AMMONIUM SULFATE CAS N°: 7783-20-2

OECD SIDS
AMMONIUM SULFATE
5. TOXICITY ID: 7783-20-2
DATE: 18.04.2006
drinking water. This procedure was found necessary to
prevent lung changes and mortality from pneumonia.
EXPOSURE TO THE TEST SUBSTANCE: Half of the pretreated
animals of both groups were exposed to ammonium sulfate (0.5
mg/m3), the other half to filtered air (controls).
The rats were housed and exposed in Hazleton Systems model
1000 stainless steel chambers in compliance with the
National Institutes of Health guidelines (NIH, 1978). They
were maintained on a 12-hr light/dark cycle. Food (Wayne
Labs Animal Diet) and water were available ad lib. Relative
humidity was maintained at 50-60%. Exposures were for 5
hours/day, 5 days/week, for either 4 or 8 months. Half of
the rats exposed for 8 months were sacrificed immediately;
the remaining half were held for an additional 3-month
recovery period. The rats were weighed at 2-week intervals
throughout exposure and recovery period.
MORPHOLOGY AND MORPHOMETRY: For sacrifice, animals were
deeply anesthetized by ip injection of pentobarbital sodium
and weighed. The lungs were perfused in situ with
cacodylate-buffered 2% glutaraldeyhde at 20 cm H20 pressure.
The lungs were removed and stored in the glutaraldehyde
solution. The nasal passages wee gently flushed with 10%
neutral buffered formalin (NBF), and the heads (with skin,
brain, and mandibles removed) were fixed in NBF. The fixed
lung volume was determined by weight of displaced fluid.
Lung slices were examined by scanning electron microscopy
(SEM) and alveolar chord length measurements as well as
determinations of the number of nonciliatated bronchiolar
epithelial cells were performed according to previously
described methods (Busch et al., 1984). Three sections of
the nose and one section from the right cardiac lung lobe
were examined by light microscopy.
PULMONARY FUNCTION: Anesthetized animals were intubated with
an esophageal catheter and an endotracheal tube and placed in
a flow-type plethysmograph. Measurements on spontaneously
breathing rats utilized a syringe to inflate and evacuate the
lungs. Transpulmonary pressure and total lung capacity were
recorded. Residual volume was determined by inert gas dilution
(0.5% neon in air). Single-breath carbon monoxide diffusion
capacity was determined according to the procedure of Takezawa
et al (1980, J.App.Physiol. 48, 1052-1059) with modifications
(Loscutoff,1985, Environmental Research 36, 170-180.), and the
time for a single breath was calculated. Time constant (the
time required for lung volume to decrease by 63% of the total
exhaled volume) was measured by inflating the lungs to total
lung capacity and allowing them to exhale
passively. Quasistatic compliance and single-breath N2
washout were measured in succinyl choline paralyzed rats by
inflating the lungs to total lung capacity with air or O2
respectively, and deflating to residual volume at a flow
rate of 2.5 mL/sec. Functional residual capacity was
measured in paralyzed rats by inert gas dilution.
IMMUNOLOGIC STUDIES: These studies included cellular
measurements that correlate with immune competence.
Mitogen-induced activation of peripheral blood lymphocytes
and spleen cells, assayed by incorporation of
125I-iododeoxyuridine into newly synthesized DNA was used as
an in vitro measure of cell-mediated immunity. The
distribution of the T-cell population in spleen cell
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