Isopropyl Alcohol and Methylene Chloride as Alternatives for pre‐plastination Dehydration and Defatting processes

Abstract

Plastination as a technique creates durable, long lasting, realistic specimens with a high value in anatomy teaching and research. While the original protocol using Acetone has shown great results, the use of this substance is restricted in some countries due to socioeconomical or governmental limitations. The aim of this work is to develop a protocol in which acetone has been replaced as a dehydration and defatting medium.Three groups of specimens were procured. Each of them had a sample of abdominal organs with varying fragility (kidney‐liver‐small intestine), skeletal muscle and brain tissue. Group 1 and 2 (G1–G2) were previously fixated with formaldehyde 4%, while group 3 (G3) was preserved in a glycerin‐based formaldehyde free solution. A conventional plastination technique was carried out including fixation, dehydration, defatting, forced impregnation and curing.All groups were fixated with formaldehyde 10%, although G3 required cleansing with a 50% ethylic alcohol (EA) solution to remove the glycerin. G1 was dehydrated and defatted with EA. G2 & G3 were dehydrated with isopropyl alcohol (IA), and defatted with methylene chloride (MC). All groups were impregnated in low temperatures with 1% S3–S10 Biodur silicone‐cross linker mixture. Finally, curing was divided in two steps, passive curing for 6 months and S6 cross linking. The specimens were analyzed based on tissue retraction, color degradation, morphological alterations and final specimen pliability.G1 showed maximum tissue shrinkage, morphological alteration and color degradation acquiring a brownish tone. G2 & G3 suffered less tissue retraction, color degradation was minimal, morphological alteration was not observed. Specimen pliability remained the same across the three groups, specific tissues such as skeletal muscle, blood vessels and intestine were more pliable.Lesser tissue retraction and increased color preservation were obtained with the use of IA and MC for dehydration and defatting, compared with exclusive use of EA for both steps. Specimens previously preserved with glycerin‐based formaldehyde free solutions where successfully plastinated with this technique.While this study serves as a proof of concept that IA and MC are viable substitutes for Acetone in the dehydration and defatting steps, the lack of objective measurements and a control group with acetone are strong limitations of this study. Future studies with a higher number of standardized specimens and controls are needed to determine the impact of the proposed replacement in the plastination protocol.