Expression of TNF-alpha mRNA, but not of TNF-alpha receptors mRNA, is detected in single murine oocyte and decreases during oocyte meiotic maturation: single-cell RT-PCR data.

BACKGROUND: The present study was conducted to investigate the expression of TNF-alpha and its receptors (types I and II) in both oocytes with germinal vesicle and the first polar body in mice. METHODS: Oocytes with intact germinal vesicle were isolated from mouse ovaries and subjected to in vitro maturation to obtain oocytes forming the first polar body. A reverse transcription polymerase chain reaction (RT-PCR) was used to examine the expression of TNF-alpha and its receptors at mRNA level. RESULTS: mRNA TNF-alpha was expressed in single oocytes and its level was decreasing during transition from germinal vesicle to the first polar body stage. At the same time the expression of TNF-receptors was not observed in single oocyte. CONCLUSIONS: These data are the important link in understanding of the molecular mechanisms regulating oocyte maturation as well as follicle development.

[Regulation of oocyte meiotic resumption in mammals].

Currently, the molecular mechanisms involved in induction of oocyte meiotic resumption in the pre-ovulatory follicle which may include (involve) the elimination of meiosis inhibiting factors and/or the accumulation or activation of oocyte maturation signals are actively studied. The present review summarizes the existing literature data regarding the participation of cyclic monophosphates (cAMP and cGMP), protein kinases (mitogen-activated protein kinase (MAPK), AI, AII, B, C, G), epidermal-growth factors (EGF), EGF-like factors, mRNA EGF and EGF-like factors, ovarian steroid hormones and sterols, as well as transcription factors NF-kappaB and CREB (cAMP response element binding protein) in the regulation of mammalian oocyte meiotic resumption. Such scheme of regulation of oocyte meiotic resumption is discussed (considered): the action ofgonadotrophins, FSH and LH, causes increase the production ofcAMP and subsequent activation of MAPK. cGMP (during follicular growth) can prevent untimely oocyte meiotic resumption up to ovulation (after LH surge, after increase in LH). FSH- and the LH -induced system of EGF, steroids and sterols are involved in MAPK activation. Whereas different FSH and LH effects on NO production in ovary are involved in the regulation of induction of oocyte meiotic resumption in mammals. The further research is needed to better understand the new important mechanisms that regulate difficult aspects of oocyte meiotic maturation in mammals.

[Production of immunoregulatory cytokines in autoimimune damage of the ovaries in mammals].

Several ovarian disorders in women are associated with autoimmune factors. In this study it was investigated a level of cytokines--TNF-alpha and IFNs in ovarian homogenate and blood serum at ovarian autoimmune damage of mammals. Experimental immune ovarian failure was induced in CBA mice by either immunization with allogenic ovarian extracts or administration of xenogenic anti-ovarian antibodies. Both models were accompanied with abnormalities in production of immunoregulatory cytokines. These data confirm the importance of definition of proinflammatory cytokine level for disclosing immune mechanisms which lay in a pathogenesis autoimmune ovarian diseases of female reproductive organs.

[Cytokines and their role in reproductive system].

In this review we analyze the involvement of cytokines in regulation of ovarian function. A growing body of evidence suggests that the ovary is a site of inflammatory reactions. Immune-competent cells present within the ovary may constitute potential in-situ modulators of ovarian function that act through local secretion of regulatory soluble factors cytokines. In addition many over cell in the ovary also produce cytokines independently of the presence of leukocytes, thus ovaries are sites of cytokine action and production. There are many evidences that cytokines are involved in the ovarian control of follicular development and are surveyed as the important regulators of steroidogenesis and gamete production. It is established that cytokines generally inhibit gonadotropin-stimulated production of steroids. However ovarian steroids, in turn, reduce the cytokine production by immunecompetent cells. There are some data about participation of cytokines in regulating the proliferation and differentiation of granulose cells. Most cytokines appear in mammalian follicles only a short time before ovulation and play the important role in process of ovulation and luteinization. Thus a variety of clinical situations may be due to cytokine action in the gonads, and therapeutic manipulation of the immune system may affect reproductive function. Moreover the findings about the expression of some cytokines by oocytes and their presence in follicular fluid provide further evidence and substantiate the physiologic role for their in ovarian function, and may lead to clinical applications in programs of in vitro fertilization and in diagnosis and treatment of infertility in women, especially in cases attributed to ovarian dysfunction.