| IntroductionNanomaterials is referred to the particle size is 1nm-100nm nanometer powder, the diameter is 1nm-100nm nanometer thread and thickness is 1nm-100nm nanometer thin film, and appears a nanometer effect. With a dramatic development of nanometer technology, nanomaterials are widely applied in the multitudinous domains, so that the people will be able to have more opportunity to contact nanomaterials from now on. Because of the special effect of nanometer structure, nano-particles have possibility to enter the region which in organism the micron level granular materials cannot arrive in, and under the similar mass concentration, nano-particles also have higher quantity and activeness than micro-particles, so they will get more opportunity to response with cell, nano-particles will produce more tremendous influences to organism compared to ordinary pollutant particles, therefore, the safety evaluation of nanomaterials can't be neglected. Some research indicated that nano-particles could enter lung organization through the respiratory tract, depositing in each section of animal's respiratory tract and alveolus, initiating inflammation of lung, creating direct and indirect harm to lung macrophage, then induce lung granuloma production and fibrosis interstitial substance, long time high dose inhaled even can induce the animal tumor.The pulmonary toxicity research of nano-particles is still at the preliminary stage at present. Few of the empirical data is available and the research conclusion reproduction quality was bad. And the availability research mostly concentrates in non-toxic or min-toxic macroscopic material transforms to nanomaterials, which appears the toxicity or the toxicity strengthens, but the hypsi-toxic particles of silicon dioxide transforms to nanometer level its acute lung toxicity research are few. We selected nanometer and micrometer silicon dioxide as experimental material, in the aspects of the cell and the marker enzyme activity in BALF, hydroxyproline in serum and organization pathology of lung, compared with acute toxicity of pulmonary of nanosized and microsized powders of silicon dioxide and discusses the function mechanism.Materials and Methods(?). Animals and treatment150 healthy male Wistar rats, body weights were about 180-220g, were divided into 5 groups: blank control,nm-SiO, (?)m-SiO 100, 300mg/m group separately, there were 30 animals in each group. The volume of inhalation chambers is 100 liters. Wistar rats were exposed to particles of microsized and nanosized SiO by respiratory tract inhale two hours once. Choose 6 rats to carry on the experiment at random from every dosage group separately at 6h, 12h, 24h, 48h, 72h time points after inhale once.(?). Observation and determination1．The cell component examination in BALF(1) Cell total: erythrocytometry.(2) Cell classification: Geimsa, examination of microscopic.2．The biochemistry ingredient examination in BALF(1) Protein content determination: Coomassie bright orchid method determination.(2) LDH activeness determination: 2, 4-dinitro-phenyl-hydrazine method determination.(3) AKP activeness determination: The aminoantipyrine method determination. Above all kits were provide by the bio-engineering research institute of Nanjing.3．Lung organization pathology examinationThe lung is fixed by 10% paraformaldehyde, the paraffin wax embedding, slice thickness 5um, haematoxylin-eosin(HE) dyes, under microscope observes. 4．Data analysisThe variances were analyzed by software SPSS 13．0, all data were expressed in means(?)SEM. The normal distribution data were analyzed by One-way ANOVA; The non-normal distribution data were analyzed by Rank sum test. The results were regarded as significant as P < 0．05．Results1．The cell component change in BALFTCS in BALF of group nm-SiO100mg/m and 300mg/m at 6h were significantly higher than those in control group(P < 0．05) ; TCS in BALF of group nm-SiO100mg/m at 6, 24h were significantly higher than those in Isodose group of micro-sized SiO(P < 0．05) ; TCS in BALF of group nm-SiO300mg/m at 24h were significantly lower than those in group nm-SiO100mg/m(P < 0．05) .2．The total protein change in BALFTPr in BALF of group nm-SiO300mg/m at 6, 12, 48h, group (?)m-SiO100 and 300mg/m at 12h, group nm-SiO100mg/m at 48h and all experimental group at 24h were significantly higher than those in control group(P < 0．05) ; TPr in BALF of group nm-SiO100mg/m and nm-SiO300mg/m at 48h were significantly higher than those in Isodose group of micro-sized SiO(P < 0．05) .3．The activeness of LDH change in BALFLDH in BALF of group nm-SiO300mg/m at 6,24h and group nm-SiO100mg/m at 24, 72h were significantly higher than those in control group(P < 0．05) ; LDH in BALF of group nm-SiO100mg/m at 72h were significantly higher than those in Isodose group of micro-sized SiO and group nm-SiO300mg/m(P < 0．05) .4．The activeness of AKP change in BALFAKP in BALF of group nm-SiO300mg/m at 6,24h and group nm-SiO100mg/m at 24h were significantly higher than those in control group(P < 0．05) ; AKP in BALF of group nm-SiO300mg/m at 6, 24h were significantly higher than those in Isodose group of micro-sized SiO(P < 0．05) .5．Lung organization pathology morphology observationLung organizational structure of control group is normal, the pulmonary alveolus gap is thin, around the blood capillary has not seen the inflammatory cell to seep out, nearby the bronchial tube branch has certain lymphocyte, but this for rodentia animal lung normal tissue shape structure. (?)m-SiO group visible part pulmonary alveolus gap varying degree proliferation accumulation, partial pulmonary alveolus gap varying degree extravasated blood and obviously pale Iraqi red dropsy fluid; Around the trachea and the bronchial tube has the massive phlogocyte infiltration; Also the 300mg/m group compares the 100mg/m group to be serious. The nm-SiO group besides sees the above change, in lung organization partial pulmonary alveolus structure arrangement disorder or lung consolidation; Blood capillary lumen extravasated blood, periphery massive phlogocyte accumulation; The partial endobronchials have the mucous membrane epidermis accumulation which the massive red blood cells, the phlogocyte and fall off, its periphery has the massive phlogocyte accumulation; Pulmonary alveolus cavity and in accumulation pulmonary alveolus gap obviously massive phlogocyte infiltrations and so on granular cells and macrophage, but the dosage-effect relations is not obvious. Between the nanometer level SiO group lung the nature inflammation response micron level SiO group is heavy.ConclusionUnder the experiment conditions of present studies, nm-SiO and (?)m-SiO powder existence acute harm function to lung, there are some differences in acute pulmonary toxicity of nanosized and microsized SiO:1．Both nm-SiO and (?)m-SiO powder caused TCS in BALF obvious ascension after inhaled 6h, nm-SiO TCS ascension degree to be higher than (?)m-SiO in 6, 24 h 100mg/m dosage level.2．The nm-SiO powder causes the acute inflammation which leads to respond by NP and Lym, but (?)m-SiO does not have this function nearly.3．Both nm-SiO and (?)m-SiO powder may cause Tpr in BALF ascension, Tpr ascension degree nm-SiO is higher than (?)m-SiO in 48h.4．The nm-SiO powder causes activeness of LDH in BALF obvious set up in 24, 72h 100mg/m and in 6, 24 hour 300mg/m dosage level, comparison with the same dosage (?)m-SiO group has ascension tendency. But the change of (?)m-SiO group have no significance.5．The nm-SiO powder may causes activeness of AKP in BALF ascension in 6, 24h 300mg/m dosage level, also is higher than (?)m-SiO obviously; But (?)m-SiO group have no obviously changes.6．The nm-SiO powder may cause partial lung organization create pathology change, pathological change degree nm-SiO is heavyer than (?)m-SiO. |
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