[Chronic toxicity of 97% isopropyl thioxanthone in rat by oral administration for 2 years].
OBJECTIVE
To study the oral chronic toxicity of 97% isopropyl thioxanthone (97% ITX) in rats, determine the no-observed adverse effect levels (NOAEL).


METHODS
Four groups of rats were fed with foodstuff containing 97% ITX in the dosage of 1000.0, 250.0, 62.5 mg/kg respectively for 2 years. The general behavior, body weight, food availability ect. were observed during the experiment. At the end of the experiment, blood and urine samples were collected for routine and biochemical assays. The internal organs were taken for calculating their organ coefficients and histopathological examinations.


RESULTS
During the experimental period, no obvious abnormality were found in the experimental animals. The body weight and the total food availability rate in the high dosage group of male were lower than that of control (P < 0.05). Hematology examination showed that the quantity of Hb and RBC in high dosage groups of both the male and female and Hb in the male middle group were all lower than the control group (P < 0.01 or P < 0.05). Analysis of correlation indicated that r = -0.433, P < 0.01 in male, r = -0.337, P < 0.01 in female of Hb; r = -0.266, P < 0.05 in male, r = -0.317, P < 0.01 in female of RBC. There were obviously negative correlation. Serum biochemistry examination showed the concentration of CHO in the high and middle dosage treated rats of male and female were higher than that of the control (P < 0.01 or P < 0.05). Analysis of correlation indicated that r = 0.497, P < 0.01 in male, r = 0.417, P < 0.01 in female. No abnormality were found in urine examination. The organ weight and organ coefficient such as liver, were higher than control group (P < 0.01). The result of histopathological examinations displayed that the renal tubule Cast and the tubulointerstitial nephritis in the treated groups were higher than that of control group (P < 0.01).


CONCLUSIONS
97% ITX could obviously interfere with the animals' physical condition, and reduce the number of RBC and the concentration of Hb in the blood, interact metabolism of lipoid and induce the concentration of CHO in the serum. The livers of the treated rats are compensatory enlarged. And kidneys of the poisoning animals are damaged. The 2 years oral NOAEL of 97% ITX in rats are more than 4.63 mg/kg for female rats, and larger than 4.06 mg/kg for male rats.
Wang
Jing
J
Tianjin Center for Disease Control and Prevention, Tianjin 300011, China.
Wang
Xiao-jun
XJ
Yang
You-run
YR
Jiang
Wen-ling
WL
Zhang
Li
L
Xie
Yong-ling
YL
Zhang
Jing
J
Liu
Ying-hua
YH
Li
Xin
X
D000284:Administration, Oral; D000818:Animals; D005260:Female; D008297:Male; D019055:No-Observed-Adverse-Effect Level; D051381:Rats; D017208:Rats, Wistar; D036401:Toxicity Tests, Chronic; D044004:Xanthones / Q000633:toxicity*
D044004:Xanthones; C514852:isopropyl thioxanthone