骨化三醇对大鼠矽肺纤维化的干预作用及其机制
Intervention effect of calcitriol on silica-induced lung fibrosis in rats and relevant mechanism
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摘要:
目的 观察骨化三醇对大鼠矽肺纤维化的干预作用及其可能机制。
方法 将48只SD大鼠随机分为4组：对照组、模型组、溶媒组和骨化三醇组，每组12只。模型组、溶媒组、骨化三醇组采用非气管切开暴露法一次性支气管灌注二氧化硅悬液（50 mg/mL）1 mL构建大鼠矽肺模型，对照组大鼠同法注入等体积生理盐水。于造模当天开始每天给药，骨化三醇组给予蓖麻油稀释的骨化三醇（0.5 μg/kg）灌胃，溶媒组给予等体积蓖麻油灌胃，对照组及模型组给予等体积生理盐水灌胃。每组分别于造模后第14、28天随机处死6只大鼠。用HE染色、Masson染色法观察大鼠肺组织病理变化，碱水解法检测羟脯氨酸含量，免疫组化法检测大鼠肺组织中转化生长因子-β1（transforming growth factor-β1，TGF-β1）、SMA-和MAD-相关蛋白（SMA-and MAD-related protein，SMAD）3、SMAD7蛋白表达。
结果 骨化三醇组大鼠肺泡炎症细胞浸润、肺间质纤维化的程度较模型组明显减轻。与同期模型组大鼠相比，骨化三醇组大鼠肺系数、羟脯氨酸含量降低，差异均有统计学意义（P < 0.05），骨化三醇组TGF-β1（0.021 9±0.003 1）、SMAD3（0.036 9±0.001 6）蛋白表达量低于模型组（0.036 1±0.002 2）、（0.042 0±0.002 0）（P < 0.05），SMAD7（0.033 3±0.002 1）蛋白表达明显高于模型组（0.014 4±0.002 4）（P < 0.05）；模型组和溶媒组以上结果差异无统计学意义（P>0.05）。
结论 骨化三醇能减轻矽肺纤维化，这与其调控TGF-β1/SMAD通路中蛋白表达有关。
Abstract:Objective To explore the intervention effect of calcitriol on silica-induced lung fibrosis in rats and its possible mechanism.
Methods SD rats (n=48) were randomly divided into four groups:control group, model group, solvent group, and calcitriol group, with 12 rats in each group. Rats in the model group, solvent group, and calcitriol group were exposed to 1 mL silica particle suspension (50 mg/mL) intratracheally to establish silicosis rat model, while the control group was exposed to an equal volume of saline using the same protocol. Starting from the day of model establishment, the calcitriol group was given intragastric administration of castor oil-diluted calcitriol (0.5 μg/kg) daily, the solvent group was treated with an equal volume of castor oil, and the control group and the model group were given an equal volume of saline. Six rats of each group were sacrificed randomly at 14 and 28 days after modelling respectively. The pathological changes of lung tissues were observed by HE staining and Masson staining. The content of hydroxyproline was detected by alkaline hydrolysis. The expression of transforming growth factor-β1(TGF-β1), SMA-and MAD-related protein (SMAD) 3, and SMAD7 in lung tissues were detected by immunohistochemistry.
Results The calcitriol group showed alleviative lung inflammation and interstitial fibrosis than the model group. Compared with the model group, the pulmonary organ coefficients and hydroxyproline content were decreased in the calcitriol group (P < 0.05). The protein expressions of TGF-β1 (0.021 9±0.003 1) and SMAD3 (0.036 9±0.001 6) in the calcitriol group were lower than those in the model group(0.036 1±0.002 2) and (0.0420±0.0020) (P < 0.05), and the protein expression of SMAD7 (0.033 3±0.002 1) in the calcitriol group was higher than that of the model group (0.014 4±0.002 4) (P < 0.05). There were no significant differences in above in dicators between the model group and the solvent group (P>0.05).
Conclusion Calcitriol could alleviate silicosis fibrosis in rats, which may be associated with its regulation of protein expression in TGF-β1/SMAD pathway.
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