Objective:To study the effects of marginal vitamin A deficiency (MVAD) on the hippocampal CA1 long-term potentiation (LTP) in young rats. Methods:Six female rats were divided into two groups at random, three in MVAD group, three in control group. The rats were fed VA deficient diet (400IU VA/kg) and VA sufficient diet (6 500IU VA/kg) respectively since 3 w before coitus. Serum VA was assessed by high performance liquid chromatography (HPLC). The young rats were killed at D49. The hippocampal CA1 LTP was detected by electrophysiological technique and the ultrastructure of synapses was observed by electron microscope. Results:The changes of field excitatory postsynaptic potentials (fEPSP) slope (25.4%?2.01%) in MVAD young rats aged 7 weeks were much lower than that in control group (57.5%?8.63%). The changes of slope of fEPSP induced by MVAD in young rats could be replenished after adding retinoic acid (P0.05). The curvature in synaptic interface of MVAD group was less than that of the MVAD supplemented RA group and the control. Conclusion:MVAD during embryonic and early postnatal period can directly impair the hippocampal CA1 LTP of young 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

BACKGROUND: Vitamin A deficiency disorders (VADD) is a healthy problem of children in the world, especially in the west of China and remote areas, and the nutritional intervention is needed.OBJECTIVE: To compare the improved effects of biscuits fortified with three different doses of vitamin A on the vitamin A status in children aged 3-6 years and explore ap ideal dose of vitamin A supplement for preventing VADD.DESIGN: Randomized controlled observation.SETTING: Health Surveillance Institute, Chongqing Municipal Health Bureau; Staff Room of Nutrition and Food Hygiene, College of Public Health, Chongqing University of Medical Sciences; Center for Children Nutrition, Children's Hospital, Chongqing University of Medical Sciences.PARTICIPANTS: The investigation was done between March and December 2002. 753 children aged 3-6 years from 8 kindergartens in Banan district of Chongqing city were enrolled with the agreement of their guardians. They were divided randomly into 4 groups: 30% recommended intake group, 100% recommended intake group, 20 000 international unit (IU) and 200 000 IU groups.METHODS: ① The biscuits fortified with 30% recommended intake of vitamin A (500 IU) were once given to people of the 30% recommended intake group (177 cases) every day. ②The biscuits fortified with 100% recommended intake of vitamin A (1666 IU) were once given to people of the 100% recommended intake group (173 cases) every day. ③The biscuits fortified with 20 000 IU of vitamin A were once given to people of the 20 000 IU group (209 cases) every week. ④The soft gelatin capsule with 200 000 IU of vitamin A were once given to people of the 200 000 IU group (194 cases).Height, body mass, serum retinal, prealbumin, haematoglobin and retinal binding protein of all children were measured before intervention and after intervention for 3 months. Above indexes were rechecked after supplement for 9 months in 87 children of 30% recommended intake groupMAIN OUTCOME MEASURES: ①Prevalence rate of VADD before in-tervention and after intervention for 3 months in children of every group.② Serum retinal, serum prealbumin, serum retinal binding protein,haematoglobin, height and body mass of children before intervention and after interventional for 3 months in every group.RESULTS: Because of lose of samples and detective technology, only 580 children' examination results were got by rechecking. ①Comparison of the prevalence rate of VADD of children in every group: Three months supplementation later, the prevalence of VADD in every group all decreased sig nificantly [1.48%,1.42%,1.21%, 2.16% ;6.78%,6.54%,8.61%,8.25%(χ2=3.86-8.57, P ＜ 0.05-0.01 )]. ②Comparison of serum retinal, serum prealbumin, serum retinal binding protein, haematoglobin, height and body mass of children of every group: After supplement for 3 months, except prealbumin and haematoglobin in the 30% recommended intake group ,other indexes in each group all increased significantly (t=2.52-37.44, P＜ 0.05-0.01 ). The increase of serum vitamin A in the 20 000 IU group was larger than that in the other groups (F=4.62,P＜ 0.01 ). The increases of haematoglobin, prealbumin and height in the 30% recommended intake group were less than those in the other groups (F=5.04-7.78 ,P ＜ 0.01 ).After supplement for 9 months, the increases of haematoglobin and prealbumin in the 30% recommended intake group were larger than those in the other groups (F= 11.62,10.21 ,P ＜ 0.01). The increase of serum retinal was still lower than that in the 20 000 IU group (F=4.21 ,P ＜ 0.01 ).CONCLUSION: Supplement with biscuits fortified with 3 different doses of vitamin A and capsule with 200 000 IU of vitamin A can improve obviously the nourished status of vitamin A and the level of ferrohemoglobin, in which 30% recommended intake and 100% recommended intake have small risk, and everyday supplement can maintain stably the level of vitamin A. That may be suitable for the long-term supplement for children, and the effect of 30% recommended intake was better than that of 100% recommended intake.