A MRI Study Of The Effect Of Sialic Acid Supplementation On Early Brain Development Of Piglets

Sialic acid is a term for the N-or O-substiruted based on parent compound, neuraminic acid which is a monosaccharide with a nine-carbon backbone. Sialic acids can be found in animal tissues and in other organisms mostly in glycoproteins and gangliosides. Sialic acid is widely distributed throughout human tissues, and the brain has the highest concentration in which they play an important role in ganglioside structure in synaptogenesis and neural transmission. Many experiments show that sialic acid play an important role in brain development, learning and memory abilities.The aim of this study is to investigate the effect of different forms of sialic acid on brain structrual development and congnitive development of the postnatal piglet, an perfect animal model of human infant.Sixty-one,3days old male piglets which were purchased from a commercial piggery were allocated to control (N=16), group1(N=14), group2(N=15) and group3(N=16). All piglets were fed on formula milk with different forms of sialic acid in each group from3-38after days following birth. During the age of22days to38days old, all piglets were subject to behavioral tests including open filed,8-arm maze cognitive training and woking memory test. All in vivo MRI were carried on a3T scanner in combination with a4-channel surface coil at the age of38days old and High-resolution T1images and diffusion tensor images of the brain were acquired. For T1images, voxel-based morphometry (VBM) was performed for local volum changes in gray matter. The corpus callosum in DTI image was divided into to three regions of genu, body and splenium. The fractional anisotropy (FA) value of this three regions were calculated by DTIstudio.VBM results between group1and control showed that significant increases in GM volume were observed in several brain regions of Dorsolateral motor cortex, Primary visual cortex and Cerebellar lobule, And a significant decrease in GM volume was observed in brain region of Colliculus superior (Two-sample t-test, cluster size>20, p<0.005). VBM results between group2and control showed that significant increases in GM volume were observed in several brain regions of insular cortex, somatosensory cortex, parahippocampal, superior temporal and cerebellar lobule, And a significant decrease in GM volume was observed in brain regions of Commisura anterior, substantia grisea centralis, claustrum and nucleus lateralis dorsalis thalami(Two-sample t-test, cluster size>20, p<0.005). VBM results between group3and control showed that significant increases in GM volume were observed in several brain regions of Thalami and Pharahippocampal cortex, And a significant decrease in GM volume was observed in brain region of Cerebellar lobule(Two-sample t-test, cluster size>20, p<0.005). DTI results showed that no significant difference between groups was observed(p>0.05).Based on the above experimental results, the conclusion summarized as below:(1) Sialic acid have no effect on piglet’s bodyweight, brain weight and brain volum.(2) N-acetylneuraminicacid supplementation increased gray matter volum in the following regions: Dorsolateral motor cortex, Primary visual cortex and Cerebellar lobule. Sialic acid-lactose supplementation increased gray matter volum in the following regions:insular cortex, somatosensory cortex, parahippocampal, superior temporal and cerebellar lobule. Protein-bound plus Lactose-bound supplementation increased gray matter volum in the following regions:Thalami and Pharahippocampal cortex.(3) Sialic acid have no effect on myelination process.