A Day in the Lab: Hematoxylin & Eosin Staining for Microscopical Analysis of the Brain

🕒 Approximate reading time: 1-2 minutes

Today's scientific endeavour in the laboratory centred on the task of staining brain sections utilising Hematoxylin & Eosin (H&E) in preparation for microscopy. Captured in the timelapse video below, this meticulous process spanned approximately 3.5 hours.

This experiment forms a pivotal aspect of my ongoing research project at the university. Our primary objective is to determine the therapeutic efficacy of a centrally-administered peptide, introduced 35 minutes post-induction of an experimental stroke model. This determination is achieved by analysing the final infarct volume and the growth of the ischaemic lesion through Magnetic Resonance Imaging (MRI). Given that the acquired MRI images, both Diffusion Weighted Imaging (DWI) and T2-weighted images, do not provide a quantifiable measure of cellular death but rather display varying patterns of oedematous activity, it was necessary to perform H&E staining. This supplementary procedure guarantees the validity of the imaging results post-oedema correction.

Timelapse: Conducting the H&E staining experiment.

Elaborate Methodology of Today's Experiment

A grand total of 54 brain sections underwent staining. Commencing with paraffin-processed brain sections, they were submerged in histoclear, followed by sequential immersion in a series of graded alcohols. Subsequently, the application of Haematoxylin stain took place, trailed by a series of rinses and differentiation in acid alcohol. Post-dehydration, the sections were stained with eosin, proceeded by an additional round of dehydration, and finally immersed in histoclear once more. The stained sections were mounted utilising a distyrene, plasticiser, and xylene (DPX) mounting medium. Under a light microscope, basophilic structures stained by haematoxylin present in a blue shade, whereas eosinophilic structures stained by eosin adopt a pink hue. Thus, neuronal nuclei will be observed as blue, and the cytoplasm, alongside the extracellular space, will manifest as pink.