Background: Diabetic patients are refractory to allergic inflammatory diseases. In this study, the influence of alloxan-induced diabetes on allergic skin inflammation was investigated. Methods: Diabetes was induced by intravenous injection of alloxan into male Wistar rats, and the analyses were performed 21 days later. Animals were actively sensitized with a mixture of aluminium hydroxide plus ovalbumin and challenged intradermally with ovalbumin on day 14. Results: Diabetic sensitized rats exhibited a less pronounced antigen-induced protein extravasation in the dorsal skin when compared with normal animals. Also, fragments of the dorsal subcutaneous tissue from diabetic sensitized rats showed a reduction in histamine release after stimulation with antigen in vitrowhen compared with fragments obtained from nondiabetic sensitized rats. Optical microscopy analysis revealed that the dorsal skin of diabetic rats showed a marked reduction in dermis thickness, as compared with that seen in normal animals. A significant decrease in the number of skin mast cells was also noted, a phenomenon that paralleled with the reduction in the expression of extracellular matrix components laminin, fibronectin and collagen. Administration of insulin into diabetic rats restored basal mast cell numbers as well as the levels of laminin, fibronectin and collagen. Conclusions: Our findings show that alloxan diabetes induces downregulation of the skin allergic inflammatory response in rats, and this was correlated with reduction in local mast cell numbers and expression of extracellular matrix components. Lastly, these alterations were reversed with insulin treatment.

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Hypericum perforatum (HP) is well-known by the population of the world as herb with antidepressant effect. Its various components, such as hypericin and hyperforin, provide many other effects for this plant, for example, antinociceptive and anticonvulsant. The aim of this work was to determine whether HP administration during pregnancy can cause changes in neurodevelopment related to pain control and seizures in rats (F1). For this, Wistar rats received oral doses of HP at 36, 72 and 144 mg/kg throughout pregnancy. Tests to evaluate the antinociceptive and anticonvulsant activity of HP were performed in adult F1 rats, which showed a decrease of both responses, suggesting therefore that HP exposition during pregnancy causes changes in neurodevelopment of brain regions related to pain control and seizures in rats.