[Comparative study on the acute toxicity of pulmonary caused by nanosized and microsized powders of silicon dioxide].
OBJECTIVE
To compare the acute pulmonary toxicities of nanosized and microsized silicon dioxide particles.


METHODS
All 125 healthy male Wistar rats were divided into 25 groups randomly according to the weight. Experimental animals were exposed to microsized SiO2 at the doses of 100 mg/m3 (group A) and 300 mg/m3 (group B), and to the nanosized SiO2 at the same dose levels (group A' and B') by inhalation for 2 hours. Compositions in bronchoalveolar lavage fluids (BALF) and contents of hydroxyproline in blood sera and lung tissues were detected and then compared at 6, 12, 24, 48, 72 hours after administration.


RESULTS
The total cellular score (TCS) in BALF of group A'[(55.00 +/- 8.30) x 10(4)/ ml] and B'[(52.50 +/- 9.02) x 10(4)/ml] at 6 hours were significantly higher than those in control groups [(34.88 +/- 12.53) x 10(4)/ml]; TCS in BALF of group A' [(55.00 +/- 8.30) x 10(4)/ml]at 6 hours and group A' [(39.75 +/- 12.08) x 10(4)/ml] at 24 hours were significantly higher than those in isodose group of microsized SiO2 [(32.38 +/- 13.07) x 10(4)/ml, (24.13 +/- 10.97) x 10(4)/ml) ]; total protein (TPr) in BALF of group A' [(0.34 +/- 0.09)g/L] and B' [(0.38 +/- 0.16) g/L] at 48 hours were significantly higher than those in isodose group of microsized SiO2 [(0.20 +/- 0.07) g/L, (0.21 +/- 0.05) g/L]. Lactate dehydrogenase (LDH) in BALF of group A' [(1.66 +/- 0.22) x 10(3) U/L] at 72 hours were significantly higher than those in isodose group of microsized SiO2 [(1.38 +/- 0.17) x 10(3) U/L]. Alkaline phosphatase (AKP) in BALF of group B' [(5.14 +/- 1.47) U/100 ml] at 6 hours and group B' [(5.86 +/- 2.41) U/100 ml] at 24 hours were significantly higher than those in isodose group of microsized SiO2 [(3.64 +/- 0.36) U/100 ml, (3.30 +/- 2.19) U/100 ml]. Hydroxyproline (HyP) in tissues of lung of group A' [(0.532 +/- 0.053) microg/mg, (0.484 +/- 0.046) microg/mg, (0.591 +/- 0.096) microg/mg, (0.551 +/- 0.084) microg/mg] at 6, 12, 48, 72 hours and group B' [(0.508 +/- 0.081) microg/mg, (0.565 +/- 0.053) microg/mg ] at 12, 72 hours were significantly higher than those in isodose group of microsized SiO2 [(0.345 +/- 0.074) microg/mg, (0.368 +/- 0.095) microg/mg, (0.431 +/- 0.036) microg/mg, (0.399 +/- 0.080) microg/mg, (0.396 +/- 0.039) microg/mg, (0.465 +/- 0.062) microg/mg].


CONCLUSIONS
Nanosized and microsized SiO2 should have some differences on acute pulmonary toxicities in our experiment condition.
School of Public Health, China Medical University, Shenyang 110001, China.
Jing
J
Wang
Yi-He
YH
Jin
Bing
B
Liu
Qi-Lin
QL
Yu
Ke
K
Wang
Cui-Xia
CX
Zhao
D000818:Animals; D001992:Bronchoalveolar Lavage Fluid; D004391:Dust; D008168:Lung / Q000187:drug effects*; D008297:Male; D053758:Nanoparticles; D010316:Particle Size; D051381:Rats; D017208:Rats, Wistar; D012822:Silicon Dioxide / Q000633:toxicity*; D023382:Toxicity Tests, Acute
D004391:Dust; D012822:Silicon Dioxide