Barium sulfate

Specific investigations: other studies

Administrative data

Endpoint:

mechanistic studies

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

no data available

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: Restricted relevance of the experimental data due to intratracheal route of administration.

Data source

Reference

Reference Type:

publication

Title:

Pulmonary reaction to barium sulfate in rats

Author:

Huston, J.; Cunningham, G.J.

Year:

1952

Bibliographic source:

A.M.A. Arch. Pathol. 54, 430-438

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Barium sulfate was administered to 18 Sprague-Dawley rats via a tracheal catheter. Roentgenograms were taken of the animal and of the lungs (after removal from the body). Histological examinations were performed.

GLP compliance:

no

Type of method:

in vivo

Endpoint addressed:

respiratory irritation

Test material

Test material information

Constituent 1

Reference substance name:

Barium sulfate

EC Number:

231-784-4

EC Name:

Barium sulfate

Cas Number:

7727-43-7

Molecular formula:

BaO4S

IUPAC Name:

barium sulfate

Details on test material:

- Name of test material (as cited in study report): Barium sulfate (veriopaque)
- Physical state: solid
No further details are given.

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Weight at study initiation: 250 and 300g
No further details are given.

Administration / exposure

Route of administration:

intratracheal

Vehicle:

not specified

Details on exposure:

Rats were first anesthetised and were then tied in the supine position to a rat board by means of rubber bands on all four extremities. A fifth band, fitted over the front teeth, immobilised th ehead. The rat was held in a vertical position. The tongue was pulled of the animal as far out and to one side as possible, while the tip of the trachela catheter was placed.

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

no data

Duration of treatment / exposure:

single administration

Post exposure period:

Rats were killed at varying intervals of 30 mintes, 2, 12, 24, 48 and 72 hours, and 7, 15, 30, 94 and 126 days by lethal intraperitoneal injection of thiopental sodium.

Doses / concentrations

Remarks:

Doses / Concentrations:
no test concentration given
Basis:

No. of animals per sex per dose:

18 animals were used in this experiment.

Control animals:

not specified

Details on study design:

No further details are given.

Examinations

Examinations:

Roentgenograms were taken immediately prior to and after injection. Further roentgenograms were taken of the animals before killing and of the lungs after removal from the lungs. These were of value in detecting the lobs which contained barium suspension.
After killing, autopsies were performed immediately, and the lungs removed in toto. The lungs together with the spleen and portions of liver and kidney were fixed in 10% formalin. Sections were made from barium containing whole lobes and by cutting through the hilus in most cases one ore more lymph nodes were included in the sections.

Positive control:

no data

Results and discussion

Details on results:

While in general the animals survived the procedure well, 2 rats died almost immediately from tracheal or bronchial obstruction. Observations show that at first the suspension is taken up by polymorphonuclear leucocytes, which subsequently degenerate and liberate the suspension, which is then taken up by mononuclear cells. When the barium is liberated from these cells, it becomes inspissated into refractile masses. The amount od tissue reaction is slight, and giant cell reaction of the foreign body type commences after about 90 days. Finally, although barium sulfate if present in quantity cannot be completely removed, it is likely to give rise to little fibrosis ultimately.
On the basis of the observations it is concluded that barium sulfate is a relatively inert substance in the tissues and give rise to only a very mild reaction.

Applicant's summary and conclusion

Conclusions:

An experimental study of the reaction of rat lung to the endotracheal injection of barium sulfate suspension is described. Stages of this reaction which are moderately clear-cut have been found, although the changes are mild and insidious. On the basis of the observations it is concluded that barium sulfate is a relatively inert substance in the tissues and give rise to only a very mild reaction.