title: Optimal preservation of the shark retina for ultrastructural analysis: an assessment of chemical, microwave, and high-pressure freezing fixation techniques.
abstract: Recent advances in microwave chemical fixation (MCF) and/or high pressure freezing (HPF) combined with transmission electron microscopy have resulted in superior ultrastructural detail in a variety of tissue types. To date, selachian tissue has been fixed and processed using only standard chemical fixation (CF) methods, and the resulting ultrastructure has been less than ideal. In this study, we compared the ultrastructure of the fragile retinal tissue from the brown banded bamboo shark, Chiloscyllium punctatum, obtained using CF, MCF, and HPF methods. For all fixation protocols, ultrastructural preservation was improved by keeping the tissue in oxygenated Ringer solution until the time of fixation. Both MCF and HPF produced superior retinal ultrastructure compared to conventional CF. Although HPF occasionally resulted in very high quality ultrastructure, microwave fixation was almost comparable, quicker and far more consistent.
authors.affiliation: School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia. blake.chapman@ uq.edu.au
authors.forename: Blake K
authors.initials: BK
authors.lastname: Harahush
authors.forename: Kathryn
authors.initials: K
authors.lastname: Green
authors.forename: Rick
authors.initials: R
authors.lastname: Webb
authors.forename: Nathan S
authors.initials: NS
authors.lastname: Hart
authors.forename: Shaun P
authors.initials: SP
authors.lastname: Collin
mesh_terms: D000818:Animals; D005615:Freezing; D006874:Hydrostatic Pressure; D046529:Microscopy, Electron, Transmission; D008872:Microwaves; D012160:Retina / Q000187:drug effects* / Q000528:radiation effects* / Q000648:ultrastructure; D012754:Sharks; D013048:Specimen Handling / Q000379:methods*; D016707:Tissue Fixation / Q000379:methods*