Lead acetate as a vital marker for the analysis of bone growth

The use of lead acetate as a vital stain adds another method for the study of periodic appositional patterns of hard tissues. The distinct advantage of this technique is that these tissues can be decalcified and examined histologically without loss of the marker. The following method was used in preparation of the sections shown in the text. The rats received an intravenous injection of 4 mg lead acetate/kg body weight. After sacrifice, the tissues were decalcified in 1% HCL through which H₂S was constantly bubbled. The action of the H₂S gas is to convert the lead at sites of calcification to insoluble lead sulfide. Upon completion of decalcification the sections were embedded in 30% gelatin, and frozen sections at 15–20 μ were cut. The sections were then placed in a 0.1% solution of gold chloride for ten minutes. Next, they were placed in a 5% solution of sodium bisulphate for ten minutes. Subsequently they were washed in distilled water for 30 minutes and finally fixed in a 5% solution of sodium thiosulphate. No additional staining was used. The sections were then mounted with glycerine jelly. The resulting lead lines are sharp and therefore conducive to quantitative measurements. Because of the relatively thin sections cut, histologic details can be observed.