histochemically in macrophages throughout the brain. However, the role of macrophages in the neurotoxicity of methylmercury (MeHg) and the molecular mechanisms of their response to MeHg exposure remain to be elucidated. Here, we investigated how MeHg affects the expression of proinflammatory cytokines such as interleukin (IL)-6 and IL-8 in cultured human U937 macrophages. Compared with controls, IL-6 and IL-8 mRNA expression was maximally induced in U937 macrophages after treatment with 10 µM MeHg for 6 h. The protein secretion of IL-6 and IL-8 was significantly stimulated by MeHg in U937 macrophages. Results from luciferase reporter assay indicated functional activation of nuclear factor kappa B and the involvement of subunit RelA and p50 in MeHg-induced IL-6 and IL-8 activation, which was confirmed by siRNA knockdown experiments. MeHg exposure at 4 µM also significantly induced IL-8 expression in U-87 MG cells at mRNA and protein level, indicating that IL-8 induction might be a general mode of action of MeHg treatment among different cell types. These results indicate a possible involvement of an early inflammatory response, including IL-6 and IL-8 expression in the pathogenesis of MeHg. N-acetyl-l-cysteine suppressed MeHg-induced activation of IL-6 and IL-8 mRNA expression in U937 macrophages, indicating the effectiveness of N-acetyl-l-cysteine as a therapeutic drug in MeHg-induced inflammation. Copyright © 2016 John Wiley & Sons, Ltd.
Subject(s)
Interleukin-6/biosynthesis , Interleukin-8/biosynthesis , Macrophages/drug effects , Methylmercury Compounds/toxicity , NF-kappa B p50 Subunit/metabolism , Transcription Factor RelA/metabolism , Acetylcysteine/pharmacology , Cell Survival/drug effects , Free Radical Scavengers/pharmacology , Gene Knockdown Techniques , Humans , Interleukin-6/genetics , Interleukin-8/genetics , Methylmercury Compounds/antagonists & inhibitors , NF-E2-Related Factor 2/biosynthesis , NF-E2-Related Factor 2/genetics , NF-kappa B p50 Subunit/genetics , Transcription Factor RelA/genetics , U937 CellsABSTRACT
AIMS: The aim of this study was to clarify the involvement of oxidative stress in methylmercury (MeHg)-induced pro-inflammatory cytokine expressions and the suppressive effects of N-acetylcysteine (NAC) in MeHg-induced cytokine expression. MATERIALS AND METHODS: Using U-87-MG human astrocytoma cell line, interleukin (IL)-6 and monocyte chemoattractant protein (MCP)-1 expressions induced by 4 µM MeHg were measured at mRNA and protein levels. Hydrogen peroxide (H2O2) and superoxide anion (O2(-)) were quantified by flow-cytometry analysis. To examine the suppressive effects of NAC on the cytokine expressions among different timing of NAC treatment, cells were treated with 0.5 or 5mM NAC before, simultaneously, or after MeHg administration. KEY FINDINGS: MeHg exposure at 4 µM, a non-cytotoxic concentration, significantly induced MCP-1 and IL-6 expressions at both mRNA and protein levels. A significant increase of H2O2 production but not O2(-) was observed. MeHg-induced expression of MCP-1 and IL-6 mRNA was reduced by 10-20% in the presence of 5mM NAC (co-treatment experiment) compared to cells treated with MeHg only. Pre-treatment of cells with 0.5 or 5mM NAC at 0.5 or 1h and its subsequent washout before MeHg addition suppressed MCP-1 and IL-6 cytokine expressions. Post-treatment of cells with NAC after MeHg addition also suppressed the cytokine induction, but the magnitude of suppression was evidently lower than in co-treated cells even though the H2O2 generation was almost completely suppressed by NAC. SIGNIFICANCE: NAC may effectively suppress the MeHg-induced cytokine production through both, inhibition of reactive oxygen species as well as extracellular chelation of MeHg in astrocytes.