Expression of advanced glycation end-products and NFκB in chick embryos exposed to dioxins and treated with acetylsalicylic acid and α-tocopherol

Dioxins have adverse and multifaceted effect on body functions. They are known to be carcinogens, immunotoxins, and teratogenic agents. In vivo, transformation of dioxins occurs after their interaction with the aryl hydrocarbon receptor (AhR) and leads to formation of proinflammatory and toxic metabolites. The aim of this study was to verify whether α-tocopherol (vitamin E) and acetylsalicylic acid (ASA), could reduce the damage caused by the action of dioxins. Fertile chicken eggs were injected with a solution of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), followed by the injection of α-tocopherol or acetylsalicylic acid. Organs such as heart and liver were dissected from the chick embryos at d 13 and 19 of development and subjected to immunohistochemical analysis of presence of advanced glycation end products (AGEs) and nuclear factor kappa B (NFκB) in tissues. The AGEs were used as the marker for exposure to dioxins, since it is well established that their level increases in dioxin-damaged tissues. Formation of AGEs was evaluated in embryos exposed to dioxin and treated with vitamin E and/or ASA (against dioxin-exposed, untreated controls). We have found that TCDD causes developmental disorders and increases the level of AGEs in chick embryo tissues. The use of such pharmacological agents as vitamin E, ASA, and combination of ASA and vitamin E, inhibited formation of the AGEs in 13-day-old embryos and reduced the AGEs level in embryos after 19 d of the development.

Tumor histopathology following new sensitizers: dithiaporphyrin- and sulfoxaporphyrin-mediated photodynamic therapy

BACKGROUND

Our main aim was to evaluate tumor histopathology following new sensitizer-mediated photodynamic therapy (PDT).

MATERIALS AND METHODS

In order to complete our studies we decided to use photosensitizers, i.e. dithiaporphyrin (DTP) and sulfoxaporphyrin (OXA) in combination with halogen lamp irradiation of presensitized tumors. The doses of sensitizers were: 2.5, 5.0, 7.5 and 10.0 mg/kg of body weight and total light doses were: 50, 100 and 150 J/sq.cm at the selected wavelength. Following such a treatment we have evaluated tumor necrosis of BFS1 fibrosarcoma growing on BALB/c mice. Together with tumor necrosis evaluation we have examined skin response to photodynamic treatment.

RESULTS

We have found that both new sensitizers caused significant tumor damage at no skin alterations. The induction of tumor necrosis seemed to be dose dependent, i.e. higher photodynamic doses (sensitizer dose x light dose) resulted in more severe damage to the tumors than the lower doses.

CONCLUSION

Our study showed that BFS1 fibrosarcoma is highly sensitive to PDT after application of new sensitizers. Both compounds can be considered as potent tumor photosensitizers in future clinical trials.

New potent sensitizers for photodynamic therapy: 21-oxaporphyrin, 21-thiaporphyrin and 21,23-dithiaporphyrin induce extensive tumor necrosis

New sensitizers for photodynamic therapy (PDT) are reported. These compounds, namely 21-thiaporphyrin, 21,23-dithiaporphyrin and 21-oxaporphyrin, reveal some of the properties required for such therapy. Their physicochemical, chemical and pharmacological features meant that we could use them in the treatment of transplantable BFS1 fibrosarcoma in Balb/c mice. New sensitizers and the well-known chlorin e6 (Ce6) were used in doses of 2.5, 5.0, 7.5 and 10.0 mg/kg body weight, given intraperitoneally and followed by light irradiation, the total light doses being 50, 100 and 150 J/cm(2) within 24 h after injection. The effectiveness of new sensitizers in PDT was evaluated with in terms of tumor necrosis intensity, the survival time of treated animals, the rate of tumor response (complete/partial/no response), and skin photosensitivity. These results were compared to results obtained in analogous conditions after Ce6-PDT. Distribution studies revealed that the highest concentration of new compounds occurred within 24 h after injection. The results of these experiments confirmed that 21-thiaporphyrin, 21,23-dithiaporphyrin and 21-oxaporphyrin can be considered as potent tumor photosensitizers that do not exert any unwanted effects, primarily skin photosensitization. We suggest that these porphyrins are possible sensitizers to be applied in clinical PDT.