Comparison of Three Histological Techniques for Fat Emboli Detection in Lung Cetacean’s Tissue

Abstract

Fat embolism is the mechanical blockage of blood vessels by circulating fat particles. It is frequently related to traumas involving soft tissues and fat-containing bones. Different techniques have been used for decades to demonstrate histologically fat emboli, being the extremely toxic post-fixation with osmium tetroxide one of the most used techniques in the last decades. In the present study, the osmium tetroxide technique was compared qualitatively and quantitatively, for the first time, with chromic acid and Oil Red O frozen techniques for histological fat emboli detection in the lungs of eight sperm whales that died due to ship strikes. This was also the first time that chromic acid technique was tested in cetaceans. Results showed that the three techniques were valuable for the histological detection of fat embolism in cetaceans, even when tissues presented advanced autolysis and had been stored in formaldehyde for years. Although quantitative differences could not be established, the Oil Red O frozen technique showed the lowest quality for fat emboli staining. On the contrary, the chromic acid technique was proven to be a good alternative to osmium tetroxide due to its slightly lower toxicity, its equivalent or even superior capacity of fat emboli detection, and its significantly lower economic cost.

Near‐infrared double‐illumination optical‐resolution photoacoustic microscopy

“…However, the limitations of DIOR‐PAM should be noted that, it impedes the application of reflection‐mode imaging in vivo. It is only applicable to thin and weak absorbers, such as histological slides, [ 43 ] living cells rich of lipid, [ 44 ] mouse ears, [ 45 ] mesentery. [ 46 ] In addition, our DIOR‐PAM mainly targets to increase the imaging SNR for the thin and weak absorber.…”

Methodological advancements in organ-specific ectopic lipid quantitative characterization: Effects of high fat diet on muscle and liver intracellular lipids

“…To investigate specific ectopic lipids of our two organs of interest, we developed a zebrafish larvae sectioning method. Paraffin embedding, the current gold standard for zebrafish larvae sectioning, requires ethanol dehydration that causes the loss of lipids from tissues and induces morphological changes [ 22 ]. In comparison, our method allows complete tissue conservation of small larvae and does not require dehydration, preventing subsequent deformation of the tissues and loss of lipids.…”

“…While cryosection preparation has been optimized for portions of adult zebrafish [ 21 ], larvae require full body embedding for cryosection due to their small size and heterogeneous texture. Paraffin and resin embedding techniques described previously are either unsuitable to study lipids due to alcohol dehydration [ 22 ] or expensive and time consuming [ 23 ]. Here, we custom-made a cryosection and imaging procedure to visualize and characterize tissue specific LDs in zebrafish larvae.…”

First Case of Brevetoxicosis Linked to Rough-Toothed Dolphin (Steno bredanensis) Mass-Mortality Event in Eastern Central Atlantic Ocean: A Climate Change Effect?

“…For histopathologic analysis, formalin-fixed tissues were embedded in paraffin-wax, sectioned at 5 µm, and stained with hematoxylin-eosin. To rule out fat embolism, osmium tetroxide (post-fixation) was used on selected lung tissue sections (Arregui et al, 2020).…”