Investigation of factors influencing erythrocyte osmotic fragility among selected ectothermic and endothermic vertegrates.

Abstract

Erythrocyte Osmotic Fragility (EOF) is a quantitative measurement of erythrocyte strength and its ability to withstand varying osmotic gradients. An increased EOF is associated with decreased cell strength. I hypothesized that aquatic/semi-aquatic ectothermic vertebrates because they are likely to be exposed to varying osmotic gradients would have stronger erythrocytes than terrestrial ectothermic vertebrates that have relatively constant osmotic surroundings. The EOF for amphibians investigated supported the hypothesis, however, the EOF results for the reptiles investigated did not. Additionally, the EOF of some endotherms was investigated to compare EOF of ectotherms and endotherms. Both amphibians and reptiles showed lower EOF values than did endothermic vertebrates. The effect of temperature on EOF was also investigated at temperatures of 5,25, and 38°C. At the higher temperatures EOF decreased which showed more osmotically resistant erythrocytes as temperature increased. This effect was found in all the ectothems and endotherms investigated. Along with EOF data presented for some mammals, birds, reptiles, and amphibians, general blood measurements were taken including packed cell volume, red blood cell counts, hemoglobin concentrations, and nucleus to cell perimeter ratios when a nucleus was present. These blood measurements were taken to provide baseline information of the hematology of these organisms as well as to see if any of these blood properties had an effect on EOF. A significant effect was shown with mean cell volume (MeV) explaining 50% of the variation that was seen in EOF.