Upregulated expression of neuropeptide Y in hypothalamic-pituitary system of rats by chronic dexamethasone administration

To study the effect of adrenal steroids on neuropeptide Y (NPY) synthesis in the hypothalamic-pituitary system, we examined NPY expression in rats treated with dexamethasone (a synthetic glucocorticoid) by in situ hybridization and immunohistochemistry. Rats were injected daily with dexamethasone (0.2mg/100g/day for 10 days, sc) or sesame oil (vehicle control), or non-injected (intact control). Relative staining area for corticotropin-releasing hormone or neurophysin II, a vasopressin carrier protein, was increased in the external zone of the median eminence in vehicle control, but was equivalent to that of intact control in the dexamethasone-injected group. Density of NPY-stained fiber varicosities was drastically increased in the external, but not the internal, zone of dexamethasone-injected group, coinciding with the increased NPY hybridization signal level in the arcuate nucleus. Dual-labeling experiments revealed no colocalization of NPY with hypophysiotropic or other peptides examined in single fibers of the median eminence. In the dexamethasone-injected group, expressions of NPY mRNA and peptide were detectable in a few pituitary cells, with some being corticotropes. These results suggest that NPY plays hormonal roles in the hypothalamic-pituitary-adrenal axis.     

Specific type IV phosphodiesterase inhibitor ameliorates thioacetamide-induced liver injury in rats

BACKGROUND AND AIMS: Rolipram is a specific type IV phosphodiesterase inhibitor that suppresses the activity of immune cells and the production of pro-inflammatory cytokines. In this study, we assessed the effect of rolipram on acute liver injury using thioacetamide (TAA)-induced liver injury in rats as a model. METHODS: Rats were treated with rolipram (0.5-5 mg/kg, intraperitoneally) or vehicle and injected 30 min later with TAA (100 mg/kg, subcutaneously). Serum transaminase concentrations and tumor necrosis factor-alpha (TNF-alpha), interleukin 1beta (IL-1beta) and growth related oncogene/cytokine-induced neutrophil chemoattractant-1 (GRO/CINC-1) levels were measured and livers were examined for microscopic changes. Dose-dependent protection against TAA liver injury was based on transaminase levels and inflammatory cytokine production, and was measured 9 h after TAA when the peak release of cytokines occurred. RESULT: Rolipram suppressed liver injury based on serum aspartate transaminase (AST), alanine transaminase (ALT) and histology and reduced TNF-alpha, IL-1beta and GRO/CINC-1 levels. Rolipram, at doses of 0.5-5 mg/kg, suppressed serum transaminase and TNF-alpha production in a dose-dependent manner, and these effects were significant at doses of 2.5 and 5 mg/kg. CONCLUSION: In our rodent model of acute liver injury, rolipram clearly reduced liver damage and inhibited pro-inflammatory cytokine production. These results suggest that specific type IV phosphodiesterase inhibitors, such as rolipram, have potent hepatoprotective effects that are associated with suppressing inflammatory cytokine production.     

Biological half-lives of zinc and manganese in rat brain

The brains of rats injected intravenously with ⁶⁵ZnCl₂ or ⁵⁴MnCl₂ were subjected to high-resolution autoradiography. The distribution of ⁶⁵Zn and ⁵⁴Mn in each brain region gradually decreased from 6 days to 42 days for ⁶⁵Zn and from 15 days to 60 days for ⁵⁴Mn after the injection. The biological half-lives of Zn in each region studied were in the range of 16–43 days; the longest was observed in the amygdaloid nuclei. The regions where the long biological half-life was observed were consistent with the ones with the high density of Zn-containing neuron terminals reported previously. The biological half-lives of Mn in each region determined were 51–74 days; the longest were those in the hypothalamic nuclei and thalamus.     

Chemotherapy for an esophageal cancer patient undergoing continuous ambulatory peritoneal dialysis for chronic renal failure and measurement of plasma concentration of the drug

We administered chemoradiotherapy consisting of 5-fluorouracil (5-FU) combined with cisplatin, radiation and sequential chemotherapy using nedaplatin for an esophageal cancer patient undergoing continuous ambulatory peritoneal dialysis (CAPD) for chronic renal failure. There are no reports in the literature of chemotherapy for a patient maintained on CAPD. The dosage of each drug was based on that for a patient undergoing hemodialysis, and the plasma concentration of each drug was examined. Chemotherapy consisted of 3-10 mg/body of cisplatin with 60-min infusion and 450 mg/body of 5-FU with continuous infusion over 5 days. There were no side effects and no increase in the concentration of either of the drugs. Subsequently, 50 mg/body of nedaplatin, which is half the dose for a patient with normal renal function, was administered. The area under the blood concentration time curve (AUC) of nedaplatin was 15.85 microg/ml, which was slightly low compared with that after infusion of 80 mg/m2 in patients with normal renal function. Grade 3 leukopenia and thrombocytopenia occurred. As a final result, a partial response was obtained, and the patient was able to eat solid food after treatment. Although chemotherapy consisting of low-doses of cisplatin and 5-FU and a half dose of nedaplatin was administered safely, further study is needed to determine the suitable regimens for a patient maintained on CAPD.     

Auranofin protects against cocaine-induced hepatic injury through induction of heme oxygenase-1

Auranofin, a disease-modifying gold compound, has been empirically applying to the management of rheumatoid arthritis. We investigated a protective effect of auranofin against hepatic injury induced by cocaine. Cocaine (75 mg/kg) markedly increased serum alanine amino transferase (ALT) (4,130 IU/l) and aspartate amino transferase (AST) (1,730 IU/l) activities at 16 hr after treatment, and induced hepatic necrosis surrounding central veins in mice. Concurrently, overexpression of heme oxygenase-1 (HO-1), a rate-limiting enzyme for heme degradation and an oxidative stress marker, was identified at the edges of cocaine-mediated necrotic area. Auranofin (10 mg/ml, i.p.) significantly induced hepatic HO-1 protein in mice from 12 hr after treatment. Interestingly, pretreatment with auranofin resulted in the prevention of the increase of serum ALT and AST activities in a dose-dependent manner. On the other hand, although cocaine increased tumor necrosis factor α (TNFα) gene expression in mouse livers, cocaine-induced liver injury was observed in TNFα deficient mice as well as wild-type mice. Auranofin-inducted HO-1 gene expression was observed in human primary hepatocytes as well as mouse primary hepatocytes. The present findings suggest that auranofin is effective in preventing cocaine-induced hepatic injury, and HO-1 may contribute to protect against chemically-induced cytotoxicity.     

Effect of cilostazol, a selective type-III phosphodiesterase inhibitor, on water-immersion stress-induced gastric mucosal injury in rats

Background Cilostazol, a specific type-III phosphodiesterase inhibitor, is widely used for the treatment of ischemic symptoms of peripheral vascular disease. Recent studies have reported that the mechanism of cilostazol is related to the suppression of pro-inflammatory cytokine production and improvement of local microcirculation disturbances. The pathogenesis of stress-induced gastric mucosal lesions is characterized by the activation of inflammatory cells and the production of inflammatory cytokines. The effects of cilostazol on the development of gastric mucosal lesions have not been reported. In the present study, we examined the effect of a cilostazol on water-immersion stress-induced gastric mucosal lesions. Methods Rats were subjected to water-immersion stress with or without pretreatment with a single intraperitoneal injection of the selective type-III phosphodiesterase inhibitor, cilostazol. We measured the gastric mucosal lesion and the concentrations of myeloperoxidase (MPO), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and cytokine-induced neutrophil chemoattractant-1 (GRO/CINC-1), as an index of neutrophil accumulation and pro-inflammatory cytokine production. Results Cilostazol ameliorated the gastric mucosal injury induced by water-immersion stress (P < 0.001). The gastric contents of MPO, TNF-α, IL-1β, and CRO/CINC-1 were all increased after water-immersion stress and were reduced to almost normal levels by cilostazol. Conclusions In this study, we demonstrated that a selective type-III phosphodiesterase inhibitor, cilostazol, inhibited stress-induced gastric inflammation and damage via suppressing the production of pro-inflammatory cytokines. Cilostazol may be useful for preventing gastric mucosal lesions.     

Selective A2A adenosine agonist ATL-146e attenuates acute lethal liver injury in mice

Background d-Galactosamine (GalN)/lipopolysaccharide (LPS)-induced liver injury is an experimental model of fulminant hepatic failure in which tumor necrosis factor- (TNF-) plays a pivotal role. We examined the effects of a highly selective adenosine A_2A receptor agonist (ATL-146e) on GalN/LPS-induced fulminant hepatic failure.Methods Mice were given an intraperitoneal dose of GalN (800mg/g body weight)/LPS (100ng/g body weight) with and without ATL-146e (0.01µg/kg) treatment. Liver injury was assessed biochemically and histologically. Also, TNF- levels in the serum were determined.Results The serum liver enzyme (ALT) level in vehicle-treated mice was 20960 ± 2800IU/ml and was reduced by 63% to 7800 ± 1670IU/ml by treatment with 0.01µg/kg per minute ATL146e, P < 0.05. Treatment with ATL-146e significantly reduced serum TNF- and greatly reduced inflammation assessed by histopathologic examination compared with control mice treated with GalN/LPS. ATL-146e also reduced lethality at 12h from 65% to 13%.Conclusion The present findings suggest that the highly selective adenosine A_2A receptor agonist (ATL-146e) prevents endotoxin-induced lethal liver injury by suppression of TNF- secretion.     

Rolipram, a Specific Type IV Phosphodiesterase Inhibitor, Ameliorates Aspirin-Induced Gastric Mucosal Injury in Rats

Inhibition of type IV phosphodiesterase (PDE IV) activity reduces the production of various proinflammatory cytokine and suppresses neutrophil activation. Nonsteroidal anti-inflammatory drugs such as aspirin induce gastric mucosal lesions. In the pathogenesis of aspirin-induced gastric mucosal lesion, the contributions, of activated inflammatory cells and proinflammatory cytokine production are critical. The specific PDE IV inhibitor rolipram is known to be a potent inhibitor of inflammation by increasing intracellular cyclic AMP in leukocytes. The aim of the present study was to determine whether rolipram can ameliorate aspirin-induced gastric mucosal lesions in rats and whether the agent can inhibit the inrease in neutrophil accumulation and the production of proinflammatory cytokines. Gastric lesions were produced by administration of aspirin (200 mg/kg) and HCl (0.15 N; 8.0 ml/kg). Rolipram was injected 30 min before aspirin administration. The tissue myeloperoxidase concentration in gastric mucosa was measured as an indicat or of neutrophil infiltration. The gastric mucosal concentrations of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were determined by ELISA. The intragastric administration of aspirin induced multiple hemorrhagic erosions in rat gastric mucosa. Gastric mucosal lesions induced by aspirin were significantly inhibited by treatment with rolipram. The mucosal myeloperoxidase concentration was also suppressed by rolipram. Increases in the gastric content of TNF-α and IL-1β after aspirin administration were inhibited by pretreatment with rolipram. We demonstrated that the specific type IV PDE inhibitor, rolipram, could have a potent antiulcer effect, presumably mediated by its anti-inflammatory properties.