The Effect Of Semen On Immune And Uterine Development To Pregnancy In Female Rabbits

In livestock, the difference between natural mating and embryo transfer is that the uterus of recipient in the later didn't touch semen. Therefore, the study on the effects of semen on development of uterus to pregnancy and immunity is useful to improve embryo transfer technique and contribute to the effective use of animal semen components.In the condition of ligation of the cervix, both uterine horns in rabbit were injected with physiological saline and semen, or sperm and seminal plasma, the effects of semen, sperm and seminal plasma on the development of uterus to pregnancy and immunity were studied. Thirty-two female rabbits were randomly assigned into four groups with equal number in each group. In group 1, each rabbit was injected with physiological saline (as control) into one side of uterine horn and semen into the other side of uterine horn. In group 2, group 3 and group 4, each rabbit was injected with sperm into one side of uterine horn and seminal plasma into the other side of uterine horn. The rabbits in group 1were killed 48h after injection. The rabbits in group 2, group 3 and group 4 were killed 48h, 72h or 148h after injection, respectively. The uteruses from the rabbits were made into tissue slice, the pictures were analyzed by image gathering system. The results are as follows:1.Compared with control group, the size of uterus significantly increased in semen group after 48h (P<0.05 or P<0.01), the length of uterine horn, the diameter of uterine horn and the index of uterine horn in semen group were 6.93±0.32cm, 0.90±0.04cm and 0.45±0.03 respectively, while those in control group were 5.58±0.30cm, 0.80±0.05cm and 0.31±0.01 respectively. The thicknesses of uterine wall(P<0.05), mucosal epithelium(P<0.01) and mucous membrane(P<0.05) significantly increased in semen group, they were 1.92±0.03mm, 2.06±0.2μm and 1.51±0.02mm respectively, while those in control group were 1.54±0.02mm, 1.55±0.03μm and 1.15±0.01mm respectively. The numbers of glandular tube (P<0.05) and blood vessel (P<0.05) in unit area and the thickness of glandular epithelium (P<0.05) significantly increased in semen group, they were 11.75±0.27/mm~2, 1.66±0.13/mm~2 and 1.65±0.03μm, respectively, while those in control group were 10.0±0.56/mm~2, 1.34±0.07/mm~2 and 1.39±0.06μm, respectively.2.From the index of uterine horn, length of uterine horn, thicknesses of uterine wall, mucous membrane, mucosal epithelium and myometrium, and the number of blood vessel, we found that the injection of seminal plasma were better for the development of uterus than that of sperm(P<0.05 or P<0.01), it showed that the seminal plasma was the major constituent in semen on promoting the development of uterine wall and blood vessels in mucous membrane. Whereas, there was no significant difference(p>0.05) between seminal plasma and sperm on the number of glandular tube, the thickness of glandular epithelium and the diameter of glandular tube, it indicated that seminal plasma and sperm had similar function on the development of mucous glands.3.In 148h after the injection of seminal plasma and sperm into the uterus, the uterine horn turned longer, the uterine wall and myometrium turned thicker, the numbers of mucous gland and blood vessel increased, the glandular epithelium turned thicker, and the diameter of glandular tube turned larger.4.The number of mast cells(MC) in endometrium obviously reduced in semen group(P<0.05), it was only 2.85±0.05/mm2, while that in control group was 3.72±0.04 /mm2. Compared with sperm, the seminal plasma was more effective to reduce the number of MC, and MC further reduced over time5.The volume of uterine flushing fluid significantly increased(P<0.05) in semen group. The effect of seminal plasma was more obvious than that of sperm. The volume of uterine flushing fluid was 0.76±0.19ml in seminal plasma group, but it was only 0.55±0.12ml in sperm group, there was a significant difference (P<0.05) between seminal plasma and sperm group. In addition, the number of cells in uterine flushing fluid significantly increased after the injection of semen (P<0.01), it was 53.3±4.03×109/L, while that in control group was 8.87±0.36×10~9/L. Compared with seminal plasma group (29.73±2.71×10~9/L), the number of cells in sperm group(45.16±4.20×10~9/L) was significantly higher (P<0.01). Smear examination of uterine flushing fluid revealed that the cells in uterine flushing fluid were mainly neutrophils.This study show that the semen injected into uterus can not only definitely promote the development of uterus to pregnancy and uterine secretion but also change immunity of endometriums.