Comparison of Electrolyte Composition and Crystallization Patterns in Bird and Reptile Tears

Abstract

To compare tear electrolytes and tear crystallization patterns in birds and reptiles, tears were sampled by Schirmer tear test from 10 animals each of Ara ararauna, Amazona aestiva, Tyto alba, Rupornis magnirostris, Chelonoidis carbonaria , and Caiman latirostris , and 5 of Caretta caretta . The aliquots were pooled to assess concentrations of total protein, chloride, phosphorus, iron, sodium, potassium, calcium, and urea. For the tear ferning test, samples of each species were observed under a polarized light microscope at room temperature and humidity. Crystallization patterns were graded according Rolando and Masmali scales. There was more total protein and urea in owl and sea turtle tears, respectively, than in the other animals tested. Electrolyte balance was similar for all species, with higher sodium, chloride, and iron. In birds, Rolando-scale grades of tear crystallization patterns ranged from I to II, and from 0 to 2 using the Masmali scale; in reptiles, grades were II to IV (Rolando) and 2 to 4 (Masmali). Crystallization arrangements of some species had higher scores, as caimans and sea turtles, possibly due to different the tear composition. Marine and lacustrine species presented higher. The ionic balance of lacrimal fluids of birds and reptiles was similar to that in humans, with higher values of sodium and chloride. However, a similar tear composition did not influence the crystal morphology. Crystallization classification suggested that higher grades and types are due to the different microelements present in the tears of wild species.

Reproducibilidad de la escala de Masmali en la valoración de la película lagrimal

“…El reconocimiento de la importancia y fiabilidad del test de cristalización lagrimal junto a la escala de evaluación de Masmali ha venido ganando terreno, no solo en la evaluación en humanos, sino que su uso se ha extendido a especies animales, constituyéndose una herramienta que viene utilizándose en el estudio de la calidad lagrimal de felinos, aves y reptiles. Varios estudios afirman obtener resultados confiables en estas especies [23].…”

The glycoproteomics of hawk and caiman tears

“…Among the tear components, glycoproteins are potentially important biomarkers; in particular, N-linked glycocomponents have been widely studied in pathological conditions [4,12]. Advances in the methodologies describing PTMs have led to the understanding of the different tear stabilization mechanisms, especially when it is exposed to extreme environmental conditions [5,10,12,16]. Descriptions of wild animals' tear components are scarce [10,16,17], and most of the currently available studies on this are have been conducted on humans [18].…”

“…Advances in the methodologies describing PTMs have led to the understanding of the different tear stabilization mechanisms, especially when it is exposed to extreme environmental conditions [5,10,12,16]. Descriptions of wild animals' tear components are scarce [10,16,17], and most of the currently available studies on this are have been conducted on humans [18]. A description of the tear glycoproteins from bird and reptile species can provide information Research reports on the proteomic profile of the human tear film have revealed from 490 to 1500 different proteins, using different MS methodologies [20][21][22], which demonstrates the complexity and heterogeneity of this fluid.…”

“…The tear film structural matrix of some reptiles, birds and mammals is similar to that described for the human tear film [16,24] and, considering this similarity, the same methodology can be used. The UPKB was used to classify the glycopeptides since it has a more diverse genetic bank information, and it is possible to obtain the best protein characterization.…”

“…Vertebrates interact with the environment mainly through their sense of sight [14]. However, little is known about the tear film composition of birds and reptiles, which are exposed to intense air friction during flight and to dense and dirty water, respectively [10,15,16]. Previous studies showed differences between the tear protein profiles in birds, reptiles, and mammals [10,17,18].…”