The Combined Effects Of Oxytocin And Estradiol Benzoate On Peripheral Blood Lymphocytes

The present study was to investigate the interaction between oxytocin and estrogen, andto study its mechanism.The cells pretreated were suspended in media containing either estradiol oxytocin (OXT)or estradiol benzoate (E2), or their combinations at a low, medial and high dose (the finalconcentration of OXT is10,100,1000ng/mL, the final concentration of E2is50,500,5000pg/mL) with concurrent treatment or pretreatment, and incubated with certainconcentration of Concanavalin A (Con A). Their response was then assessed by MTT assay todisplay the activity of lymphocytes proliferation, real time PCR and Western Blot to studyinteraction mechanism between OXT and E2. The results showed that, compared with thecontrol group, the SI values of different concentrations of oxytocin on resting lymphocyteswere respectively1.03±0.035;0.96±0.034;0.80±0.024, p=0.004; while activated cells wererespectively0.90±0.034, p=0.045;0.87±0.0056, p=0.008;0.77±0.036, p=0.002, whichindicated that oxytocin inhibited the proliferation of lymphocytes in a dose-dependent manner.High concentration of estrogen also inhibited proliferation of resting lymphocytes (SI value is0.92±0.011, p=0.037); With Con A stimulated, low dose of estrogen significantly stimulatedthe proliferation of PBMCs (SI value of1.15±0.090, p=0.023), however, high concentrationof estrogen performanced significant inhibition on PBMCs (SI value of0.83±0.062, p=0.004).When incubated with low or high dose of estrogen and oxytocin, the PBMCs are significantlyinhibited more strongly than the separately inhibitory effect (in high dose, for example, SIvalues of estrogen and oxytocin were0.92±0.011, p=0.034;0.80±024, p=0.006; while the SIof combined effects is0.62±0.060, p=0.001), which indicated the synergistic effects ofestrogen and oxytocin. When activated PBMCs were incubated with the physiologicalconcentration of the two hormones, the SI value was lower than the estrogen group and higherthan oxytocin group (SI value of estrogen and oxytocin group were separately1.10±0.040,p=0.021,0.95±0.024, p=0.046, while the SI of combined effect is0.97±0.036, p=0.065),which indicated the antagonistic effects of the two hormons. When activated lymphocyteswere successively processed by physiological dose of oxytocin and estrogen,12hOXT+E2 group stimulated lymphocyte proliferation, showing the effect of E2(SI value is1.08±0.016, p=0.043, similar to the SI value of estrogen, which is1.10±0.040, p=0.021).12hE2+OXT group inhibit the proliferation of lymphocytes, showing the effect of OXT (Its SIvalue is0.95±0.054, p=0.048, in accordance with oxytocin group, which is0.95±0.025,p=0.043), pointing out that these two hormones had "altruistic action" with each other.Physiological concentration of estrogen and oxytocin effected on ConA-stimulatedperipheral blood T lymphocytes, quantitative real-time PCR results showed that estrogen oroxytocin alone increased relative expression levels of ERα/OXTR mRNA. Compared with thecontrol group, E2group relative expression of ERα/OXTR mRNA were1.84±0.058,1.78±0.079, OXT group were1.58±0.10,1.41±0.080; Western Blot results were basicallyagreed with the former, E2/OXT also promoted the expression of ERα/OXTR protein levels,and the expression of ERα was significantly higher than OXTR. The combined combinedeffects of estrogen and oxytocin results showed that it displayed no significant effect on theexpression of ERα and OXTR mRNA or protein when estrogen and oxytocin added at thesame time;12hE2+OXT group12hOXT+E2group respectively stimulated the expression ofERα/OXTR mRNA and protein. Compared with control group, the expression of ERα/OXTRmRNA of12hE2+OXT and12hOXT+E2group were2.50±0.029,1.76±0.043;12hOXT+E2group was2.37±0.016,1.38±0.080, the relative expression levels of the protein were2.02±0.018,1.86±0.13;2.0±0.10,1.58±0.12; ERα/OXTR mRNA ratio were1.4,1.7,suggesting that12hE2+OXT group stimulated the expression of OXTR more strongly than12hOXT+E2group, the results showed that the "altruistic action" is relation to the expressionof ERα and OXTR.These resluts suggested that high dose of estrogen inhibited the function of lymphocytes,low doses of estrogen showed inhibition or stimulation effects on activated lymphocytes;oxytocin inhibited the function of lymphocytes. The combined effects of oxytocin andestrogen on lymphocytes were found to have antagonistic, synergy and "altruistic action "three modes, and the "altruistic action" is relation to the expression of ERα and OXTR.