What type of tissue does methylene blue specifically stain?

Methylene blue is a vital stain commonly used in endoscopic and surgical procedures to enhance visualization of certain tissues. Specifically, it has a strong affinity for the absorptive intestinal epithelium, which consists of enterocytes that line the intestine and are responsible for nutrient absorption. This selective staining is due to the presence of transport proteins and other cellular structures in absorptive cells that take up the dye, allowing clinicians to differentiate these cells from others during examination.

The staining of absorptive intestinal epithelium aids in identifying abnormal areas, such as dysplastic or neoplastic changes, but the stain itself is not specific to neoplastic tissue. This distinction is critical in endoscopic procedures where accurate visualization is necessary for diagnosis and treatment planning. Other tissues listed, such as squamous cells or adipose tissue, do not have the same level of affinity for methylene blue, making this choice the most appropriate regarding the specific tissue type that methylene blue targets.