Silicon carbide

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Comparable to guideline study with limitations which do not impair the overall conclusion from the data. Sufficiently detailed description of the test procedure in accordance with scientific standards (critical supporting information given, such as species tested, substance identity and dosing procedure).

Data source

Reference

Reference Type:

publication

Title:

Silicon Carbide Induced Pneumoconiosis: A Microscopic and Biochemical Experimental study

Author:

M Petran, A Cocârla, DC Olinici

Year:

1999

Bibliographic source:

J Occup Health 1999; 41: 253- 258

Materials and methods

Principles of method if other than guideline:

experimental model by intratracheal instillation, BAL analyses

GLP compliance:

not specified

Test material

Test material information

1

Reference substance name:

Silicon carbide

EC Number:

206-991-8

EC Name:

Silicon carbide

Cas Number:

409-21-2

Molecular formula:

SiC

IUPAC Name:

methyl-λ¹-silanylidyne

Test animals

Species:

guinea pig

Sex:

male

Administration / exposure

Route of administration:

other: suspended in physiological solution

Type of inhalation exposure:

other: intratracheal instillation

Vehicle:

other: physiological solution

Remarks on duration:

single dose

Concentrations:

50 mg standardized SiC suspended in 1 ml physiological solution

No. of animals per sex per dose:

30

Control animals:

yes

Statistics:

statistical method employed: Student's test

Results and discussion

Effect levels

Dose descriptor:

other: non applicable

Remarks on result:

other: SiC particles do not cause lung fibrosis, and in fact, behave in the lung as do other inert dusts such as latex beads or graphite dust.

Body weight:

Whereas the weight of the control animals showed a slight constant increase, in the SiC treated animals a transient decrease was found after instillation, which subsequently returned to normal.

Other findings:

- Lung weight was significantly higher in the SiC treated group.
- Fibrotic lesions following the formation of cell granulomas were observed in the SiC treated group.
- Lung tissue hydroxyproline was increased in the SiC treated group.

Applicant's summary and conclusion

Executive summary:

The pneumoconiogenic effects of silicon carbide were studied in an experimental model by intratracheal instillation of a dose ol 50 mg silicon carbide, standardized and commercialized by Duke Scientific Corporation, in a group of 30 guinea pigs killed at 40, 70 and 100 days, respectively. Lung samples were obtained and they were fixed, included, sectioned, stained with hematoxylineosin, van Gieson and Masson's trichromic and studied under the optical microscope. The microscopic aspects were compared with those of the controls (10 guinea pigs), intratracheally instilled with 1 ml physiological solution (NaCl 0,9%) at the beginning of the experiment and killed with the last group of guinea pigs at 100 days. The optical microscopic study showed important changes in the pulmonary structure: alveolar wall ruptures, infiltration of alveolar septa with round cells and histiocytes, as well as diffuse interstitial fibrosis which was more obvious 100 days after the instillation. Lung tissue hydroxyproline, as a marker of collagen synthesis, showed a significant increase correlated with the ocurrence of fibrosis. The results of the experimental research support the pneumoconiogenic effect of silicon carbide.