Effectiveness of embalming solutions with partial replacement of formaldehyde and phenol with ethanol and sodium chloride on mice over 18 months

Abstract

Animal preservation for anatomy teaching has been required to replace formaldehyde and phenol which represent
a health hazard to humans. A comparative study of embalming solutions with partial replacement of formaldehyde
and phenol with sodium chloride and ethanol was evaluated in mouse cadavers over an 18-month period. Twelve adult
mouse carcasses were divided into six groups of two mice each. After opening the mouse’s skin, the internal organs
were removed and preserved with the remaining cadavers by freezing (Group I, control group) or in the respective
embalming solution (Groups II to VI) and examined after 3, 6, 12 and 18 months. For the embalming solution, the
formaldehyde concentration was reduced from 18% (Group II) to 0.5% (Groups III and IV), 0.1% (Group V), and 0.05%
(Group VI), whereas the phenol and glycerol concentration was reduced from 2.5% and 5% (Group II) to 0.8% and 2%,
(Groups III-VI), respectively. In replacement, 15% table salt/sea salt and 16% ethanol were included in Groups III and
IV. The carcasses and internal organs were blind evaluated by 10 students. The evaluations were compared and
analyzed between Groups and against Group 1 using ANOVA. Results show that embalmed mice in Groups III and IV
retained a good color and flexibility, without decomposition or fungal growth throughout study. In contrast, mice in
Groups V and VI were unsuitable at 3 months. We concluded that a suitable embalming fluid for small animal
preservation was 0.5% formaldehyde, 0.8% phenol, 2% glycerol, 16% ethanol and 15% sodium chloride.