Comparison between formaldehyde and salt solutions for preservation of human liver and brain slices

Abstract

Background : Formaldehyde exposure leads to increased risk of cancer. Recent studies reveal that salt solution can preserve human and animal tissues for analysis with high quality equal to formaldehyde.

Objective : To compare the effectiveness of formaldehyde and sodium chloride salt solutions in various concentrations for preservation by quantitative measurement of tissue discoloration, volume and weight of human liver and brain slices.

Methods : Sections of liver and brain were obtained from ten deceased subjects, and preserved in 10%, 20%, 26% sodium chloride salt solution (weight/weight) and 10% formaldehyde (volume/volume). The discoloration,
volume and weight of each sample were quantitatively measured by colorimeter on the 1^st day (before the preservation process), 3^rd, 7^th, 14^th, 28^th, and 56^th day of the embalming.

Results : All the brain samples which were preserved in 10% sodium chloride salt solution, decomposed and only 4 samples in the 20% sodium chloride salt solution sample group survived until the 56th day of preservation.
There was no statistically significant difference on the 56th and the 1st day of preservation between 26% sodium chloride salt solution and formaldehyde. The liver samples which were preserved in 10% and 20% sodium chloride salt solutions tended to decompose. There was a statistically significant difference between 26% sodium chloride salt solution and formaldehyde in A (red-green) and L (lightness) color (P - value < 0.001). This means the liver slices preserved in 26% sodium chloride salt solution showed less discoloration than those in formaldehyde.

Conclusions : It is shown that 26% sodium chloride salt solution is an appropriate alternative choice for human liver and brain slice preservation, since it is a non-carcinogenic substance and shows less discoloration than formaldehyde.