university of california, san diego histology shared resources

Liver: Take a large lobe of the liver with gall bladder and slice it flat and fix whole
Ovaries, Uterus, Vagina, Bladder: The uterus can be identified from the two horns which extend up from
the cervix into the pelvis and ends with the ovaries that are just below each kidney. Cut across the cervix
and lift out the uterus with forceps.
Testes: Testes should be located and taken out whole as gently as possible so as to prevent them from
rupturing. The epididymis may be taken along with them especially if the study requires their analysis.
Prostate: The prostate is just underneath the bladder in the males. It can be taken whole with the bladder
to be fixed together for easy identification at the time of trimming for tissue processing.
Intestinal Tract (Stomach, Ileum, Cecum, Colon, Rectum): Grasp the abdominal end of the esophagus
and begin to disembowel the GI tract until the rectum is reached. Care should be taken not to stretch out
the mesenteric fat so that harvesting of the mesenteric lymph nodes can be possible after fixation.
The small intestine should be sectioned into 4-5 parts before immersion fixation.
The COLON is dissected away from the rest of the bowel and opened along the anti-mesenteric aspect.
Taking a swab stick, roll up the FRESHLY opened colon onto the stick so that a compact roll is the end
result.
DO NOT TRY TO ROLL after rinsing the gut in PBS, it will not stick together to make a good roll.
Always use the same method to roll, anal end first always OR small intestine end first, on the inside of the
roll.
Fix the rolled up colon on the stick, in a 15 ml tube with fixative and submit for histologic embedding
and sectioning.
rolled up colon
on a stick
to be immersed
in fixative
Mammary tissue: The inguinal and axillary mammary glands are visible as yellow fat pads adherent to the
underside of the skin beneath a fascial plane. They should be dissected away from the overlying skin.
Skeletal muscle: A small piece of the abdominal wall may be sectioned. If fixing entire carcass, it can be
left intact and a piece can be cut during trimming.
Bone: Turn the mouse over onto its ventral surface. Using forceps and scissors (scalpel is also acceptable)
lift the skin off the left hind and snip off. This will make the bicep femoris and adductor muscles more
readily visible. Cut the limb off right at the juncture of the hip socket and ankle. Repeat this procedure
with the right limb.
Skin: A snip of one of the ears at least half way down to the juncture of the scalp will be sufficient.
Brain: FOR OPTIMAL MORPHOLOGY< it is best to perfuse the animal with freshly prepared 4%
paraformaldehyde before removing the brain for further fixation, before processing into paraffin blocks.
Grasp scalp on the crown of the head with forceps and snip off skin to see skull clearly (see page 9 and 10
of Atlas). While grasping the orbital of each eye with forceps, move scissors slightly underneath the skull
, and run tip of scissors between skull and brain, keeping scissors horizontal, along the plane of the cutting