Comparative analysis of gene expression between renal cortex and papilla in nedaplatin-induced nephrotoxicity in rats.

To elucidate the mechanism of nephrotoxicity caused by anti-neoplastic platinum complex, nedaplatin (NDP), treatment with a particular focus on the renal papillary toxicity, we analysed the gene expression profiles of two renal regions, the cortex (RC) and the papilla (RP) in rat kidneys. Male Wistar rats received a single administration of 10 mg/kg intravenous NDP or vehicle alone (5% xylitol solution) and were sacrificed six days later. The kidneys were dissected into the RC and RP and used for histopathological and microarray analyses. Histopathologically, NDP caused characteristic renal lesions, such as necrosis, single cell necrosis (with TUNEL TdT-mediated dUTP-biotin nick end labelling-positive) and regeneration/hyperplasia of the epithelial cells in both renal regions. Global gene expression analysis revealed that several genes involved in various functional categories were commonly deregulated in both renal regions, such as apoptosis, cell cycle regulation, DNA metabolism, cell migration/adhesion and cytoskeleton organization or genes induced as a perturbation of oxidative status and calcium homeostasis. Comparative analysis of gene expression between RC and RP revealed that genes encoding several subtypes of cytokeratins were identified as being specifically overexpressed in RP by the NDP treatment. Differential expression patterns of these selected genes observed by microarray analysis were further confirmed by quantitative real time RT-PCR and immunohistochemistry, which demonstrated increased expression of cytokeratins (CKs) 14 and 19 at the epithelium covering RP and/or collecting duct epithelium. Overall, the results contribute to understanding the renal molecular events of NDP-induced nephrotoxicity including novel potential biomarker genes encoding CKs 14 and 19 that may serve as indicators of renal papillary toxicity.

Relationship of heat shock protein 25 with reactive macrophages in thioacetamide-induced rat liver injury.

Heat shock protein 25 (Hsp25), which has anti-inflammatory activity, was examined for the relationship of its expression to macrophage appearance in thioacetoamide (TAA)-induced rat acute hepatic lesions. TAA-induced lesions, consisting of hepatocyte coagulation necrosis and reactive macrophages, developed in the centrilobular areas. Macrophages immuno-reacting to ED1 (CD68; exudative macrophages) were mainly seen within the lesions, whereas macrophages reacting to ED2 (CD163; resident macrophages and Kupffer cells), which have abundant cytoplasm, appeared mainly in the periphery of the lesions. Hsp25-immunopositivity was seen in hepatocytes around the lesions in relation to ED1- and ED2-positive macrophages in and around the centrilobular lesions, respectively. Because macrophages appearing in early stages of hepatic lesions produce various pro-inflammatory factors, mRNA expressions of tumor necrosis factor-α (TNF-α), monocyte chemoattractant factor-1 (MCP-1) and osteopontin (OPN) were examined in relation to Hsp25 mRNA expression. Hsp25 mRNA expression generally was correlated with TNF-α, MCP-1 and OPN expressions, suggesting their direct or indirect association with Hsp25 expression. Thus, Hsp25 might have a cytoprotection function against macrophages appearing in hepatic lesions, and factors produced by macrophages in the very early stages of hepatic lesions may influence Hsp25 expression. Hsp25 expression should be useful as an index of anti-inflammatory action for evaluation of hepatotoxicants in vivo.

Morphine, oxycodone, and fentanyl exhibit different analgesic profiles in mouse pain models.

Morphine, oxycodone, and fentanyl are clinically prescribed drugs for the management of severe pain. We investigated whether these opioids possess different efficacy profiles on several types of pain in mouse pain models. When the three opioids were tested in the femur bone cancer model, all of them significantly reversed guarding behavior, whereas the effects on limb-use abnormality and allodynia-like behavior differed among the opioids. Particularly, although oxycodone (5 - 20 mg/kg) and fentanyl (0.2 mg/kg) significantly reversed limb-use abnormality, not even a high dose of morphine (50 mg/kg) could reverse it. When the effects of these opioids were examined in a sciatic nerve ligation (SNL) model of neuropathic pain, oxycodone was the most effective, producing an antinociceptive effect without affecting the withdrawal threshold of sham-treated animals. When the effects of these opioids were examined with the tail-flick test using naive animals, oxycodone, morphine, and fentanyl exhibited antinociceptive effects on thermal nociception. These results show that the three opioids exhibit different efficacy outcomes in multiple pain models and that the efficacy profile of oxycodone does not overlap those of morphine and fentanyl.