Abstract
The present study was performed to identify the factors influencing on early pregnacy and embryo implantation in rabbit. Serum, uterine fluid, and uterine tissue were collected on day 0, 3, 5, 7 and 9 of pregnancy. The intrauterine environment of receptive phase and refractory phase was compared by measuring protein synthetic capacity of endometrium, amino acid composition and concentrations of lipids(phospholipid, cholesterol). The results obstained were as follows : 1. The concentrations of total protein were significantly increased (p<0.01) on day 5 ($7.00{\pm}0.55$), 7($6.29{\pm}0.65$), and 9($6.34{\pm}0.61$), compared to those on day 0($5.50{\pm}0.12g/100m{\ell}$) in serum. The concentration of albumin on day 0 was $0.81{\pm}0.05$ and reached maximum on day 5 ($1.59{\pm}0.07g/100m{\ell}$) in serum. The concentrations of total protein were significantly increased(p<0.01) on day 5($1.56{\pm}0.10$), 7($1.99{\pm}0.22$), compared to those on day 0($0.38{\pm}0.02g/100m{\ell}$) in uterine fluid. The concentration of albumin on day 5($0.78{\pm}0.05g/100m{\ell}$) was higher than those on the other days in uterine fluid. 2. The incorporation rates of [$^3H$]-leucine into protein were significantly increased(p<0.01) on day 5 ($919.6{\pm}97.5$), 7($1445.4{\pm}95.9$) and 9($450.38{\pm}28.71$), compared to those on day 0($328.2{\pm}38.9cpm/mg$ protein) in endometrium. The incorporation rates in colehicine-treated endometrium on day 5 ($1341.9{\pm}73.8$), 7($1729.4{\pm}63.3cpm/mg$ protein) were significantly higher(p<0.01) than those on the other days. 3. The compositions of amino acid were not distinctly changed during early pregnancy in serum. The composition ratios of methione, lysine were distinctly decreased on day 3, compared to those on day 0 in uterine fluid. Those of glycine, alanine were increased on day 9, compared to those on other days but his tidine decreased in uterine fluid. 4. The concentrations of total phospholipid and total cholesterol were significantly decreased(p<0.01) on day 3($77.9{\pm}15.5$, $61.5{\pm}21.2$), compared to those on day 0($164.0{\pm}33.9$, $167.2{\pm}46.2mg/100m{\ell}$)in serum. The concentrations of total phospholipid and total cholesterol on day 9 ($47.3{\pm}13.4$, $37.7{\pm}9.6mg/100m{\ell}$) were significantly higher(p<0.01) than those on the other days in uterine fluid. 5. Total phopholipid/total cholesterol ratios were not significantly changed during early pregnancy in serum. However, total phospholipid/total cholesterol ratios on day 5 ($2.00{\pm}0.42$), 7 ($1.11{\pm}0.77$) and 9 ($1.47{\pm}0.30$) were higher than those on day 3($0.84{\pm}0.41$) in uterine fluid. 6. The concentrations of phosphatidylcholine and phosphatidylserine were significantly increased (p<0.01) on the other days, compared to those on day 0 during early pregnancy in serum. The concentrations of phosphatidylcholine were significantly increased(p<0.01),compared to those on day 0 and those of phosphatidyl-ethanolamine were consistently increased but not significant in early pregnancy in uterine fluid.