Animal tissue culture

Animal Tissue Culture
Ms. Veena Shriram

Introduction
 Cell culture has become one of the major tools used in
the life sciences today.
Tissue Culture is the general term for the removal
of cells, tissues, or organs from an animal
or plant and their subsequent placement
into an artificial environment
conducive to growth. This
environment usually consists
of a suitable glass or plastic
culture vessel containing a
liquid or semisolid medium
that supplies the nutrients
essential for survival & growth.

Historical events in the development of cell culture:
• 1878: Claude Bernard proposed that physiological systems of an
organism can be maintained in a living system after the death of an
organism.
• 1885: Roux maintained embryonic chick cells in a saline culture.
• 1897: Loeb demonstrated the survival of cells isolated from blood
and connective tissue in serum and plasma.
• 1907: Harrison cultivated frog nerve cells in a lymph clot and
observed the growth of nerve fibers in vitro for several weeks.
He was considered by some as the father of cell culture.
• 1910: Burrows succeeded in long term cultivation of chicken embryo
cell in plasma clots. He made detailed observation of mitosis.

Contd..
• 1911: Lewis and Lewis made the first liquid media consisted of sea
water, serum, embryo extract, salts and peptones.
• 1913: Carrel introduced strict aseptic techniques so that cells could
be cultured for long periods.
• 1916: Rous and Jones introduced proteolytic enzyme trypsin for the
subculture of adherent cells.
• 1940s: The use of the antibiotics penicillin & streptomycin in
culture medium decreased problem of contamination in cell culture.
• 1948: Earle isolated mouse L fibroblasts which formed clones from
single cells..
• 1952: Gey established a continuous cell line from a human cervical
carcinoma known as HeLa (Helen Lane) cells.
Dulbecco developed plaque assay for animal viruses using
confluent monolayers of cultured cells.

Contd..
• 1955: Eagle studied the nutrient requirements of selected cells in
culture & established first widely used chemically defined medium.
• 1965: Harris and Watkins were able to fuse human and mouse cells
by the use of a virus.
• 1975: Kohler and Milstein produced the first hybridoma capable of
secreting a monoclonal antibody.
• 1978: Sato established the basis for the development of serum-free
media from cocktails of hormones and growth factors.
• 1982: Human insulin became the first recombinant protein to be
licensed as a therapeutic agent.
• 1985: Human growth hormone produced from recombinant bacteria
was accepted for therapeutic use.

Major development’s in cell culture
technology
• First development was the use of antibiotics
which inhibits the growth of contaminants.
• Second was the use of trypsin to remove
adherent cells to subculture further from the
culture vessel
• Third was the use of chemically defined
culture medium.

Why is cell culture used for?
Areas where cell culture technology is currently
playing a major role.
• Model systems for
Studying basic cell biology, interactions between disease
causing agents and cells, effects of drugs on cells, process and
triggering of aging & nutritional studies.
• Toxicity testing
Study the effects of new drugs.
• Cancer research
Study the function of various chemicals, virus &
radiation to convert normal cultured cells to cancerous cells.

Contd….
• Virology
Cultivation of virus for vaccine production, also
used to study there infectious cycle.
• Genetic Engineering
Production of commercial proteins, large scale
production of viruses for use in vaccine production e.g.
polio, rabies, chicken pox, hepatitis B & measles
• Gene therapy
Cells having a functional gene can be replaced to
cells which are having non-functional gene

Tissue culture
• In vitro cultivation of organs, tissues & cells at defined
temperature using an incubator & supplemented with a medium
containing cell nutrients & growth factors is collectively known
as tissue culture
• Different types of cell grown in culture includes connective
tissue elements such as fibroblasts, skeletal tissue, cardiac,
epithelial tissue (liver, breast, skin, kidney) and many different
types of tumor cells.

Primary culture
• Cells when surgically or enzymatically removed from an organism
and placed in suitable culture environment will attach and grow
are called as primary culture.
• Primary cells have a finite life span.
• Primary culture contains a very heterogeneous population of cells.
• Sub culturing of primary cells leads to the generation of cell lines.
• Cell lines have limited life span, they passage several times before
they become senescent.
• Lineage of cells originating from the primary culture is called a
cell strain.

Cell lines
• Most cell lines grow for a limited number of generations.
Cell Culture Systems
• Two basic culture systems are used for growing
cells. These are based primarily upon the ability of
the cells to either grow attached to a glass or
treated plastic substrate (Monolayer Culture
Sytems) or floating free in the culture medium
(Suspension Culture Systems).

Types of cells
 On the basis of morphology (shape & appearance) or on
their functional characteristics. They are divided into three.
 Epithelial like-attached to a substrate and appears
flattened and polygonal in shape
 Lymphoblast like- cells do not attach remain in
suspension with a spherical shape
 Fibroblast like- cells attached to an substrate appears
elongated and bipolar

Culture media
 Choice of media depends on the type of cell being cultured.
 Commonly used Medium are GMEM, EMEM, DMEM etc.
 Media is supplemented with
antibiotics viz. penicillin,
streptomycin etc.
 Prepared media is filtered
and incubated at 40
C.

Why sub culturing.?
• Once the available substrate surface is covered by
cells (a confluent culture) growth slows & ceases.
• Cells to be kept in healthy & in growing state have
to be sub-cultured or passaged.
• It’s the passage of cells when they reach to 80-
90% confluency in flask/dishes/plates.
• Enzyme such as trypsin, dipase, collagenase in
combination with EDTA breaks the cellular glue
that attached the cells to the surface.

Culturing of cells
• Cells are cultured as anchorage dependent or independent
• Cell lines derived from normal tissues are considered as
anchorage-dependent grows only on a suitable substrate
e.g. tissue cells
• Suspension cells are anchorage
-independent e.g. blood cells
• Transformed cell lines either grows
as monolayer or as suspension

Adherent cells
• Cells which are anchorage dependent
• Cells are washed with PBS (free of Ca & Mg ) solution.
• Add enough trypsin/EDTA to cover the monolayer
• Incubate the plate at 37o
C for 1-2 mts
• Tap the vessel from the sides to dislodge the cells
• Add complete medium to dissociate and dislodge the cells
• with the help of pipette which are remained to be adherent
• Add complete medium depends on the subculture
requirement either to 75 cm or 175 cm flask

Suspension cells
• Easier to passage as no need to detach them.
• As the suspension cells reach to confluency, asceptically
remove 1/3rd
of medium replaced with the same amount of
pre-warmed medium.

Working with cryopreserved
cells
• Vial from liquid nitrogen is placed into 370
C water bath, agitate
vial continuously until medium is thawed.
• Centrifuge the vial for 10 min. at 1000 rpm at RT, wipe top of vial
with 70% ethanol and discard the supernatant
• Resuspend cell pellet in 1 ml of complete medium with 20% PBS &
transfer to properly labeled culture plate
containing appropriate amount of medium.
• Check the cultures after 24 hrs to
ensure that they are attached to the plate
• Change medium as colour changes, use
20% PBS until the cells are established

Freezing cells for storage
• Remove the growth medium, wash the cells by PBS and remove the
PBS by aspiration
• Dislodge the cells by trypsin-versene
• Dilute the cells with growth medium
• Transfer the cell suspension to a 15 ml conical tube, centrifuge at
200g for 5 mts at RT and remove the growth medium by aspiration
• Resuspend the cells in 1-2ml of freezing medium
• Transfer the cells to cryovials, incubate the cryovials at -80o
C
overnight
• Next day transfer the cryovials to Liquid nitrogen

Cell viability
• Cell viability is determined by staining the cells
with trypan blue.
• As trypan blue dye is permeable to non-viable cells
or dead cells whereas it is impermeable to this dye
• Stain the cells with trypan dye and load to
haemocytometer and calculate % of viable cells
%ofviablecells =
No.ofunstainedcellsx100

Common cell lines
• Human cell lines
• MCF-7 breast cancer
• HL 60 Leukemia
• HEK-293 Human embryonic kidney
• HeLa Henrietta lacks
• Primate cell lines
• Vero African green monkey kidney epithelial cells
• Cos-7 African green monkey kidney cells
• And others such as CHO from hamster.

Contaminant’s of cell culture
Cell culture contaminants of two types
• Chemical - difficult to detect caused by endotoxins,
plasticizers, metal ions or traces of disinfectants that are
invisible.
• Biological-cause visible effects
on culture they are mycoplasma,
yeast, bacteria, fungus or also
from cross- contamination of
cells from other cell lines.

Effects of Biological Contamination’s
• They compete for nutrients with host cells.
• Secreted acidic or alkaline by-products ceases the
growth of the host cells.
• Degraded arginine & purine inhibits the synthesis of
histone and nucleic acid.
• They also produces H2O2 which is directly toxic to
cells.

Detection of contaminants
• In general indicators of contamination are turbid culture media,
change in growth rates, abnormally high pH, poor attachment,
multi-nucleated cells, graining cellular appearance,
vacuolization, inclusion bodies and cell lysis
• Yeast, bacteria & fungi usually shows visible effect on the
culture (changes in medium turbidity or pH)
• Mycoplasma detected by direct DNA staining with intercalating
fluorescent substances e.g. Hoechst 33258
• Mycoplasma also detected by enzyme immunoassay by specific
antisera or monoclonal abs or by PCR amplification of
mycoplasmal RNA
• The best and the oldest way to eliminate contamination is to
discard the infected cell lines directly

Basic equipments used in cell culture
• Laminar cabinet-Vertical are preferable.
• Incubation facilities- Temperature of 25-300
C for insect & 370
C for
mammalian cells, CO2 2-5% & 95% air at 99% relative humidity.
To prevent cell death incubators set to cut out at approx. 38.50
C.
• Refrigerators- Liquid media kept at 40
C, enzymes (e.g. trypsin) &
media components (e.g. glutamine & serum) at -200
C.
• Microscope An inverted microscope with 10x -100x magnification.
• Tissue culture ware- Culture plastic ware treated by polystyrene.

Rules for working with cell culture
Never use contaminated material within a sterile area
Use correct sequence when working with more than one cell lines.
 Finding A “Happy” Environment:
 To cell culturists, a “happy” environment usually means an
environment that, at least, allows cells to increase in number by
undergoing cell division (mitosis).
 When conditions are just right, some cultured cells will express
their “happiness” with their environment by carrying out important
in vivo physiological or biochemical functions, such as muscle
contraction or the secretion of hormones and enzymes.
 To provide this environment, it is important to provide the cells
with the appropriate temperature, a good substrate for attachment,
and the proper culture medium.

Temperature : is usually set at the same point as the body
temperature of the host from which the cells were obtained.
Most mammalian cells require 36° to 37°C.
 This temperature range is usually maintained by use of
carefully calibrated, and frequently checked, incubators.
Substrate : Anchorage-dependent cells also require a
good substrate for attachment and growth.
 Glass and specially treated plastics (to make the normally
hydrophobic plastic surface hydrophilic or wettable) are the
most commonly used substrates.
 However, attachment factors, such as collagen, gelatin,
fibronectin and laminin, can be used as substrate coatings to
improve growth and function of normal cells derived from
brain, blood vessels, kidney, liver, skin, etc.
 Often normal anchorage dependent cells will also function
better if they are grown on a permeable or porous surface.

 Many specialized cells can only be truly “happy” (function
normally) when grown on a porous substrate in serum-free medium
with the appropriate mixture of growth and attachment factors.
The culture medium : is the most important and complex
factor to control in making cells “happy”. Besides meeting the
basic nutritional requirement of the cells, the culture medium
should also have any necessary growth factors, regulate the pH
and osmolality, and provide essential gases (O2 and CO2).
 The ‘food’ portion of the culture medium consists of amino
acids, vitamins, minerals, and carbohydrates. These allow the cells
to build new proteins and other components essential for growth &
function as well as providing energy necessary for metabolism.
 The growth factors & hormones help regulate and control
cells’ growth rate & functional characteristics. Instead of being
added directly to the medium, they are added in an undefined
manner by adding 5 to 20% of various animal sera to the medium.

The medium also controls the pH range of the culture and buffers
the cells from abrupt changes in pH. Usually a CO2- bicarbonate
based buffer or an organic buffer, such as HEPES, is used to
help keep the medium pH in a range from 7.0 to 7.4 depending
on the type of cell being cultured.
When using a CO2-bicarbonate buffer, it is necessary to regulate the
amount of CO2 dissolved in the medium. This is usually done
using an incubator with CO2 controls set to provide an
atmosphere with between 2% and 10% CO2 (for Earle’s salts-based
buffers). However, some media use a CO2-bicarbonate
buffer (for Hanks’ salts-based buffers) that requires no additional
CO2, but it must be used in a sealed vessel (not dishes or plates).
Finally, the osmolality (osmotic pressure) of the culture medium is
important since it helps regulate the flow of substances in
and out of the cell. It is controlled by the addition or subtraction of
salt in the culture medium.

• Medium requirements: (often empirical)
• A. Bulk ions - Na, K, Ca, Mg, Cl, P, Bicarb or CO2
B. Trace elements - iron, zinc, selenium
C. Sugars - glucose is the most common
D. Amino acids - 13 essential
E. Vitamins - B, etc.
F. choline, inositol
G. Serum - contains a large number of growth promoting
activities such as buffering toxic nutrients by binding them,
neutralizes trypsin and other proteases, has undefined effects
on the interaction between cells and substrate, and contains
peptide hormones or hormone-like growth factors that
promote healthy growth.
H. Antibiotics - although not required for cell growth,
antibiotics are often used to control the growth of bacterial
and fungal contaminants. Feeding - 2-3 times/week.

. Media and growth
requirements
1. Physiological parameters
A. Temp. - 370
C
B. pH - 7.2-7.5 & osmolality of
medium must be maintained
C. humidity is required
D. gas phase - bicarbonate conc. and
CO2
tension in equilibrium
E. visible light - can have an
adverse effect on cells; light
induced production of toxic
compounds can occur in some
media; cells should be cultured
in the dark and exposed to
room light as little as possible

Basic aseptic conditions
• Swab all bottle tops & necks with 70% ethanol
• Pipette by passing very quickly through the hottest part of
the flame
• Avoiding placing caps & pipettes down on the bench;
practice holding bottle tops with the little finger
• Work either left to right or vice versa, so that all material
goes to one side, once finished.
• Clean up spills immediately & always leave the work
place neat & tidy

Safety aspect in cell culture
• Possibly keep cultures free of antibiotics in order to be able to
recognize the contamination.
• Never use the same media bottle for different cell lines. If caps
are dropped or bottles touched, replace them with new ones.
• Necks of glass bottles prefer heat at least for 60 secs at a
temperature of 2000
C.
• Switch on the laminar flow cabinet 20 min prior to start working.
• Cell cultures which are frequently used should be subcultered &
stored as duplicate strains

Other key facts…….?
• Use actively growing cells that are in their log phase of
growth, which are 80-90% viable.
• Keep exposure to trypsin at a minimum.
• Handle the cells gently. Do not centrifuge cells at high
speed or roughly re-suspend the cells.
• Feeding & sub culturing the cells at more frequent
intervals then used with serum containing conditions may
be necessary

Ms Veena D. Shriram,
Assistant Professor,
Department of Physiology,
B.J. Government Medical College,
Pune 411001
Ph. 020 26218000 Extn 2308
e mail id: omshri5@gmail.com
तन्मे मनः िशिवसंकल्पमस्तु…
‘May my mind be always blessed with
auspicious thoughts’.

Animal tissue culture

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Animal tissue culture