Effect Of Oxytocin On The Expression Of SYP In Bovine Luteal Cells

In order to research the expression of synaptophysin (SYP) and Its mRNA duringdifferent stages of pregnancy, and the effect of oxytocin (OT) on the expression of SYP,reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization (ISH)were used to confirm the expression of SYP mRNA in bovine corpus luteum (CL). Then SYPand Its mRNA during different stages of pregnancy were detected by immunohistochemistryand RT-PCR. The result analysed the correlation of SYP and OT, providing the basis for thefollowing research. The cultured bovine CL cells were treated by OT at different dose, andobserved the effect of OT on the cell growth and progesterone production, then detected theexpression level of SYP and Its mRNA to discuss their relationship. Now all the experimentalresults were showed as follows.1. SYP mRNA was expressed in bovine CL, and the expression level was differentduring different periods. The expression level was high during early and mid pregnancy, anddropped during late pregnancy. These showed SYP may participate in the formation andmaintenance of CL, and regulate the productions of proteins, hormones and cytokines. Afterparturition, the expression level increased. That maybe concerned with many proteins andfactors related apoptosis when the CL was degenerate.2. SYP was expressoned during different periods. The Immune positive reaction wasmostly found in large CL cells, and it was week or negative in small CL cells and otherovarian tissue. The expression was highest during all the pregnancy periods. These showedthat SYP was closely connected to the formation and maintenance of CL, and regulated thegrowth of CL.3. Different concentration of OT can restrain progesterone production in the cultured CLcells. The effect of low concentration was small, yet the high concentration can restrainsignificantly. The result was coincident with the cell viability by MTT. These expained thatOT can affect the cell viability and progesterone production, and the viability was correlativewith the concentration of progesterone in the culture solution. However, the effect of OT onthe progesterone production was related to the species, the period of CL and the concentrationof OT. 4. OT also affected the expression of SYP and its mRNA. The result by RT-PCR showeddifferent concentration of OT can promote the expression of SYP mRNA to different degrees.And the result by Western Blot showed OT can promote the expression of SYP markedly in adose dependent pattern.In summary, the expression of SYP and Its mRNA during different stages of pregnancywas a dynamic process, and it's highest during mid pregnancy. In cultured bovine luteal cellsof mid pregnancy, OT effected the cell growth, progesterone production and the expression ofSYP, and it's a positive correlation between the cell growth and concentration of progesterone.These exposited the new theoretical basis on the formation, apoptosis and degradation of CL,also the maintenance of pregnancy. As well, it provided the foundation for the mechanism ofOT to impact on the SYP expression.