Histological description of Cerdocyon thous (Linnaeus, 1766) respiratory system / Descrição histológica do sistema respiratório de Cerdocyon thous (Linnaeus, 1766)

The massive agricultural expansion converted the Cerdocyon thous, a South American native predator, in vulnerable specie. Basic data, such as histological description, are important to raise awareness on animal species, helping on preservation strategies. Considering the difficult in obtain samples, as the euthanasia of wild animals for this purpose is not allowed, data on histology are very scarce or inexistent. The objective of this paper was to provide a detailed histological description of the trachea and bronchial tree of the crab-eating fox Cerdocyon thous (Linnaeus, 1766). The specimens (one adult male and one adult female) used were provided by the Federal University of Pelotas (Pelotas, RS, Brazil) Rehabilitation Center of Wild Fauna (NURFS). Tissue samples were fixed in 10% formalin and included in paraffin. After slicing, samples were stained with HE (hematoxylin and eosin), PAS (periodic acid-Schiff) and resorcin fuchsin. Trachea had an average diameter of 7.87mm, and approximately 57% of the mucosa ciliated pseudo-stratified columnar epithelium was composed of goblet cells, mostly in the dorsal region. Bronchia and bronchioles had a mucosal fold with higher number of goblet cells. Using all these techniques there is no great remarkable differences from C. thous trachea and lung, when compared with the previous described structures for carnivores and most mammals, except for the goblet cells "regionalization". Described results are important to understand the animal physiological and behavioral habits, allowing the development of preservation and protection strategies.(AU)

A expansão agrícola maciça tornou o Cerdocyon thous, um predador nativo sul-americano, vulnerável. Dados básicos, tais como descrição histológica, são importantes para aumentar o conhecimento sobre as espécies, ajudando nas estratégias de preservação. A eutanásia de animais selvagens para a coleta de amostras não é permitida, por isso os dados sobre a histologia são muito escassos ou inexistentes. O objetivo deste trabalho foi de fornecer uma descrição histológica detalhada da traqueia e árvore brônquica do cachorro do mato Cerdocyon thous (Linnaeus 1766). Os espécimes (um macho e uma fêmea adultos) utilizados foram fornecidos pela Universidade Federal de Pelotas (Pelotas, RS, Brasil), Centro de Reabilitação da Fauna (NURFS). As amostras de tecido foram fixadas em formalina a 10% e incluídas em parafina. Após o corte, as amostras foram coradas com HE (hematoxilina e eosina), PAS (ácido periódico de Schiff) e resorcina fucsina. A traqueia tinha um diâmetro médio de 7,87 milímetros e aproximadamente 57% do diâmetro do epitélio colunar pseudo-estratificado ciliado da mucosa composto por células caliciformes, principalmente na região dorsal do órgão. Os brônquios e bronquíolos apresentaram cararísticas similares aos outros animais, contudo aparenta ter maior número de células caliciformes. Usando distintas técnicas de coloração, observou-se que não há diferenças notáveis da traqueia e do pulmão de C. thous quando comparados com os dados para carnívoros e para a maioria dos mamíferos, exceto a regionalização de células caliciformes. Os resultados descritos são importantes para compreender a fisiologia dos animais e hábitos comportamentais, permitindo o desenvolvimento de estratégias de preservação e proteção.(AU)

study of histological effects of solder fumes in rat lungs

To determine the potential toxic effects of manual soldering flux cored solder wire on lung of the rat as an experimental model. A total number of 48 adult male rats were divided into experimental [n=30] and control [n=18] groups. Based on exposure time to solder fume, each group was further subdivided into 2, 4 and 6 week subgroups. Rats of experimental groups were exposed to fume in exposure chamber for 1 hour/day [Research Center of Zahedan University of Medical Sciences, 12 Apr 2005 to 14 May 2005]. The amount of fumes were measured daily by standard methods. At the end of experiment, lung specimens were collected from each experimental and control subgroups. Tissue samples were processed routinely and thickness of epithelium in bronchioles and interalveolar septas were measured in stained microscopic slides. Obtained data were analyzed by SPSS. Statistical analysis of data for thickness of epithelium in bronchioles showed that there was only a significant difference between 4 week experimental and control subgroups [P< 0.001]. Analysis of data for thickness of interalveolar septa showed statistically significant differences between experimental and control subgroups of 4 and 6 weeks [P< 0.001]. Histological examination was also revealed an inflammatory process in bronchioles and disorganized architecture in alveoli of lung in experimental subgroups. The result showed that solder fume can change the normal architectures of epithelium in bronchioles and alveoli of the lung and it seems that the severities of changes were dependent on the exposure time