A Dissection Method to Harvest Murine Popliteal Draining Lymph Nodes for Ex Vivo Imaging

A lymph node is an ovoid-shaped secondary lymphoid organ present throughout the body that functions in bridging innate and adaptive immune responses by allowing interactions between immune cells.

To isolate a murine popliteal draining lymph node — a node that receives lymph from the hind legs — begin by taking a euthanized mouse fixed on a stage in a prone position.

Prepare the mouse by applying mineral oil to the calf region of the hind legs. The oil prevents fur deposition around the surgical incision site during skin removal.

Make a midline incision from the heel to the knee in the calf region. Dissociate the skin from the underlying musculature and expose the popliteal fossa — a shallow depression behind the knee joint.

The popliteal draining lymph node appears as a translucent sphere inside the fossa — embedded within the adipose tissue of the fossa. Remove the lymph node and place it in a culture dish.

Next, carefully remove the adipose tissue surrounding the node to aid in microscope imaging. Cover the organ with an absorbent sheet soaked in an appropriate buffer. The buffer helps maintain the hydration level to preserve tissue viability.

The popliteal draining lymph node is ready for downstream ex vivo imaging assays.