A three-dimensional confocal micrograph of a transparent mouse mammary gland (using CUBIC tissue clearing). Contractile cells are responsible for expelling milk out of the mammary gland during lactation. As seen in this image, they form a basket-like network around each milk-producing unit and contract in response to infant suckling, forcing milk towards the nipple. Thousands to millions of milk-producing units are present in the mammary glands of nursing mammals.
Mouse lactating mammary gland tissue was isolated and stained using a smooth muscle actin antibody to reveal the contractile (myoepithelial) cells surrounding each milk-producing cluster. The tissue has been treated with chemicals to make it almost transparent to minimise light scattering (refraction) as it passes through the tissue. This improves resolution and prevents distortion of the image. The final image is depth-coded, with higher structures shown on the red end of the visible spectrum and deeper structures coloured blue/purple. The total width of the image is 331 µm.
