Neurobehavioral impairments in ciprofloxacin-treated osteoarthritic adult rats

Background and purpose – Ciprofloxacin (CIP) is a broad-spectrum antibiotic widely used in clinical practice to treat musculoskeletal infections. Fluoroquinoloneinduced neurotoxic adverse events have been reported in a few case reports, all the preclinical studies on its neuropsychiatric side effects involved only healthy animals. This study firstly investigated the behavioral effects of CIP in an osteoarthritis rat model with joint destruction and pain, which can simulate inflammation-associated musculoskeletal pain. Furthermore, effects of CIP on regional brain-derived neurotrophic factor (BDNF) expression were examined given its major contributions to the neuromodulation and plasticity underlying behavior and cognition. Methods – Fourteen days after induction of chronic osteoarthritis, animals were administered vehicle, 33 mg/kg or 100 mg/kg CIP for five days intraperitoneally. Motor activity, behavioral motivation, and psychomotor learning were examined in a reward-based behavioral test (Ambitus) on Day 4 and sensorimotor gating by the prepulse inhibition test on Day 5. Thereafter, the prolonged BDNF mRNA and protein expression levels were measured in the hippocampus and the prefrontal cortex. Results – CIP dose-dependently reduced both locomotion and reward-motivated exploratory activity, accompanied with impaired learning ability. In contrast, there were no significant differences in startle reflex and sensory gating among treatment groups; however, CIP treatment reduced motor activity of the animals in this test, too. These alterations were associated with reduced BDNF mRNA and protein expression levels in the hippocampus but not the prefrontal cortex. Conclusion – This study revealed the detrimental effects of CIP treatment on locomotor activity and motivation/learning ability during osteoarthritic condition, which might be due to, at least partially, deficient hippocampal BDNF expression and ensuing impairments in neural and synaptic plasticity

Cooperation of aquaporin 5 and the adrenergic system in the initiation of birth in rat model

Aquaporins (AQPs) are involved in the process of implantation, regulate myometrial contractions and cervical ripening, and maintain appropriate placental functioning. The molecular mechanism of these functions is not fully understood. Our study aimed to investigate the physiological significance of AQP5 during pregnancy and to determine the cooperation between the adrenergic system and the AQP5 in uterine contraction in the late-pregnant rat uterus. After administering AQP5 siRNA intraperitoneally to Sprague-Dawley rats, the length of the gestational period was determined and the changes in uterine contractions were measured in an isolated organ bath system. Pharmacological influence on AQP5 expression and uterine contraction was investigated by treatment with terbutaline (10 mg/kg, subcutaneously) and doxazosin (5 mg/kg, orally) in vivo; and mercuric chloride (HgCl2), in vitro. Moreover, the levels of cAMP response element binding protein (CREB) were measured in the uterus by an ELISA kit. The gestational period became shorter, AQP5 expression significantly decreased and rat uterus contraction increased after AQP5 siRNA treatment compared to the control. Treatment with terbutaline significantly increased AQP5 mRNA and protein expression after 30 minutes and continuously reduced it until 90 minutes, whereas doxazosin treatment did not significantly alter AQP5 expression. Treatment with the AQP5 antagonist HgCl2 increased spontaneous uterus contraction and decreased norepinephrine-induced uterus contraction with decreasing AQP5 expression in pregnant rat uterus. Moreover, the tocolytic effect through the adrenergic system was amplified in the presence of an AQP5 antagonist, presumably via the changes in cAMP level. In conclusion, our findings elucidate the collaborative role of aquaporin 5 (AQP5) and adrenergic systems in the regulation of uterine contractions in late-pregnant rats. Our findings suggest this may be a good starting point for developing a new tocolytic therapy

Immunofluorescent Evidence for Nuclear Localization of Aromatase in Astrocytes in the Rat Central Nervous System

Estrogens regulate a variety of neuroendocrine, reproductive and also non-reproductive brain functions. Estradiol biosynthesis in the central nervous system (CNS) is catalyzed by the enzyme aromatase, which is expressed in several brain regions by neurons, astrocytes and microglia. In this study, we performed a complex fluorescent immunocytochemical analysis which revealed that aromatase is colocalized with the nuclear stain in glial fibrillary acidic protein (GFAP) positive astrocytes in cell cultures. Confocal immunofluorescent Z-stack scanning analysis confirmed the colocalization of aromatase with the nuclear DAPI signal. Nuclear aromatase was also detectable in the S100 beta positive astrocyte subpopulation. When the nuclear aromatase signal was present, estrogen receptor alpha was also abundant in the nucleus. Immunostaining of frozen brain tissue sections showed that the nuclear colocalization of the enzyme in GFAP-positive astrocytes is also detectable in the adult rat brain. CD11b/c labelled microglial cells express aromatase, but the immunopositive signal was distributed only in the cytoplasm both in the ramified and amoeboid microglial forms. Immunostaining of rat ovarian tissue sections and human granulosa cells revealed that aromatase was present only in the cytoplasm. This novel observation suggests a new unique mechanism in astrocytes that may regulate certain CNS functions via estradiol production

Az adrenerg mechanizmusok szerepe és jelentősége a terhes patkány cervix és corpus összehangolt működésének szabályozásában = Role and significance of adrenergic mechanisms in the control of aligned function of pregnant rat cervix and corpus

A kutatás célkitűzése az adrenerg hatóanyagok hatásának vizsgálata a terhes patkány cervixen és corpuson. Irodalmi adatok segítségével beállítottunk és továbbfejlesztettünk egy cervix rezisztencia mérő módszert, melynek segítségével kimutattuk, hogy a terbutalin in vitro képes fokozni a cervix nyújtással szembeni rezisztenciáját a terhesség végén (18-22. nap). Igazoltuk, hogy a hatás hátterében az aktivált G-protein mennyiségét csökkentő tulajdonsága játszik szerepet. A corpuson a terbutalin relaxáló hatást fejt ki, mely a terhesség előrehaladtával csökken, ennek oka a G-protein aktiváló hatásának csökkenésében mutatkozik. A terbutalin corpusban mutatott gyengülő hatása progeszteron kezeléssel visszafordítható, melyet a G-protein aktiváció erősödése is kísér. In vivo koraszülés modellben is sikerült igazolnunk a betamimetikumok és a gesztagének közötti potenciáló szinergizmust, mely terápiás jelentőséggel bírhat. Az altípusszelektív α1-adrenerg receptor blokkolóknál kimutattuk, hogy az α1A antagonista WB4101 gátolja az uterusz kontrakciókat és jelentős mértékben fokozza a terhesség végén a cervix rezisztenciát. A többi altípusszelektív antagonista (α1B, α1D) nem volt hatásos e tekintetben. A WB4101 cervix rezisztenciát fokozó hatása magyarázataként G-protein aktiváló hatását találtuk, melynek hátterében a vegyület inverz agonista tulajdonsága áll. Mindezek alapján az α1A antagonisták esetleges tokolitikus alkalmazása további megerősítést nyert. | The principal goal of the study was to investigate the pharmacological effect of adrenergic compounds on the pregnant rat uterus and cervix. On the basis of literature data we have adjusted and further developed an in vitro model to assess cervical resistance, by which method we have demonstrated that terbutaline enhanced cervical resistance by the end of pregnancy (days 18-22). In the background of this effect we have justified that terbutaline decreased G-protein activation in the cervix. Terbutaline relaxes the pregnant uterus, which effect declines towards term, this phenomenon is due to decreased G-protein activation. The decrease in the effect of terbutaline on the uterus can be reversed by the administration of progesterone, which results in enhanced G-protein activation. We have also demonstrated a potentiating synergism between the alpha-adrenergic agonists and progesterone in an in vivo rat preterm birth model, which may have therapeutic benefit in obstetrical practice. The subtype-selective alpha1A-adrenergic receptor antagonist WB 4101 either relaxed the pregnant uterus and increased cervical resistance. Other (alpha1B-, 1D) antagonists were not proved to be effective in neither tissue. The enhanced cervical resistance by WB 4101 was confirmed by its increasing effect on G-protein activation, due to its partial agonist property. Upon these results we have provided further evidence on the possible tocolytic use of alpha1A-adrenergic receptor antagonists

Obesity in pregnancy: a novel concept on the roles of adipokines in uterine contractility

Obesity is a global health problem even among pregnant women. Obesity alters quality of labor, such as preterm labor, prolonged labor, and higher oxytocin requirements in pregnant women. The most important factors to play a role in the altered gestational period and serve as drug targets to treat the consequences are female sexual hormones, calcium channels, adrenergic system, oxytocin, and prostaglandins. However, we have limited information about the impact of obesity on the pregnant uterine contractility and gestation time. Adipose tissue, which is the largest endocrine and paracrine organ, especially in obesity, is responsible for the production of adipokines and various cytokines and chemokines, and there are no reliable data available describing the relation between body mass index, glucose intolerance, and adipokines during pregnancy. Recent data suggest that the dysregulation of leptin, adiponectin, and kisspeptin during pregnancy contributes to gestational diabetes mellitus and pre-eclampsia. A preclinical method for obese pregnancy should be developed to clarify the action of adipokines and assess their impact in obesity. The deeper understanding of the adipokines- induced processes in obese pregnancy may be a step closer to the prevention and therapy of preterm delivery or prolonged pregnancy. Gestational weight gain is one of the factors that could influence the prenatal development, birth weight, and adiposity of newborn

The effects of estrogen on the α2-adrenergic receptor subtypes in rat uterine function in late pregnancy in vitro

Aim To assess the effect of 17β-estradiol pretreatment on the function and expression of α2- adrenergic receptors (ARs) subtypes in late pregnancy in rats. Methods Sprague-Dawley rats (n = 37) were treated with 17β-estradiol for 4 days starting from the 18th day of pregnancy. The myometrial expression of the α2-AR subtypes was determined by real time polymerase chain reaction and Western blot analysis. In vitro contractions were stimulated with (-)-noradrenaline, and its effect was modified with the selective antagonists BRL 44408 (α2A), ARC 239 (α2B/C), and spiroxatrine (α2A). The cyclic adenosine monophosphate (cAMP) accumulation was also measured. The activated G-protein level was investigated by guanosine 5’-O-[gamma-thio]triphosphate (GTPγS) binding assay. Results 17β-estradiol pretreatment decreased the contractile effect of (-)-noradrenaline via the α2-ARs, and abolished the contractile effect via the α2B-ARs. All the α2-AR subtypes’ mRNA was significantly decreased. 17β-estradiol pretreatment significantly increased the myometrial cAMP level in the presence of BRL 44408 (P = 0.001), ARC 239 (P = 0.007), and spiroxatrine (P = 0.045), but did not modify it in the presence of spiroxatrine + BRL 44408 combination (P = 0.073). It also inhibited the G-protein-activating effect of (-)-noradrenaline by 25% in the presence of BRL 44408 + spiroxatrine combination. Conclusions The expression of the α2-AR subtypes is sensitive to 17β-estradiol, which decreases the contractile response of (-)-noradrenaline via the α2B-AR subtype, and might cause changes in G-protein signaling pathway. Estrogen dysregulation may be responsible for preterm labor or uterine inertia via the α2-AR

Immunofluorescent Evidence for Nuclear Localization of Aromatase in Astrocytes in the Rat Central Nervous System

Estrogens regulate a variety of neuroendocrine, reproductive and also non-reproductive brain functions. Estradiol biosynthesis in the central nervous system (CNS) is catalyzed by the enzyme aromatase, which is expressed in several brain regions by neurons, astrocytes and microglia. In this study, we performed a complex fluorescent immunocytochemical analysis which revealed that aromatase is colocalized with the nuclear stain in glial fibrillary acidic protein (GFAP) positive astrocytes in cell cultures. Confocal immunofluorescent Z-stack scanning analysis confirmed the colocalization of aromatase with the nuclear DAPI signal. Nuclear aromatase was also detectable in the S100 beta positive astrocyte subpopulation. When the nuclear aromatase signal was present, estrogen receptor alpha was also abundant in the nucleus. Immunostaining of frozen brain tissue sections showed that the nuclear colocalization of the enzyme in GFAP-positive astrocytes is also detectable in the adult rat brain. CD11b/c labelled microglial cells express aromatase, but the immunopositive signal was distributed only in the cytoplasm both in the ramified and amoeboid microglial forms. Immunostaining of rat ovarian tissue sections and human granulosa cells revealed that aromatase was present only in the cytoplasm. This novel observation suggests a new unique mechanism in astrocytes that may regulate certain CNS functions via estradiol production