| Objective:To observe the effect of vitamin D deficiency and appropriate 1,25-(OH)2D3 intervention during pregnancy and lactation period of female rats on the lung development and pulmonary VEGF?SP-C expression of newborn rat,investigating the role of vitamin D deficiency and intervention in neonatal rat lung development and the underlying mechanism.Method:The clean grade of healthy adult female Sprague-Dawley rats were randomly divided into normal control group(control group),Vit D deficiency group(deficiency group)and 1,25-(OH)2D3 intervention group(intervention group),6 rats in each group.The control group and the intervention group were given normal diet and normal light,while the deficiency group were treated with diet lack of Vit D,away from light.After 2 weeks,serum 25-(OH)D of maternal rats in three groups were detected by ELISA,and then female rats in 3 groups copulated with normal adult male SD rats.From the 7th days of pregnancy to 21 st days after delivery,the intervention group were treatment with 1,25(OH)2D3(10?g/kg)every other day by intragastric administration,the control group and the deficiency group were given normal saline 1ml by gavage.In the three groups,serum 25-(OH)D of maternal rats at 21 st days after birth and newborn rats at the first day and 21 st days were detected again by ELISA.Rat lung tissue in newborn rats from each group was extracted on day 1?7?14 and 21 respectively,the following indicators were observed: 1.Newborn rats weight and lung wet weight;2.Observation of lung morphology by light microscope;3.The expression of VEGF mRNA level in the lung tissue was detected by q-PCR.4.VEGF and SP-C protein expression was detected in lung tissue by Immunohistochemical staining.Result:1.Modeling results: through different ways of feeding for 2 weeks,the difference of the maternal rats serum 25-(OH)D value ratio among the three groups was not statistically significant(P>0.05);21 days after delivery of rats,maternal serum 25-(OH)D value of deficiency group was significantly lower than that of the control group and intervention group rats(P<0.01);maternal serum 25-(OH)D value of intervention group was higher than that of the control group,the difference was statistically significant(P<0.05).The difference of the newborn rats serum 25-(OH)D value ratio among the three groups at the first day was not statistically significant(P>0.05);the difference of newborn rats serum 25-(OH)D value of deficiency group at 21 st days was lower than that of the control group and intervention group rats(P<0.05);newborn serum 25-(OH)D value of intervention group was a bit higher than that of the control group,but the difference was not statistically significant(P>0.05).2.Results of newborn rats weight and lung wet weight: with age increased,body weight and lung wet weight of the deficiency group rats were lower than those of the same age in the control group rats,and the growth speed was slow.Compared with control group newborn rats,the difference of body weight value in deficiency group at 14 th and 21 st days was statistically significant(P<0.05).The difference of lung wet weight of deficiency group at 7th,14 th,21st days was statistically significant compared with the control group rats(P<0.01).Body weight and lung wet weight of intervention group rats were higher than those of the same age in the control group rats,the growth rate was slightly greater.The difference of the body weight value showed a significant difference compared with control group rats(P<0.05,0.01).Compared with the control group rats,the difference of lung wet weight value at 14 th and 21 st days of intervention group rats were statistically significant(P<0.05).3.HE staining results of newborn rats in three groups observed by light microscope: the lung tissues of deficiency group rats had less number of pulmonary alveoli,smaller alveolar cavity,were more irregular and more thickened alveolar septum compared with control group rats of the same age.In lung tissue of intervention group rats,alveolar numbers increased,alveolar cavity size was uniform,solid slug structure region reduced and alveolar septum was thinner,compared with the same age of control group rats.4.Results of VEGF mRNA expression detected by q-PCR in lung tissues of the three groups: with the increase of age,VEGF mRNA expression in the control group and intervention group rats increased gradually.VEGF mRNA expression of the newborn rats at the first day after birth in the deficiency group was higher than that of control group and intervention group rats,the difference was statistically significant(P<0.05,0.01).VEGF mRNA expression decreased at 7th days after birth,the value was significantly lower than the control group and the intervention group(P<0.01).Then with the age increased,the expression gradually increased,the growth rate was slower compared with the control group and the intervention group and the growth cross was cross with the control group and intervention group.VEGF m RNA expression of intervention group increased slightly faster than the control group,expression levels were higher than the control group,the difference was statistically significant(P<0.05,0.01).5.Results of VEGF protein expression detected by immunohistochemical staining in neonatal rats lung tissues of the three groups: VEGF protein expression in the control group and intervention group rats increased gradually.VEGF protein expression of the newborn rats at the first day after birth in the deficiency group was a bit higher than that of control group and intervention group rats.VEGF protein expression decreased at 7th days after birth,the value was significantly lower than the control group and the intervention group(P<0.05,0.01).Then with the age increased,the expression gradually increased,the growth rate was slower compared with the control group and the intervention group.VEGF protein expression of intervention group increased slightly faster than the control group,expression levels were higher than the control group,the difference at 14 th and 21 st days was statistically significant(P<0.05).6.Results of SP-C protein expression detected by immunohistochemical staining in neonatal rats lung tissues of the three groups: with the increase of age,SP-C expression in newborn rat lung tissue increased gradually,SP-C expression of the deficiency group were lower than control group and intervention group rats,the difference was statistically significant(P<0.05,0.01);expression of SP-C of newborn rats in intervention group was higher than the control group rats,the difference at 14 th and 21 st days was statistically significant(P<0.05).Conclusion:1.Vit D deficiency during pregnancy and lactation period inhibits lung development of neonatal rat,proper amount of 1,25-(OH)2D3 intervention will be helpful in the development of rat lung.2.Vit D deficiency and proper supplement of 1,25-(OH)2D3 during pregnancy and lactation period may play a role in the lung development through regulating the expression of VEGF and SP-C in lung of offspring rat. |
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