Air Quality Criteria for Lead Volume II of II - (NEPIS)(EPA) - US ...

AX5-130
Table AX5-8.3 (cont’d). Bone Cell Cultures Utilized to Test Effects of Lead
Compound
Dose/Concentration
Duration Exposure
Route Species Effects Blood Level Reference
Pb acetate and 210 Pb
label
0–100 µM
20 hr
In medium
Pb acetate
5 or 25 µM
Up to 5 hr
In medium
Pb nitrate
5 µM
20 min
In medium
Pb 2+
5 or 12.5 µM
Up to 100 min
In medium
Mice
(osteoclastic
bone cell
isolation from
calvaria) and
Rat
Osteosarcoma
Cells
(ROS 17/2.8)
Rat
Osteosarcoma
Cells
(ROS 17/2.8)
Rat
(osteoblastic
bone cell
isolation from
calvaria)
Rat
(osteoblastic
bone cell
isolation from
calvaria)
Concentrations as high as 100 µM did not cause toxicity in either cell culture. There
was a slight decrease in growth of ROS cells at 5 µM Pb concentration and a 50%
decrease in growth at 25 µM Pb at day 9.
210 Pb washout experiments with both cell cultures indicated similar steady-state Pb
kinetics and intracellular Pb metabolism. Both cell cultures exhibited one large,
slowly exchanging pool of Pb, indicative of the mitochondrial pool.
Used 19 F NMR in combination with 1,2-bis(2-amino-5-fluorophenoxy)ethane-
N,N,N’,N’-tetraacetic acid (5F-BAPTA) to distinguish and measure concentrations
of Pb 2+ and Ca 2+ in aqueous solution.
Basal concentration of [Ca 2+ ] i was 128 ± 24 nM. Treatment of cells with 5 and 25
µM Pb 2+ produced sustained 50% and 120% increases in [Ca 2+ ] i, respectively, over a
5 hour exposure period.
At a medium concentration of 25 µM Pb 2+ a measurable entry of Pb 2+ into the cells
([Pb 2+ ] i of 29 ± 8 pM) was noted.
Pb (5 µM) linearly raised the emission ratio of FURA-2 loaded cells 2-fold within 20
min of application, most likely due to increase in [Pb 2+ ] i rather than increase in
[Ca 2+ ] i.
Intracellular calcium increased even in the absence of extracellular calcium.
5 or 12.5 µM Pb 2+ applied simultaneously with re-added calcium reduced immediate
CRAC to 70% or 37% of control value, respectively.
During CRAC a large influx of Pb 2+ occurred, leading to a 2.7-fold faster increase in
the FURA-2 excitation ratio. These effects were exclusive of any inhibitory action
of Pb 2+ on calcium ATPase activity.
Not applicable Long et al. (1990)
Not applicable Schanne et al.
(1989)
Not applicable Schirrmacher et al.
(1998)
Not applicable Wiemann et al.
(1999)