Effects Of Intrauterine Growth Restriction During Late Pregnancy On Liver Cell Proliferation And Gene Expression Involved In Mongolia Ovine Fetus

This paper mainly investigated the effects of intrauterine growth restriction during late pregnancy on liver cell proliferation and gene expression involved in Mongolia ovine fetus. The techniques of synchronous estrus and artificial insemination were applied on 24 Mongolian ewes, which had similar live weight.6 ewes were slaughtered at 90 d of gestation and the remaining animals were allocated to three different groups: Restricted Group1 (RG1,0.175 MJME-BW-0075·d-1, n=6), Restricted Group2 (RG2,0.33 MJME·BW-0.75·d-1, n=6) and Control Group (CG, ad libitum,0.67 MJME·BW"0075·d-1, n=6). At 140 d of gestation,6 ewes in each group were slaughtered.(1) With the decreasing of the dietary energy density during late pregnancy, fetal liver weight and liver ADG were significantly decreased in RG2(p<0.05) and RG1(p<0.01)groups.The Col I concentration(p<0.01), ColⅢconcentration(p<0.05), Col IVconcentration(p<0.01), LN concentration (p<0.01), HA concentration (p<0.05) and FN concentration (p<0.01) was lower in RG1 groups than those of CG group, in addition, the FN concentration (P＜0.01) was decreased in RG2 group. The structure of liver was loose and liver cells were irregular arrangement. There were some reticular fibers and collagen fibers of the liver in RG2, RG1 groups were increased and became thickened in relation to CG group.(2) The total DNA content and protein/DNA were significantly reduced in RG2, RG1 groups when composed to CG group (p＜0.01). The percentages of G0-G1 phase cells in RG1 group(p<0.01) was significantly increased (p<0.05) when compared to RG2, CG groups; the percentages of S phase cells and proliferation index in RG1 (p<0.01),RG1 (p<0.05) group were significantly decrease (p<0.05) when compared to CG group.(3) The CyclinA (p<0.05) in RG2, RG1 groups were lower than those of CG group; the CyclinB, CyclinE in RG2, RG1 groups were lower than those of CG group (p<0.01), but the CyclinD in RG1 groups were highly than those of RG2 group p<0.05). The CDK1(p<0.05), CDK2(p<0.01), CDK4(p<0.01) in RG2,RGlgroups were lower than those of CG group. The reduction of E2F2 were greatly enhanced (p＜0.01) and the increasing of E2F5 were found (p<0.01) in RG1 groups composed to RG2, CG groups. The CDK1, CyclinD 1, E2F5 genes expression trend to up-regulation, whereas, the CyclinB 1, CDK4, E2Fltrend to down-regulationin CG, RG2 and RG1 groups.