Who Food Additives Series 59 Safety Evaluation Of ... - ipcs inchem

ACIDIFIED SODIUM CHLORITE 33
sperm heads were scored per animal for abnormalities. No treatment-related effects
were observed (Meier et al., 1985).
Male Sprague-Dawley rats (six per group) were given a single dose of 200
mg sodium chlorite/kg bw by gavage and sacrificed after 2 or 14 days or five daily
doses of 100 mg/kg bw on days 1–5 and sacrificed on day 8 or 17. The testis,
epididymis, seminal vesicles and prostate were excised and weighed, and sperm
number, motility and morphology were assessed. Sodium chlorite was found to have
no effect on organ weights or sperm quality (Linder et al., 1992).
(e)
Immune system
A number of immune activity assays were conducted in female B6C3F1
mice. Groups of eight mice received sodium chlorite in their drinking-water at
concentrations of 0, 0.1, 1, 5, 15 or 30 mg/l for 28 days. Based on the average body
weights and water consumption data provided, these concentrations were equal to
doses of approximately 0, 0.02, 0.2, 0.8, 2.5 and 5 mg sodium chlorite/kg bw per
day, or 0, 0.015, 0.15, 0.6, 1.9 and 3.8 mg/kg bw per day expressed as chlorite. At
termination of the treatment, animals were assessed for immunomodulation using
a number of assays, blood parameters and organ weights. There were no treatmentrelated
differences in weight gain or water consumption and no overt signs of
toxicity. Significant increases in absolute weights of liver, spleen and kidney were
seen at all concentrations of sodium chlorite, but relative organ weights did not differ
from control except for the spleen in the 5 mg/l group. Haematological parameters
were generally unaffected by treatment. A significant increase in reticulocytes was
seen in the 15 mg/l group, but not in other groups. The number of CD8 + T cells was
significantly increased in the highest treatment group. The total number of CD4 + T
cells, B cells, natural killer (NK) cells and macrophages and the total number of
spleen cells remained unaffected by treatment. Spleen immunoglobulin M (IgM)
antibody response to T-dependent antigen from sheep erythrocytes was
determined using a modified haemolytic plaque assay, and antibody forming cells
(AFC) were counted and expressed as AFC/10 6 spleen cells or AFC/spleen. Serum
IgM antibody levels were assessed in the same animals by enzyme-linked
immunosorbent assay (ELISA). Sodium chlorite did not significantly affect the
primary AFC response to sheep erythrocytes in the individual treatment groups;
however, an increasing trend in the AFC response was observed over the range of
doses when the data were expressed as specific activity (AFC/10 6 spleen cells and
AFC/spleen). Spleen cell numbers and serum IgM following exposure to sheep
erythrocytes were unaffected by the treatment; therefore, the authors concluded
that the increasing trend in the AFC response was not a significant change. Spleen
cell mixed leukocyte response to stimulator DBA/2 spleen cells was assessed and
expressed as counts per minute (cpm)/1 × 10 5 cells. No change in spleen cell
response was observed following treatment with sodium chlorite. Peritoneal
macrophage activation was assessed by intraperitoneal injection of 1 ml 10%
thioglycollate to recruit macrophages into the peritoneal cavity. Peritoneal cells were
collected following sacrifice and cultured with stimulants and then B16F10 tumour
cells. Tumour cell proliferation was measured using a liquid scintillation counter and
measured as the per cent suppression of tumour cell proliferation. Sodium chlorite