孕期和哺乳期1，25-（OH）2D3干预对子代哮喘大鼠肺组织TGF-β1和Smad3表达的影响

Effect of 1,25-(OH)2D3 supplementation during gestation and lactation on TGF-β1 and Smad3 expression in lungs of rat offspring with asthma

摘要:

目的：探讨孕期和哺乳期1，25-二羟维生素D3［1，25-（OH）2D3］干预对子代哮喘大鼠肺组织中转化生长因子β1（TGF-β1）及Smad3表达的影响。方法：雌性Wistar大鼠32只，随机分为4组（n=8）：低剂量、中剂量及高剂量1，25-（OH）2D3干预组和对照组。受孕第7天起，以隔天灌胃的方式分别给予低、中剂量及高剂量组2、10、20 μg/mL 1，25-（OH）2D3，对照组以生理盐水代替，直到子代大鼠生后21 d断乳为止。制备子代大鼠哮喘模型。采用RT-PCR和免疫组织化学方法分别从mRNA和蛋白水平检测TGF-β1和Smad3的表达变化。结果：(1)各组仔鼠哮喘模型支气管炎症程度不同，与对照组相比，低、中剂量组炎症反应减轻，而高剂量组则加重。(2)免疫组织化学结果显示，与对照组相比，TGF-β1及pSmad3在低、中剂量组表达明显降低（P<0.05），而在高剂量组则表达明显增高（P<0.05）。(3) 荧光定量PCR结果显示，与对照组相比，低、中剂量组TGF-β1和Smad3 mRNA表达降低（P<0.05），而高剂量组两者的mRNA表达增高（P<0.05）。结论：在大鼠哮喘模型中，1，25-（OH）2D3可能通过维生素D受体信号通路，进而调节TGF-β/Smad信号通路相关蛋白的表达而发挥免疫调节作用。

Abstract:

OBJECTIVE: To study the effect of 1,25-(OH)2D3 supplementation during gestation and lactation on TGF-β1 and Smad3 expression in lungs of rat offspring with asthma. METHODS: Thirty-two female Wistar rats were randomly divided into four groups: low-, medium- and high-dose 1,25-(OH)2D3 supplementation and control groups (n=8 each). From the 7th day of gestation, the three 1,25-(OH)2D3 supplementation groups were administered with 2,10 and 20 μg/mL of 1,25-(OH)2D3 respectively every other day until weaning (rat offspring: 21 days old). The control group received normal saline instead. Then, bronchial asthma was induced in rat offspring from the 4 groups. The protein and mRNA expression of TGF-β1 and Smad3 in the lung tissue was measured by immunochemistry and RT-PCR. RESULTS: Eosinophil cell infiltration and airway inflammation decreased in rat offspring from the low- and medium-dose 1,25-(OH)2D3 groups, but increased in rat offspring of the high-dose 1,25-(OH)2D3 group compared with the control group. Immunohistochemistry of lung tissues showed that the expression of TGF-β1 protein and pSmad3 decreased in rat offspring from the low- and medium-dose 1,25-(OH)2D3 groups (P<0.05), but increased significantly in rat offspring from the high-dose 1,25-(OH)2D3 group compared with the control group (P<0.05). PCR showed that the expression of TGF-β1 and Smad3 mRNA in the lung tissue decreased in rat offspring from the low- and medium-dose 1,25-(OH)2D3 groups (P<0.05), but increased significantly in rat offspring from the high-dose 1,25-(OH)2D3 group compared with the control group (P<0.05). CONCLUSIONS: 1,25-(OH)2D3 supplementation plays a role in regulating the immune system in asthmatic rats. Its mechanism may be associated with regulation of the expression of TGF-β/Smad signal pathway-related proteins through the vitamin D receptor signal pathway.