Penetration of formaldehyde based fixatives into heart.

OBJECTIVES

To investigate the penetration depth of formaldehyde-based fixatives into cardiac muscle samples over the course of fixation.

BACKGROUND

Fixation is the essential step in anatomical studies. However, very little is known about penetration of most common fixatives into cardiac tissue.

METHODS

A total of 40 heart samples were investigated. 4 study groups (n=10 in each case) were formed in such manner they differed only in concentration and type of fixative (1) - 2% formaldehyde phosphate-buffered solution (FPBS); (2) - 4% FPBS (formalin); (3) - 10% FPBS; (4) - alcoholic formalin. Samples were measured before fixation and in the following time points: 24 hours, 72 hours, 168 hours.

RESULTS

The penetration depth differed significantly among studied fixatives (p<0.0001). 100% penetration occurred in all samples after 72 hours in alcoholic formalin solution and after 168 hours in 10% FPBS. After alcoholic formalin fixation, the tissue is more brittle and sub-epicardial blisters were observed in some cases.

CONCLUSIONS

Alcoholic formalin solution is the fastest fixative among the studied ones, however it has several adverse effects on tissue structure. It was found that 10% FPBS is the best and a relatively fast fixative for cardiac morphometric studies.