Histochemical detection of the in vivo produced cellular aldehydes by means of direct Schiff's reaction in CCl4 intoxicated rat liver.

A histochemical technique for detection of the in vivo induced cellular aldehydes based on the direct Schiff's reaction is reported in this paper. CCl4-intoxicated rat liver was used as an experimental model. Fresh and non-pretreated rat liver cryostat sections fixed in 10% formol calcium solution and washed in distilled water were exposed to Schiff's reagent. The sections were then immersed in two baths of sodium bisulphite solution, then in water, dehydrated in ethanol, cleared in xylene and mounted in a synthetic anhydrous mounting medium. As Schiff positive areas presented well circumscribed foci which increased with time following intoxication, semi-quantitative planimetric measurements were feasible. The direct Schiff's reaction detects cellular aldehydes in a sensitive, rapid, histologically and topographically estimable way. The appearance of these aldehydes precedes distinctly morphological alterations detectable by other histochemical or histological techniques. No positive results were obtained in control, non-intoxicated rat livers. Inhibition of this direct Schiff's reaction was obtained in positive control rat liver sections preincubated in solutions of aldehyde blockers. Histochemical detection of aldehydes may give useful information on different aspects of tissue and organ intoxication such as their topography, appearance, evolution, extension, consequences and effects of treatment. The direct Schiff's reaction can be considered as a valuable tool in fundamental and applied research dealing with various toxicological, environmental, pathological, cancer-related and therapeutic problems.