<p>The cytokine interleukin-6 (IL-6) mediates a wide range of inflammatory and immune responses. Tumor Necrosis Factor α (TNF-α) has a myriad of pro-inflammatory effects on the skin. In this study, we investigated the localizations and expression levels of IL-6, TNF-α and NF-κB in the skin of <em>Rana dybowskii</em> during the breeding period and pre-hibernation. Histologically, the skin of <em>Rana dybowskii </em>consists of epidermis and dermis. Four kinds of cells were identified in the epidermis during the breeding period and pre-hibernation, while the dermis was composed of homogenous gel, mucous glands and granular glands. IL-6, TNF-α and NF-κB were immunolocalized in the epithelial and glandular cells in both periods. Western blotting showed that IL-6, TNF-α and NF-κB were significantly higher in the pre-hibernation compared to the breeding period. Real-Time PCR revealed that the relative mRNA levels of IL-6 and NB-κB in the pre-hibernation increased significantly compared with the breeding period, while the TNF-α mRNA expression levels were no significant difference between these two periods. These results suggested that IL-6, TNF-α and NF-κB may collectively play important roles in the skin immune system of <em>Rana dybowskii</em> during the breeding period and pre-hibernation.</p>

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The oviduct of Chinese brown frog () expands specifically during prehibernation instead of in the breeding period. In this study, we investigated the expression of leptin receptor (Ob-Rb) in oviduct during the breeding period and prehibernation. Histologically, the oviduct of consists of glandular cells, tubule lumen, and epithelial cells. The oviductal weight and pipe diameter also revealed significant differences, which were higher in prehibernation than that of the breeding period. Ob-Rb was observed in stromal cells of oviductal tissue in both the breeding period and prehibernation. The mean protein and mRNA levels of the Ob-Rb were significantly higher in prehibernation as compared with the breeding period. In addition, oviductal content of leptin was also higher in prehibernation than that of the breeding period. These results suggested that oviduct of might be a target organ of leptin, and leptin may play an autocrine/paracrine role mediated by Ob-Rb in regulating the oviductal hypertrophy during prehibernation.