Rodents have been successfully bred that have brains that are partially composed of human brain cells. Such animals are usually referred to as chimeras by scientists, a reference to the Greek mythological monster usually depicted as an amalgam of a serpent, lion, and goat. Though chimeras of this type may someday lead to breakthroughs in Parkinson’s disease or Alzheimer’s disease research, they are often at the center of ethical debates. One study that has garnered a certain amount of attention in this regard is a project currently underway to develop mice with brains completely formed from human cells.

Antibodies directed against myelin CNPase detect developing and adult myelin and often serve as markers of oligodendrocytes and Schwann cells. A mouse anti-myelin CNPase antibody followed by a goat anti-mouse secondary antibody conjugated to Alexa Fluor 488 was utilized to immunofluorescently label the sagittal section of rat brain tissue presented in the digital image above. In addition, glial fibrillary acidic protein was targeted in the tissue section by treating the specimen with a rabbit anti-GFAP antibody visualized with a goat anti-rabbit secondary antibody conjugated to Alexa Fluor 568. Nuclear DNA was counterstained with Hoechst 33342. Images were recorded in grayscale with a 12-bit digital camera coupled to a Nikon Eclipse 80i microscope equipped with bandpass emission fluorescence filter optical blocks. During the processing stage, individual image channels were pseudocolored with RGB values corresponding to each of the fluorophore emission spectral profiles.