孕期和生后维生素A缺乏及干预对幼鼠胫骨生长的影响

目的 探讨孕期和生后维生素A缺乏(vitamin A deficiency,VAD)及其补充对幼鼠长骨发育的影响.方法 健康成年雌性Wistar大鼠18只,分为5组.实验组母鼠及其仔鼠饲含维生素A 400 IU/kg、对照组及干预组于不同干预时间点改饲6 500 IU/kg饲料,实验持续至生后7周龄.各组子代鼠分别于生后0 d、4、7周分3批处死后称体质量、测胫骨长度,取血及骨样本待测,采用HPLC测血清维生素A水平、HE染色观测软骨组织形态学.结果 ①VAD组幼鼠的血清维生素A与正常组比较在生后0 d、4周和7周显著降低(P＜0.01).②VAD组幼鼠胫骨长度与正常组比较在生后0 d、4周和7周均明显变短(P＜0.01),至7周时,正常组与0 d补充组和胚补组比较无明显差别,而4周幼鼠干预组较正常组下降(P＜0.05),但仍长于VAD组(P＜0.05).③VAD组骺板软骨细胞增殖和钙化受到抑制,结构层次紊乱,同源细胞明显减少,软骨细胞陷窝小,核分裂象少且多幼稚.结论 维生素A缺乏对大鼠的软骨细胞发育有明显的影响,给予维生素A干预时间越早其纠正骨发育障碍的作用越有效.

Effects of vitamin A deficiency and its supplementation on tibial growth in rats

Objective To study the effects of vitamin A deficiency(VAD)and its supplementation on the skeletal growth in rats.Methods Eighteen female Wistar rats were randomly divided into VAD(Vit A 400 IU/kg diet,n=3),supplement(n=9)and control groups(normal diet Vit A 6 500 IU/kg,n=6).The supplement groups were randomly divided into 3 sub-groups,and their diet was changed to Vit A 6 500 IU/kg diet from 14 d after pregnancy,0 d and 4 weeks after birth respectively until they were 7 weeks age old.When they were 0 day,4 and 7 weeks old,their body weight,the length of the tibia,serum Vit A level were measured,and the histology of growth plate was also observed.Results At every measuring times,the serum Vit A level was significantly lower,and the tibial length was shorter in VAD group than in the control(P<0.01).For the tibial length,the pregnant and 0 d subgroups had kept up with the control until 7 weeks old,but that of the 4 weeks subgroup was still shorter than the control(P<0.05),while longer than that of the VAD groups(P<0.05).The histology of epiphyseal plate of the rats in VAD group showed disordered structure,and inhibited cartilage cell proliferation and calcification,with obviously reduced cell number,lesser and immature karyokinesis.Conclusion VAD has profound effect on the development of cartilage cells,and the earlier the supplement begins the more effective it will be.