[Health survey of plant workers for an occupational exposure to ammonium perchlorate].

OBJECTIVE: To understand the occupational hazards of ammonium perchlorate dust on operating workers and to provide the basis preventive measures for protecting the workers' health. METHODS: 36 workers exposed to ammonium perchlorate dust and 48 unexposed workers from one factory were selected as the exposure and control groups. Investigations on the general condition, sampling of dust in the workplaces and a special medical examination were conducted for two groups, including occupational history, clinical manifestations, blood routine test, hepatic and renal functions, indexes of thyroid hormone, spirometric test and chest X-ray. RESULTS: The total dust concentration of AP in the batch plant reached to 51.63 ± 43.27 mg/m(3), exceeding the U.S. Occupational Safety and Health Administration (OSHA) permission exposure limits. The systolic blood pressure in the exposure group was higher than that of the control group (146.14 ± 21.03 VS 134.67 ± 18.58), and the difference was statistically significant (P < 0.05). The detection rates of the cumulative total symptoms, short of breath and skin itch symptoms in the exposure group were significantly higher than those in the control group (86.11% VS 66.67%; 30.56% VS 12.50%) (P < 0.05), respectively. FT(3) level in the exposure group significantly lowered than the control group, and the difference was statistically significant (P < 0.01); The pulmonary function result showed that FEV1/FVC% in the exposure group was lower than that in the control group (106.50 ± 28.99 VS 111.70 ± 19.72), but the difference was not significant. X-ray examination revealed one case of pulmonary X-ray abnormalities in the exposure group, diagnosis of pneumoconiosis, and one case with about 1.0 × 1.0 small nodules detected on the left of lung door area in the control group. CONCLUSIONS: The systolic blood pressure of workers in the exposure group was significantly higher, which could not exclude related to the exposure to AP dust; The T(3) levels in the exposure workers were lower than those in the control group, which may due to AP exposure, suggesting that long-term chronic exposure to AP dust may affect thyroid function.

[The effects of ammonium perchlorate on thyroid function and mRNA expression of thyroglobulin and thyroperoxidase].

OBJECTIVE: To investigate the effects of ammonium perchlorate (AP) on thyroid functions and mRNA expression levels of thyroglobulin (Tg) and thyroperoxidase (TPO) genes of rats. METHODS: Thirty SD male rats were randomly divided into six groups: control group, iodine-deficient group, low dose AP group (130 mg/kg), moderate dose AP group (260 mg/kg), high dose AP group (520 mg/kg) and high iodine-combined group. After the rats were exposed orally for 90 days, serum free-thyroxine (FT(4)), free-triiodothyronine (FT(3)) and thyroid stimulating hormone (TSH) were measured using radioimmunoassays. mRNA expression levels of thyroglobulin (Tg) and thyroperoxidase (TPO) genes were detected by real-time quantitative PCR. RESULTS: Serum FT(4) levels in moderate dose AP group and high dose AP group were [(9.540 ± 1.327) fmol/ml] and [(6.509 ± 1.949) fmol/ml] respectively, which were significantly lower than that [(13.505 ± 1.276) fmol /ml] in control group (P < 0.05 or P < 0.01). Serum TSH level in high dose AP group was [(1.227 ± 0.295) mIU/L], which was significantly higher than that [(0.545 ± 0.282) mIU/L] in control group (P < 0.05). The mRNA expression levels of thyroglobulin (Tg) gene in all groups exposed to AP were significantly lower than that in control group (P < 0.01). The mRNA expression level of thyroperoxidase (TPO) gene in high dose AP group was significantly higher than that in control group (P < 0.05). CONCLUSION: AP can reduce the serum FT(3) and FT(4) levels of rats, increase the serum TSH level of rats and decrease obviously the mRNA expression levels of Tg and TPO genes. In addition, high iodine can reduce the toxic effects of AP on thyroid gland of rats to some extent.

Biomarker expression in lung of rabbit with pulmonary fibrosis induced by ammonium perchlorate.

Ammonium perchlorate (AP), an oxidizer, has been used in solid propellants. Although AP exposure has been suspected as a risk factor for the development of pulmonary fibrosis, data are still inconclusive. To evaluate the pulmonary toxicity and the potential pulmonary fibrosis caused by occupational exposure to this compound, 25 male rabbits were randomly allocated into five groups to receive AP or bleomycin or saline by intratracheal injection. All rabbits were sacrificed and total RNA from the lungs was extracted. Expressions of types I and III collagens, transforming growth factor-ß(1) (TGF-ß(1)) and tumour necrosis factor-α (TNF-α) messenger RNA (mRNA) were measured by reverse transcription-polymerase chain reaction (RT-PCR). The expressions of type I and III collagen mRNA in low, moderate and high dose AP groups were significantly higher (p < 0.01 or p < 0.05) than that in the saline group. There was also a significant increased level of TGF-ß(1) and TNF-α mRNA in the three AP groups compared with saline control group (p < 0.01 or p < 0.05). These results reveal that AP can increase gene expressions of types I, III collagens, TGF-ß(1) and TNF-α in lung of rabbits exposed to AP. The overexpression of these biomarkers were considered as effective indicator linking to the development of pulmonary fibrosis and finally demonstrated that AP has potential to induce pulmonary fibrosis.

[The effects of ammonium perchlorate on thyroid function and testis in male rats].

OBJECTIVE: To study the effects of ammonium perchlorate (AP) on the levels of thyroid hormone and the testis function of male rats. METHODS: Twenty male rats were randomly divided into 4 groups: control group, low, middle and high AP group. The rats were exposed orally to 0, 130, 260 and 520 mg AP/kg a day for 80 days. The levels of thyroid hormone, testosterone in serum and sperm motility were measured and the testis histological change was observed as well. RESULTS: The increase of body weight in high AP group was significantly lower than that in the control group (P < 0.01). The organ coefficients of testis and thyroid in high AP group obviously enhanced, as compared with the control group (P < 0.01). The free thyroxin (FT4) levels of serum in all AP treated groups were significantly lower than that of the control group (P < 0.05). There were no differences of serum FT3 levels between all AP groups and control group, while serum TSH levels in middle and high AP groups decreased significantly, as compared with control group (P < 0.01). In terms of sperm motility, the percentage of Grade A and B sperm in middle and high groups were 12.3% +/- 2.52% and 14.8% +/- 5.93%, 17.7% +/- 4.63%, 15.8% +/- 2.28% respectively, which were significantly lower than that (27.8% +/- 8.70%) in control group (P < 0.01). The percentage of Grade D sperm in middle and high groups were 38.0% +/- 3.61% and 40.0% +/- 8.99%, respectively, which were significantly higher than that (17.0% +/- 5.00%) in control group (P < 0.01). No difference of serum testosterone level between all AP groups and control group was observed. CONCLUSION: AP can influence the levels of thyroid hormone and reduce the serum FT4 levels in rats. The main toxic effects on male reproductive system may decrease the sperm motility.