120 • Alternatives to Animal Use in Research, Testing, and Education 
Figure 6-2— Schematic of Experimental 
Organ Perfusion 
SOURCE: C. Chubb, The University of Texas Health Science Center at Dallas. 
Organ Perfusion: Mouse Testis With 
Pipette Introduced Into Artery 
CM 
III 
Ptolo credit: C. Chubb, The University of Texas Health Science Center at Dallas 
Whole organs are not generally amenable to long- 
term in vitro culture or growth. The size and com- 
plexity of whole organs make it impossible for them 
to receive sufficient nourishment for normal func- 
tion without external support. Nevertheless, whole 
organs are fundamental to many types of anatomy, 
histology, and pathology because of their suitabil- 
ity for the examination of relationships between 
cells and tissues, and they can be sustained in cul- 
ture for hours or days. 
Cryostat sections (thin slices of frozen tissue cut 
with a microtome) through organs are maintained 
in vitro for oncology studies into organ-specific 
adhesion of metastatic tumor cells. This method 
closely reflects the in vivo event and therefore 
could eventually reduce the use of whole animals 
in a very active research area (159). 
Whole mammalian embryos, in addition to their 
obligatory use in the investigation of basic devel- 
opmental biology, have been cultured in vitro for 
other purposes. Protocols have included exami- 
nations of the effects of hormones and teratogens 
(42). 
Tissue Culture 
Many normal and pathological tissues from hu- 
mans and a variety of animal species can be suc- 
cessfully maintained and studied in culture. Indeed, 
the progress that has been achieved since 1907, 
when R.G. Harrison first maintained frog neural 
tissue outside of the body for weeks, has changed 
the field of tissue culture from an art into a science. 
Keeping cultures of anything other than bacteria 
or viruses alive for more than a few hours was 
problematic until the 1950s, when investigators 
began to gain a better understanding of the re- 
quirements of cells and the addition of antibiotics 
to culture systems. The viability of cultures was 
extended substantially by controlling bacterial con- 
tamination. 
In tissue culture, isolated pieces of a living organ- 
ism are maintained with their various cell types 
arranged as they were in the original organism 
and with their differentiated functions intact. Such 
cultures are both “better” and “worse” than cul- 
tures of a single cell type. They are better in that 
the effects of manipulation can be observed in a 
more natural environment and different cell types 
can interact as they would in vivo. They are worse 
in that they are much more difficult to maintain. 
Although tissue -culture experiments require the 
sacrifice of an animal, they can be viewed as alter- 
natives to animal use since numerous sections of 
adjoining tissue can be removed and compared. 
In this way, two or more treatments are adminis- 
tered to tissues, rather than to a number of indi- 
vidual animals. 
