Effects Of Intrauterine Growth Restriction During Late Pregnancy On The T Thymocyte Development Of Ovine Fetal Thymus And Gene Expression Involved

This study investigated the effects of intrauterine growth restriction on the thymocyte development and gene expression of ovine fetus during late pregnancy.6ewes out of42Mongolian ewes were slaughtered at the beginning of the experiment and the remaining36animals were allocated to three different groups:Restricted Group1(RG1,0.175MJ/kgw0.75·d-1, n=14), Restricted Group2(RG2,0.33MJ/kgw0.75·d-1, n=12) and Control Group (CG, n=10). At140d of gestation,6ewes in each groups were slaughtered as before.The results indicated:(1) With the reducing of maternal energy density during late pregnancy, the fetal weight (P<0.01), daily growth rate (P<0.01), body length (P<0.05), thoracic girth (P<0.05), abdomen circumference (P<0.05), straight crown-rumplength (P<0.01), curved crown-rump length (P<0.01) were significantly decreased compared to CG, and straight crown-rumplength (P<0.01) in RG1group was significantly decreased compared to CG.(2) The fetal red blood cell count (P<0.01), hemoglobin (P<0.01), hematokrit (P<0.01)、T-AOC (P<0.01)、SOD (P<0.05)were significantly decreased, while red cell distribution width (P<0.05)、mean platelet volume (P<0.05)、GSH-PH (P<0.05)、MDA (P<0.05) were greatly increased in RG1group compared to CG; The fetal mean platelet volume (P<0.05) were greatly increased, T-AOC (P<0.01) in RG2group was significantly decreased compared to CG(3)The fetal thymus weight, thymus cortical thickness, thymus DNA contents in RG1(P<0.01) and RG2(P<0.05) groups, and thymus cortical/medullary ratio, protein contents in RG1(P<0.01) were decreased compared to CG; The fetal thymus SOD (P<0.05)、 T-AOC (P<0.01) were significantly decreased, while GSH-PX (P<0.05)、MDA (P<0.05) in RG1group were greatly increased compared to CG.(4) The CD4+CD8+T lymphocyte subsets of fetal thymus were lower in both RG2and RG1(P<0.05), CD4+T lymphocyte subsets (P<0.01)were greatly increased in RG1group compared to CG; The CD4+、CD8+and CD4+/CD8+T lymphocyte subsets of fetal blood in RGl group were greatly decreased compared to CG.(5) With the decrease of maternal nutrition levels, for the development gene expression of fetal thymus, the expression levels of TCR, TCR1, TCR2, K5had the trend to decrease and the expression levels of K8genes trend to increase.