Develop of experimental model in Bufo arenarum larvae for the evaluation the photosensitizers toxicity.

PAISIO, C, ; LÓPEZ, V, ; RIVAROLA, V,; BERTUZZI, M.

Villa Gral Belgrano, Córdoba,

Congreso; XIV Reunión Científica de la Soc. de Biología de Córdoba; 2003

SBC

Current studies in photodynamic therapy (PDT) focus on the characterization of new photosensitizers. In our laboratory we are heading to the search of new more effective and less toxic photosensitizers. It is of great importance to investigate the toxic activity of these therapeutic compound potentials to know their reaches and limitations. These properties can be determined using in vivo toxicity test. The objective was to develop an experimental model of embryotoxicity test in Bufo arenarum larvae. A substance of activity photosensitivity, the methylene blue (MB) was used. The values of the LC50 (median lethal concentration) and body growth development for this molecule under conditions of darkness and illuminated were obtained. Larvae of Bufo arenarum in stadium I, obtained from a fecundation in vitro were used, maintained in glass Petri dishes in the proportion of 10 larvae (for dish) per 40 ml Ringer diluted solution. To obtain the LC50 in darkness the larvae were exposed to different concentrations of MB. Using the maximum non-toxic dose in darkness (373 μM) was carried of the illumination. The results show that 706 μM concentration corresponds the LC50 in darkness and 373 μM with illumination of 30 min was able to kill to 98.3% of the larvae. The 20.5 μM concentration with 30 min of illumination corresponded of the LC50. In conclusion, combination of MB and light are the responsible for the larval death. The analysis of the corporal dry weight didn?t show differences among the different treatments. Experimental model adapts for the obtaining of the LC50 and embryotoxicity tests with photosensitizers drugs and they can be used with new photosensitizers studied in PDT.