Flow cytometry as a tool in the evaluation of blood leukocyte function in Chelonia mydas (Linnaeus, 1758) (Testudines, Cheloniidae) / A citometria de fluxo como ferramenta para avaliar a função celular de leucócitos sangüíneos de Chelonia mydas (Testudines, Cheloniidae)

Chelonia mydas is a sea turtle that feeds and nests on the Brazilian coast and a disease called fibropapillomatosis is a threat to this species. Because of this, it is extremely necessary to determine a methodology that would enable the analysis of blood leukocyte function in these sea turtles. In order to achieve this aim, blood samples were collected from C. mydas with or without fibropapillomas captured on the São Paulo north coast. Blood samples were placed in tubes containing sodium heparin and were transported under refrigeration to the laboratory in sterile RPMI 1640 cell culture medium. Leukocytes were separated by density gradient using Ficoll-PaqueTM Plus, Amershan Biociences®. The following stimuli were applied in the assessment of leukocyte function: Phorbol Miristate-Acetate (PMA) for oxidative burst activity evaluation and Zymosan A (Saccharomyces cerevisiae) Bio Particles®, Alexa Fluor® 594 conjugate for phagocytosis evaluation. Three cell populations were identified: heterophils, monocytes and lymphocytes. Monocytes were the cells responsible for phagocytosis and oxidative burst.

Chelonia mydas é uma tartaruga marinha que freqüenta o litoral brasileiro para alimentação e nidificação e uma doença denominada fibropapilomatose é uma das mais importantes ameaças à sobrevivência dessa espécie. Desta forma, a definição de uma metodologia que permita analisar a função dos leucócitos sangüíneos torna-se extremamente necessária. Foram utilizadas amostras sangüíneas de C. mydas com e sem fibropapilomas capturadas no litoral norte do estado de São Paulo. As amostras sangüíneas foram colocadas em tubos contendo heparina sódica e transportadas em meio de cultura celular RPMI 1640 estéril e sob refrigeração. Os leucócitos foram obtidos por gradiente de densidade usando Ficoll-PaqueTM Plus, Amershan Biociences®. Os estímulos aplicados foram Miristato Acetato de Phorbol (PMA) para avaliação de burst oxidativo e Zymosan A (Saccharomyces cerevisiae) Bio Particles®, Alexa Fluor® 594 conjugate para avaliação de fagocitose. Foram identificadas três populações celulares: heterófilos, monócitos e linfócitos. Os monócitos foram as células responsáveis pela fagocitose e pelo burst oxidativo.

Evaluation of memory and anxiety in rats observed in the elevated plus-maze: effects of age and isolation

Twenty young(5months)and 20 old(20-24 months) male Wistar rats, isolated or group housed, were tested in the elevated plus-maze to elevated memory and anxiety. Memory was quantified by transfer latency (the time it took for the rat move from the open arm to the enclosed arm) and anxiety by percent entries into the openarms. Isolation decreased the transfer latency of old (session 1 - 119,33 ñ 0.44s; session 3 - 49,67 ñ 12.12s) and young (session 1 -111.20 ñ 8.80s; session 3 -55.90 ñ 13.60s) rats, but did not modify percent entries into the open arms (old-isolated - 5.56 ñ 5.56; old-group housed - 10.18 ñ7.05; young isolated - 35.16 ñ 8.98; young - group housed - 33.21 ñ 8.11). Conversely, aging decreased percent entries into the open arms but did not affect the transfer latency of isolated or group-housed animals. The results indicate that the plus-maze test, unlike other methods for memory evaluation, does not discriminate between young and rats. They also suggest that age increases anxiety and that isolation increases memory levels, but that there is no interaction between age and isolation with regard to their effect on memory and anxiety in rats