Saggital coupe of a mouse Mallory 1900 stain - The world under the microscope

Self-cultured five-day-old mice were anaesthetized with ether. The extremities and tail section were removed and small incisions were made in the skin to allow the fixative to penetrate easily and as quickly as possible. Homemade Bouinse fluid was used as the fixative.

Mice spent several months in the fixative and this is not harmful to the tissue[1]. A major advantage is that the acid component of the fixative has a beneficial effect on decalcifying the accruing bone tissue. After fixation, the mice were rinsed in ethanol 70%, i.e., not first placed in water as is normally done after fixation. This was done to prevent tissue swelling. After the tissue was dehydrated to 100% ethanol or isopropanol, infiltration in Paraplast plus was started. This Paraffin type ensures rapid and complete infiltration.

Blocks were cut on an A&O-820 rotary microtome with Leica 818 high profile blades. Cut thickness was 4µm. After staining, Depex resin was used to cover sections.

A Trichrome stain according to Frank Burr Mallory[3] from 1900 was used for this section. For a good result it is recommended to stain several sections and play a bit with the staining times. This is because, for example, the Fuchsin over-stain quickly. It is also advisable to lightly over-stain the Aniline-Orange G step and then go to the desired color intensity with differentiation. The author is more comfortable dehydrating further with isopropanol than ethanol because isopropanol stops differentiation better than ethanol.