Analysis of the corneal endothelium in eyes of chickens using contact specular microscopy

Abstract

The corneal endothelium is a single layer of polygonal cells essential for corneal transparency. The objective of this study was to assess the parameters corneal endothelial cells in healthy chickens of different ages using a contact specular microscopy. A total 36 eyes of 18 chickens were evaluated in this study. After the humane slaughter of birds and subconjunctival enucleation, the eye bulbs were arranged into three groups according to the age of the chickens. Group 1 consisted of bulbs eyes of 6 chickens with ages ranging from 1 to 3 months old. Group 2 consisted of ocular bulbs 6 chickens with ages ranging from 5 to 12 months old. Group 3 consisted of bulbs eyes of 6 chickens with ages ranging from 24 to 40 months old. The contact specular microscopy was easy to perform and provided data such as endothelial cell density, average cell area and cellular pleomorphism. The results obtained with a contact specular microscopy revealed that the aging causes a decrease in the density of the corneal endothelium healthy chickens. Similarly, increasing the average endothelial cell area as well as the pleomorphism occurs. The present work suggests that the parameters of corneal endothelium of healthy chickens present change with advancing age. Key words: Chickens, cornea, endothelium, contact specular microscopy ResumoObjetivou-se avaliar os parâmetros do endotélio da córnea de galinhas saudáveis de diferentes faixas etárias utilizando a microscopia especular de contato. Foram avaliados 36 bulbos oculares de 18 galinhas. Após o abate humanitário das aves e a enucleação subconjuntival, os bulbos oculares foram dispostos em três grupos distintos de acordo com a faixa etária. O grupo 1 foi composto por bulbos dos olhos de 6 galinhas com idades variando entre 1 a 3 meses de idade. O grupo 2 foi formado por bulbos oculares de 6 galinhas com idades variando entre 5 a 12 meses de idade. Já o grupo 3 consistiu em bulbos oculares de 6 galinhas com idades variando entre 24 a 40 meses de idade. A microscopia especular de contato foi de fácil realização e forneceu dados como a densidade de células endoteliais, área celular média e o pleomorfismo celular. Os resultados obtidos com esse exame revelaram que o avanço da idade acarreta na diminuição da densidade do endotélio da córnea de galinhas. Além disso, ocorre o aumento da área celular endotelial média bem como do pleomorfismo. O presente trabalho sugere que os parâmetros do endotélio da córnea de galinhas apresentam mudanças com o avanço da idade. Palavras-chave: Galinhas, córnea, endotélio, microscopia especular de contato

Corneal endothelial cell density and morphology in rabbits’ eyes using contact specular microscopy

“…However, due to the cellular retraction caused by the preparation for scanning electron microscopy and the increase in the number of cells per square millimeter, they cannot be compared with the values obtained with a specular microscope. It is very well established in many species that a decrease in endothelial density occurs with aging (MORITA et al, 1994;FRANZEN et al, 2010;ALBUQUERQUE et al, 2015;BERCHT et al, 2015;COYO et al, 2016). Results of this study regarding the mean cell density in different age groups were similar to the results obtained for other species of animals with a mean decrease in endothelial cell density with increasing age.…”

“…However, in the present study we made the choice to use the eyes of animals. This methodology using the eyes of animals that have been sacrificed has been used successfully in previous studies (PIGATTO et al, 2006;PIGATTO et al, 2008;FRANZEN et al, 2010;ALBUQUERQUE et al, 2015;COYO et al, 2016). It is well established that the endothelial structure is preserved for up to 6 hours after death (FRANZEN et al, 2010;ALBUQUERQUE et al, 2015).…”

“…Most cells were hexagonal (75%) in shape, with pentagonal (14%) and heptagonal (11%) cells constituting the greater portion of the remaining corneal endothelium. Some studies evaluating animals of a unique age group have already been conducted and concluded that most cells have six sides (PIGATTO et al, 2004;PIGATTO et al, 2005a;PIGATTO et al, 2006;PIGATTO et al, 2008;IGATTO et al, 2009;TAMAYO-ARANGO et al, 2009;FRANZEN et al, 2010;ALBUQUERQUE et al, 2015;COYO et al, 2016). In humans with a healthy cornea, more than 60% of the corneal endothelium cells are six-sided (McCAREY et al, 2008).…”

“…Due to the fact that there is no cellular retraction and it can be used in animals and living humans, specular microscopy is considered the gold standard technique for assessing the corneal endothelium in people and animals (MORITA, 1995;ABIB & BARRETO, 2001;PIGATTO et al, 2006;PIGATTO et al, 2008;FRANZEN et al, 2010;BERCHT et al, 2015;ALBUQUERQUE et al, 2015;COYO et al, 2016). Specular microscopy has also been employed in the evaluation of dogs undergoing cataract removal surgery (NAGATSUYU et al, 2014).…”

“…Specular microscopy, optical microscopy, and scanning electron microscopy (SEM) are among the most widely used methods for corneal endothelium analysis (MORITA et al, 1994;PIGATTO et al, 2009;ALBUQUERQUE et al, 2015;COYO et al, 2016;FAGANELLO et al, 2016). There is consensus that the preparation of corneas for studies using SEM causes cell retraction by reducing the original cell area and increasing the endothelial cell density (VIRTANEN et al, 1984;FAGANELLO et al, 2016).…”