| Boron is an essential trace element involving in many physiological activities for animals. It is mainly absorbed into gastrointestinal tract, respiratory system is interlinked with the outside, and can be attacker by external stimuli frequently. The lung of Africa ostrich chicks are not developed completely, so that are vulnerable to pathogen invasion. By makes those chicks becoming susceptible animals of respiratory system disease, it shows a high mortality of brooding period ostrich chicks. Dozens of previous studies searching in the physiological funcations of boron have been reported, especially boron plays a role in bone, brain and immune organs forming and developing, or boron compounds in cancer treatment ect. However, how boron makes contributions to respiratory system has not been reported. In order to find out maximum tolerable dose of Africa ostrich chicks’ respiratory system, lung was selected as the research object in this study, different dose of supplemental boric acid in drinking water have been offered to indicate the effects of boron to lung. Newboron ostrich chicks were divied into 6 groups randomly. In each group, drinking water were in different concentration of boric acid, 0 mg/L(group A), 40 mg/L(group B) and 80 mg/L(group C), 160 mg/L(group D), 320 mg/L(group E) and 640 mg/L(group F), respectively, and was supplied uninterrupted for 90 days. Paraffin sections of lung of 90-day-old ostrich chicks in each group have been made at the end of the brooding period. HE and MASSON staining, SOD, MDA, GSH assay, TUNEL and quantitative real-time PCR, have been used for investigating different boron dose in drinking water having effects on the chicks’ lung development. 1 The effects of boron on morphological structure of ostrich lungHE staining was used as a preliminary assessment of lung and as a standard of quantitative analysis of lung pathological changes to determine the effects of boron. The results showed that compared to the control group(0 mg/L), lung structure were clear and well developed in group B, C and D(40-160 mg/L); on the contrary, in group E and F(320-640 mg/L), lung morphological structure were broken, number of heterophilic granulocytes were increased, blood vessels contained more lymphocytes, and intercellular space were wider. In this situation, the inflammation reponse obviously taken place, suspected pulmonary fibrosis. Obserbed under microscopy at high magnificantion(1000×, oil microscopy), in group E and F(320-640 mg/L), nucleus fragmentation have been show up, suggest that 320-640 mg/L supplemental boron may promote cell apoptosis of lung. 2 The effects of boron on ostrich serum antioxidant capacitySOD, MDA and GSH kit were used for detecting serum SOD activity, GSH and MDA level. The results indicate: compared with control group, SOD activity in 0-160mg/L boron dose showed an increasing trend, a significant difference was in 80 mg/L(P<0.05); but were decline in 320-640 mg/L, and in 640 mg/L had a significant difference(P<0.05); GSH content in 0-160 mg/L was increased, in 80 mg/L there was significant difference(P<0.05), the concentration of boron in 320-640 mg/L is on the decline and showed significant differences(P<0.05); MDA content in 0-160 mg/L boron doses group is on the decline, but had no significant difference(P>0.05), the concentration of boron in 320-640 mg/L are on the rise, it showed a significant difference of 640 mg/L(P<0.05). Comprehensive indicated that concentration of boron in 40-160 mg/L can improve SOD activity and GSH content, reduce MDA content in ostrich serum, then improve the body’s antioxidant capacity; the concentration of boron in 320-640 mg/L can reduce SOD activity and GSH content, improve MDA content, damage the body’s antioxidant capacity. 3 The effects of boron on inflammation of ostrich lungHE staining results illustrate that, in 320-640 mg/L, heterophilic granulocytes were increased, pulmonary inflammatory response. To lucubrate the results, detection IL-1β, IL-6, IL-10 m RNA expression level in lung tissue by quantitative real-time PCR. Compared with control group, IL-1β m RNA expression level was declined in 40-80 mg/L, and have a significant increased in 160 mg/L, and have a high significant increased in 320-640 mg/L. Compared with control group, IL-6 m RNA expression level was not significant change in 40-160 mg/L, and have a high significant increased in 320-640 mg/L. Compared with control group, IL-10 m RNA expression level was not significant change in 40 mg/L, and have a significant increased in 80-160 mg/L, and have a high significant increased in 320-640 mg/L. From the above, when the proinflammatory factor IL-1β, IL-6 cause inflammation, the anti-inflammatory factor IL-10 increased to confront excessive inflammatory reaction. Conclusion: If the concentration of boric acid in drinking water was 40-160 mg/L, it could inhibit inflammation, or else if the concentration of boric acid in drinking water was 320-640 mg/L would promote inflammation in lung. 4 The effects of boron on apoptosis of ostrich lungIt is known HE stained under high power microscope(1000×) observed in Group E and F(320-640 mg/L) lung cell nucleus were broken, so that if the concentration of boric acid in drinking water was 160-640 mg/L might increase cell apoptosis in lung. To confirm the conclusion, TUNEL, fluorescence microscope image snapping found that the boron concentration from 40 to 160 mg/L could inhibit apoptosis significantly, the boron concentration from 320 to 640 mg/L would promote cell apoptosis.To further confirm the correlation of Boron concentration with apoptosis, caspase-3 m RNA expression level were evaluated by real-time quantitative PCR. Compared to control group, the boron concentration of 40-160 mg/L caspase-3 m RNA expression level decreased significantly(P<0.05), the boron concentration from 320 to 640 mg/L caspase-3 m RNA expression level increased significantly(P<0.05). 5 The effects of boron on pulmonary fibrosis of ostrichMASSON staining marked collagen fibers and IOD valued statistical analysis. It was found that the boron concentration from 320 to 640 mg/L the number of collagen fibers were increased in lung, obviously. In this experiment, extracellular matrix(ECM) and epithelial-mesenchymal transition(EMT) for evaluation of pulmonary fibrosis. ECM, E-Cadherin, a-SMA and Vimentin m RNA expression level evaluated by real-time quantitative PCR. With the increase of boron concentration, ECM, a-SMA and Vimentin m RNA expression level was rising up, E-Cadherin m RNA expression level was declined. In a word, the effect of boron concentration 160 mg/L on pulmonary fibrosis was not obvious(P>0.05), boron concentration from 320 to 640 mg/L could lead to pulmonary fibrosis significantly(P<0.05).In conclusion, boron concentration from 40 to 160 mg/L could improve the serum antioxidant capacity, reduce lung inflammation response and cell apoptosis in African ostrich chicks’ lung, but no obvious effect on pulmonary fibrosis; Oppositely, boron concentration from 320 to 640 mg/L might put off serum antioxidant capacity, lead to inflammatory, cell apoptosis, and pulmonary fibrosis in African ostrich chicks’ lung. |
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