Fluorescent in situ hybridization in liver cell touch preparations from autopsy

The objective of the present study was to develop a simplified and low-cost protocol for the investigation of congenital anomalies of chromosomal etiology by fluorescent in situ hybridization (FISH) using probes for chromosomes X, 18, 13/21 in liver cell touch preparations obtained from autopsies performed at the University Hospital of the Faculty of Medicine of Ribeirão Preto. Liver touch preparations were obtained from 11 autopsy cases and fixed in 95% ethanol or methanol:acetic acid (3:1). The FISH technique was carried out according to the protocol of Pinkel with modifications, using probes for chromosomes X, 18, 13/21. There was no significant difference in labeling intensity, quantity of nuclei, or number of signals present per nucleus between the materials fixed with the two fixatives. Similar results were obtained with different times of storage up to 14 months at -20 degrees C. We concluded that the use of touch preparations pretreated with acetic acid and fixed in 95% ethanol represents an efficient, practical, and low-cost method of cell preparation for FISH analysis.