Human B cell Burkit Lymphoma Raji
cells (purchased from Pasteur Institute of Iran)
were cultured in RPMI-1640 medium
containing 10% calf serum. Then the cells were
maintained at 37° C in a 5% CO2 air incubator
and with passage every day. Cell culture was
done under sterille conditions and below
laminar-hood. With removal of Raji cells from
flask stock through the use of trypan blue 0.4%
in a suspension of Raji cells,viability was more
than 97% (viability (%)= live cells/live cells
and dead cells x 100).
The other steps were the removal of 75µl
(15000 cell) from the suspension, transfering it
to 96-well plates. Then 10µl of different Zn
concentrations (10 nM -500µM) were added to
all wells except the controls. Under below
laminar-hood and sterille conditions, the plates
were shaken and mixed well. Then the cells
were maintained at 37° C in a 5% CO2 air
incubator. At the end of incubation times (12-
72h), viability and cell proliferation were
determined using both the trypan blue
exclusion dye and MTT assay2
. Also, cell
morphology was evaluated by Wright-Gimsa
staining.
Cytotoxic assay by MTT reduction
This was carried out using the MTTassay
described by Mosmann et al (11). According to
the test principles, the assay was based on the
clevage of the tetrazolium salt (MTT), in the
presence of an electron coupling reagent,by
active mitochondria.The water-insoluble
formazan salt produced has to be solubilized in
an additional step. Cells grown in a 96-well
plate, were incubated with the MTT solution
for approximately 4 hours. After the incubation
period, a water-insoluble formazan dye was
quantitaed using a spectorphotometer (ELISA
reader).The revealed absorbance was directly
correlated to the cell number.
Procedure
After the end-points of incubation time
(12-72 hours) at 37° C and 5% CO2, the Raji
cells were loaded with 10 freshly prepared and
Millipore filtered MTT (5mg/ml PBS) and
incubated for 4 hours at 25° C. After 4 hours of
incubation to each well, 100 µl of isopropanol
were added, and the O.D (optimal density) of
product was evaluated in an ELISA reader at
540 nm wevelengh after 15 minutes