Colocalization of optical coherence tomography angiography with histology in the mouse retina
MICROVASCULAR RESEARCH
Authors: Duggan, Elyse; Smith, Corey A.; Hooper, Michele L.; Chauhan, Balwantray C.
Abstract
Optical coherence tomography angiography (OCT-A) allows in vivo, non-invasive, functional imaging of retinal perfusion. The purpose of this study was to determine the reliability of OCT-A in visualizing the complete retinal vasculature by comparing in vivo OCT-A images to matched ex vivo retinal tissue in mice. Adult female C57BL/6 mice were imaged to obtain OCT-A images of the superficial vascular complex, intermediate capillary plexus and deep capillary plexus. Z-stack fluorescence images of whole-mounted retinas, labeled for vascular endothelial cells by anti-isolectin immunohistochemistry and FITC-dextran perfusion, were generated. The OCT-A and fluorescence images were manually colocalized and vessel length measured for each of the techniques. Mean vessel length among all plexuses showed less than 13% difference between OCT-A and lectin immunohistochemistry and less than 4% difference between OCT-A and FITC-dextran perfusion. The strength of the correlation between OCT-A and lectin immunohistochemistry ranged from 0.46-0.95, while that between OCT-A and FITC-perfusion ranged from 0.67-0.88. OCT-A visualized retinal vasculature in vivo to a similar extent in matched ex vivo histology images. Our results show that OCT-A is a reliable method for acquiring in vivo images of retinal perfusion in mice, with the ability to differentiate each vascular plexus.
Colloid centrifugation reduces bacterial load in chilled dog semen
ANIMAL REPRODUCTION SCIENCE
Authors: Luno, Victoria; Gonzalez, Noelia; Martinez, Felisa; Revert, Ana; Morrell, Jane M.; Gil, Lydia
Abstract
Conventional semen extenders contain antibiotics to prevent bacterial growth. Finding alternatives would be beneficial to minimize the development of bacterial resistance mechanisms. The aim of this study was to determine the effect of Single Layer Centrifugation (SLC) with Canicoll of dog semen on microbial load and sperm quality during cooled storage. Twenty-four ejaculates were obtained from healthy dogs by digital manipulation. Samples were diluted in Tris-citratefructose extender without antibiotics and divided into two treatment groups: SLC-selected samples and unselected samples. Sperm motility (CASA), viability and acrosome integrity (PI/FITC-PNA) as well as bacterial load of each microorganism species (colony-forming units/mL) were assessed at 0 and 48 h of storage at 4 degrees C. Results indicate SLC-selected dog spermatozoa have greater percentages of motility, viability and acrosome integrity (P < 0.05). Bacterial growth in SLC sperm samples was less (P < 0.05) than unselected samples. Removal of individual bacterial species varied from 91 % to 98 % for Escherichia coll. (91.62 %), Streptococcus spp. (98.18 %), Staphylococcus spp.(95.33 %) and Pseudomonas spp. (92.50 %). In conclusion, the use of SLC with Canicoll has the potential to decrease bacterial load in chilled dog semen.