【Objective】 To investigate brain accretion of docosahexaenoic acid (DHA) at different ages and the expressional changes in related fatty acid desaturases (FADS). 【Methods】 3~4 weeks old C57BL/6J female mice were fed with two types of diets,n-3 PUFA deficient diet and n-3 PUFA containing diet.Followed by 6-week feeding,the mice were mated for breeding new pups.At postnatal 7 d,21 d and 42 d respectively,new pups were sacrificed and the blood,brain and liver were gathered.Fatty acids in the tissues were analyzed by gas chromatography and expressed as percent (%) of the total fatty acids.The mRNA expressions of FADS1 and FADS2 in the brain and liver were assayed by real-time RT-PCR. 【Results】 In both n-3 PUFA deficient and containing diet groups,the levels of DHA and total n-3 PUFAs increased in the brain and decreased in the liver with age increasing.Compared to the mice with n-3 PUFA deficient diet,the levels of DHA and total n-3 PUFAs in both the brain and liver at 7 d,21 d and 42 d were significantly increased in mice fed with n-3 PUFA diets.The percentage change in DHA level in the brain became minor with the age increased,whereas no differences were shown in the liver among the three ages.The levels of FADS1 and FADS2 mRNA were higher at 42 d than those at 7 d and 21 d in the brain,and no differences in FADS mRNA were found in the liver among the three ages.In mice with the n-3 PUFA diet,FADS1 and FADS2 mRNA levels were reduced in the brain at 7 d and 21 d with no changes at 42 d,and did not change at 7 d and 21 d with decreased level of FADS1 mRNA in the liver. 【Conclusion】 Brain accretion of DHA decreases and FADS expression increases with the age increasing.Diet n-3 PUFA deficiency affects brain accretion of DHA and the expression of FADS to a larger extent in an early age.
Key words
n-3 polyunsaturated fatty acids /
docosahexaenoic acid /
fatty acid desaturase /
brain /
mice
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