Leaky gut and inflammatory biomarkers in a medication overuse headache model in male rats.

Background/aim: Medication overuse is common among chronic migraine patients and nonsteroidal antiinflammatory drugs (NSAIDs) are the most frequently overused drugs. The pathophysiological mechanisms underlying medication overuse headache (MOH) are not completely understood. Intestinal hyperpermeability and leaky gut are reported in patients using NSAIDs. The aim of the study is to investigate the role of leaky gut and inflammation in an MOH model MOH model in male rats. Methods: The study was conducted in male Sprague Dawley rats. There were two experimental groups. The first group was the chronic NSAID group in which the rats received mefenamic acid (n = 8) for four weeks intraperitoneally (ip) and the second group was the vehicle group (n = 8) that received 5% dimethyl sulfoxide+sesame oil (ip) for 4 weeks. We assessed spontaneous pain-like behavior, periorbital mechanical withdrawal thresholds, and anxiety-like behavior using an elevated plus maze test. After behavioral testing, serum levels of occludin and lipopolysaccharide-binding protein (LBP) and brain levels of IL-17, IL-6, and high mobility group box 1 protein (HMGB1) were evaluated with ELISA.Results: Serum LBP and occludin levels and brain IL-17 and HMGB1 levels were significantly elevated in the chronic NSAID group compared to its vehicle (p = 0.006, p = 0.016, p = 0.016 and p = 0.016 respectively) while brain IL-6 levels were comparable (p = 0.67) between the groups. The chronic NSAID group showed pain-like and anxiety-like behavior in behavioral tests. Brain IL-17 level was positively correlated with number of head shakes (r = 0.64, p = 0.045), brain IL-6 level was negatively correlated with periorbital mechanical withdrawal thresholds (r = -0.71, p = 0.049), and serum occludin level was positively correlated with grooming duration (r = 0.73, p = 0.032) in chronic NSAID group. Conclusion: Elevated serum occludin and LBP levels and brain IL-17 and HMGB1 levels indicate a possible role of leaky gut and inflammation in an MOH model in male rats. Additionally, a significant correlation between pain behavior and markers of inflammation and intestinal hyperpermeability, supports the role of inflammation and leaky gut in MOH pathophysiology.

Iron homeostasis is altered in response to hypoxia and hypothermic preconditioning in brain glial cells

Background/aim: Altered iron metabolism is one of the pathophysiological mechanisms occurring during hypoxic injuries in the central nervous system. Proper homeostasis of cellular iron is regulated by iron import, storage, and export proteins that prevent excess iron overload or iron starvation in cells. Therapeutic hypothermia is an approved treatment for hypoxic ischemia in newborns, but the underlying molecular mechanism is still unknown. We studied the effects of hypoxia, preceded with preconditioning, on the iron homeostasis of glial cells, known as a major actor in the inflammatory process during perinatal brain injury. Materials and methods: Primary microglia and astrocytes in culture were exposed to 12 h of hypoxia with or without mild hypothermic preconditioning. The mRNA expression was assessed using qPCR. Iron accumulation was visualized via modified Perl's histochemistry. Cytokine levels in cell cultures were measured using ELISA. Results: Hypothermic preconditioning enhanced microglial viability, which previously was decreased in both cell types due to hypoxia. Hypoxia increased iron accumulation in the mixed glial cells and in ferritin expression in both microglia and astrocytes. Hypotermic preconditioning decreased the elevated ferritin-light chain expression significantly in microglia. Iron importer proteins, DMT1 and TfR1, both increased their mRNA expression after hypoxia, and hypothermic preconditioning continued to support the elevation of DMT1 in both glial cell types. Ferroportin expression increased as a survival factor of the glial cell following hypoxia. Hypothermic preconditioning supported this increase in both cell types and was especially significant in astrocytes. IL-10 levels were prominently increased in cell culture after hypothermic preconditioning. Conclusion: The data suggest that hypothermic preconditioning affects cellular iron homeostasis by regulating the storage and transfer proteins of iron. Regulation of the cellular iron traffic may prevent glial cells from experiencing the detrimental effects of hypoxia-related inflammation.

Behavioral and Neurodevelopmental Effects of Early Interventions in Adult Wistar Rats.

INTRODUCTION: Interventions performed in the early period of life are associated with cognitive and behavioral changes in adulthood. The effects of interventions such as exposure to an early stressful life event or environmental enrichment on cognitive and behavioral development are studied. The aim of this study is to develop a new intervention method, to investigate the effects of early interventions on social interaction, memory anxiety levels and NR2B levels in prefrontal and hippocampus in adulthood. The hypothesis of the study is that exposure to the ambivalent mother will affect the behavioral performance of rats at least as much as one hour apart from the mother in the adult period and cause changes in the prefrontal cortex and hippocampus in the NR2B levels. METHOD: In the study, the Wistar rats were divided into four groups as control group (12), group that remained 15 minutes apart from mother (Mild Stress) (12), group that remained 60 minutes apart from mother (Severe Stress) (14) and ambivalent mother group (13). In adulthood, the social interaction test, elevated plus maze and new object recognition test performances of rats were evaluated. ELISA method was used to evaluate the effect of interventions on the prefrontal cortex and hippocampus NMDA R2B levels. RESULTS: The important findings of the study were that in the new object recognition test, separation from the mother did not affect the recognition memory regardless of gender, while the short-term recognition memory of the females of the ambivalent mothers' group was better than the females in the other groups and the long-term memory performance of the mild stress groups men was better than the man in the other groups. In addition, in the social interaction test, the males of the ambivalent group and the mild stress group showed more aggressive behavior. It was determined that the prefrontal cortex NR2B level was higher in the mild stress and ambivalent mother group compared to the severe stress group, and NR2B level was increased in all intervention groups compared to the control group. CONCLUSION: In contrast to the hypothesis, the results of this study support that the ambivalent mother's group rats are not more adversely affected than the severe group rats and that the model created may be an environmental enrichment model rather than an early stressful life event exposure.

Effect of a chloride channel inhibitor, 5-nitro-2- (3-phenylpropylamino)-benzoate, on endothelin-1 induced vasoconstriction in rabbit basilar artery.

AIM: Endothelin-1 (ET-1) has been implicated in the pathophysiology of cerebral vasospasm. Chloride (Cl-) channels exist in vascular smooth muscle and activation of these channels leads to depolarization and contraction. The aim of the present study was to test the effect of 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB), a Cl- channel antagonist, on the ET-1-induced cerebral vasospasm in rabbit basilar artery and thus investigate the contribution of Cl- channels. MATERIAL AND METHODS: Thirty rabbits were divided into five groups and received intra-arterial injection of isotonic saline (Group I, n=6), ET-1 (group II, n=6), ET-1 plus NPPB (Group III, n=6), dimethylsulfate (DMSO4) (Group IV, n = 6) and NPPB (Group V, n=6). Pre and post injection basilar artery diameters were measured in each group and transmission electron microscopic investigations on basilar arteries were performed. RESULTS: The mean pre-injection and post-injection vessel diameters were 0.8833 mm and 0.7000 mm in ET-1 group, 0.6833 mm and 0.8500 mm in ET-1 + NPPB group. NPPB administered prior to ET-1 injection, prevented the ET-1-induced vasoconstriction. Additionally, NPPB prevents the ET-1 induced changes in vessel wall and neurons in the brain stem. CONCLUSION: The results of this study add further insights to our armamentarium against cerebral vasospasm.

The Effect of Hydrogen Sulphide on Experimental Cerebral Vasospasm.

AIM: Cerebral vasospasm is the primary cause of morbidity and mortality after subarachnoid hemorrhage (SAH). Hydrogen Sulfide (H < sub > 2 < /sub > S), a gaseous neurotransmitter, is produced in many tissues including the central nervous system (CNS). The vasodilatatory effect of H2S has been shown in the CNS; however, its role in cerebral vasospasm has not been investigated before. MATERIAL AND METHODS: The rats were divided into 8 groups: control, SAH, sodium hydrosulphide (NaHS), propargylglycine (PPG), aminooxy acetic acid (AOAA), SAH+NaHS, SAH+PPG, and SAH+AOAA. After establishing experimental SAH, the basilar artery and brain stem were harvested at 24th hours. The diameter and wall thickness of basilar artery were measured. Production of H2S was assessed by showing the activity of cystathionine ?-synthase (CBS) and cystathionine ?-lyase enzymes (CSE). RESULTS: NaHS treatment significantly reduced vasospasm at 24 hours following SAH. This vasodilatatory effect was correlated with the CSE expression in basilar artery. CSE and CBS enzyme expressions were significantly lower in brain stem and basilar artery in PPG and AOAA-treated groups. PPG and AOAA treatments exerted a vasoconstrictive effect in the basilar artery. There were statistically significant differences between NaHS, PPG and AOAA groups, in terms of basilar artery luminal diameter. CONCLUSION: H < sub > 2 < /sub > S may have a therapeutic potential in the treatment of vasospasm with its vasodilatator activity.