Preparation and observation of fresh-frozen sections of the green fluorescent protein transgenic mouse head

Abstract

Hard tissue decalcification can cause variation in the constituent protein characteristics. This paper describes a method of preparating of frozen mouse head sections so as to clearly observe the nature of the constituent proteins. Frozen sections of various green fluorescent protein (GFP) transgenic mouse heads were prepared using the film method developed by Kawamoto and Shimizu. This method made specimen dissection without decalcification possible, wherein GFP was clearly observed in an undamaged state. Conversely, using the same method with decalcification made GFP observation in the transgenic mouse head difficult. This new method is suitable for observing GFP marked cells, enabling us to follow the transplanted GFP marked cells within frozen head sections.

Fig. 1

GFP mouse head sections prepared using the film method. 20-µm-thick sections of 14-week-old GFP mouse, ×20. (A) Fluorescence in a GFP mouse head section prepared by the film method. (B) Light microscopy of a hematoxylin-eosin stained GFP mouse head section prepared using the film method.

Fig. 2

Effect of decalcification on GFP fluorescence. 20-µm-thick sections of a 14-week-old GFP mouse, ×80. (A) Light microscopy of a non-stained GFP mouse nose tip section prepared with the film method without decalcification. (B) Fluorescence of the same section used in (A). (C) Light microscopy of a non-stained chin of GFP mouse head section prepared by the film method with decalcification. (D) Fluorescence of the same section used in (C).