The Effect Of Mitochondrial Activity In Granulosa Cells And L-Carnitine Level On The In Vitro Fertilization-Embryo Transfer

OBJECTIVE: The aim was to study the effect of mitochondrial activity in the granulosa cells on the quality of oocytes,embryos and the outcome of IVF-ET.To investigate the correlation of plasma and follicular fluid carnitine leverl wih mitochondrial activity in the granulosa cells. Determine the effects of the carnitine level on the IVF-ET.MATERIALS AND METHODS: The study was carried out between December 2008 and March 2009 in our reproductive center .We enrolled 63 normally cycling women undergoing IVF-ET programme for tubal factor infertility:the women with endometriosis or endocrine diseases and those with male factor infertility were excluded. All 63 patients underwent a long GnRH agonist protocol for pituitary down regulation followed by controlled ovarian hyperstimulation with rFSH and HMG.We collected follicular fluid at the ovum pick-up day,which seem no contamination by blood .Levels of free L-carnitne were measured by high performance liquid chromatography with pre-column ultraviolet durivazation. We also collected all the follicular fluid to isolate granulosa cells by gradient centrifugation,and the mitochondrial activity was sudied by flow cytometry using JC-1.All objects were classified to pregnant and non-pregnant group based on the out come of IVF-ET. Compared plasma L-carnitine and follicular fluid L-carnitine levels and mitochondrial activity of granulosa cells between pregnant and non-pregnant group,and examine the correlation among the three parameters and age ,the number of retrieved oocytes, fertilization,cleavage, good-embryo rates and themselves.RESULTS:1.The clinical pregnancy rate was 38.98%.The mean age was 32.24±4.14 years,the mean mitochondrial activity was 85.04±10.25%,the mean plasma free L-carnitine level was 34.23±7.74μmol/L,the mean follicular fluid L-carnitine level was 24.34±7.08μmol/L.2.Pregnant patients showed significantly higher mitochondrial activity (89.10±7.24% vs 83.22±11.05%,P<0.05) in granulose cells,lower plasma L-carnitine level(30.82±7.10μmol/L vs 35.69±7.28μmol/L,P<0.05),lower follicular fluid L-carnitine level(21.33±5.83μmol/L vs 26.07±5.46μmol/L,P<0.05).3.A declined mitochondrial performance had been observed during aging(r=-0.449,P=0.001),which had positive correlation with the number of retrieved oocytes,nomal fertilization rate and good-embyo rate(P<0.05).4.A positive correlation was seen between plasma L-carnitine level and age(r=0.467,P=0.002).A negative correlation was seen between L-carnitine level and mitochondrial activity and the number of retrieved oocytes. No correlation was seen among L-carnitine level and others parameters of IVF-ET(P>0.05).5.Follicular fluid L-carnitine level increased with plasma L-carnitine level,but had no significance(P>0.05).CONCLUSION:1.The mitochondrial activity in granulosa cells may effect the development of oocytes . 2.Perhaps the mitochondrial activity in granulosa cells can become the indicator of the quality of embryo.3.The poor outcome of IVF-ET of aged women may due to decrease of mitochondrial activity in granulosa cells.4.L-carnitine level increased with age.5.High L-carnitine level in plasma and follicular fluid may be identified as feedback of increased oxidative stress in women undergoing IVF-ET.