Alternative to formaldehyde and flammable toxic solvents in histotechnology

In this work we propose the "cryostabilization" in ethylene glycol (EG) as a new technique for histochemistry. In our new procedure we test the substitution with EG (at –20°C) with a subsequent infiltration of the samples in a polar resin (Glycol Methacrylate, GMA), easily obtained because EG is miscible with commercial polar resin for histology (Technovit 7100, Kulzer; Historesin LKB; JB-4 Polysciences). The use of EG, a cryoprotectant agent, is thus associated with a polar resin embedding and the polymerisation is performed at 6-10 °C. The procedure preserve either a good morphology of diffusible and labile components, such as lipids and waxes, as tested on several samples of animal and plant tissues. The semi-thick sections then permit an high optical resolution. All the processing is easy to perform and doesn’t require specialised instruments. When possible, the substitution of chemical fixatives, often toxic and cancerogenic, is interesting, because EG constitutes a lower risk for the worker and the environment. EG is not carcinogenic or flammable and moderately toxic (similar to ethanol), has a low vapour pressure and is not easily absorbed by the skin. Proposed possible reproductive effects on women were recently denied (NTP-CERHR, 2004)