The cigarette smoke constituent benzo[a]pyrene disrupts metabolic enzyme, and apoptosis pathway member gene expression in ovarian follicles.

Benzo[a]pyrene (B[a]P) is a prototypical polycyclic aromatic hydrocarbon (PAH) present in cigarette smoke. We previously showed that B[a]P adversely affects follicular development and survival. The objective of this study was to identify the key molecular pathways underlying B[a]P-induced abnormal follicular development. Isolated follicles (100-130 µm) from ovaries of F1 hybrid (C57BL/6j×CBA/Ca) mice were cultured for 8 (preantral/antral follicles) and 12 (preovulatory follicles) days in increasing concentrations of B[a]P (0 ng/mL [control] to 45 ng/mL). Expression of aryl hydrocarbon receptor (AhR), aryl hydroxylase steroidogenic enzyme, cell-cycle, and apoptotic genes were quantified. B[a]P exposure significantly (P<0.05) increased mRNA expression of Cyp1a1 in preantral/antral follicles and Cyp1b1, Bax and Hsp90ab1 in preovulatory follicles. No significant effect on mRNA expression of StAR, Cyp11a1, aromatase, Cdk4, Cdk2, Ccnd2, cIAP2, and survivin was observed. In conclusion, this study suggests that B[a]P exposure significantly affects the phase I enzymes and cell death genes during preantral/antral and preovulatory growth, and thus highlight the AhR signaling and apoptotis pathways in delayed follicle growth and decreased viability.

In vitro oocyte maturation: current status.

Due to its numerous clinical applications, in vitro maturation (IVM) has emerged as a significant topic in the field of assisted reproduction. IVM of germinal vesicle breakdown/metaphase I and germinal vesicle stage oocytes collected from in vitro fertilization (IVF) superovulation cycles are commonly applied with unsatisfactory results. The biological aspect of this so-called rescue in vitro oocyte maturation greatly differs from the actual IVM practice. In the latter, immature oocytes are obtained from small antral follicles of unprimed or minimally stimulated cycles aiming to avoid ovarian hyperstimulation syndrome in high-risk patients or simply as an alternative to conventional IVF in normo-ovulatory patients. Over the past decade, cases reports regarding IVM have been sporadically reported, with ~25 peer-reviewed articles currently available. These studies present variable outcomes and deal with clinical approaches about selecting the most appropriate patient population that could benefit from IVM technology. Although some of the studies are encouraging, the vast majority includes small sample sizes, thus making the data rather inconclusive. As such there is a certain reserve in the IVF community to embark on treatment cycles for IVM in routine use. Laboratory parameters play an important role in the success of IVM, and research for optimal culture conditions is warranted. Existing data from newborns assure us that IVM may be a safe procedure provided in assisted reproductive technology. When optimized, it will serve, not only for infertile patients, but also as a more patient-friendly alternative than standard controlled ovarian stimulation to obtain oocytes for donation or preservation of fecundity.

Cigarette smoke condensate exposure delays follicular development and function in a stage-dependent manner.

OBJECTIVE: To determine the effects of cigarette smoke condensate (CSC) on follicular development and function from the early preantral stage through ovulation. DESIGN: Prospective laboratory study. SETTING: Academic research environment. ANIMAL(S): Female F1 hybrid (C57BL/6j×CBA/Ca) mice. INTERVENTION(S): Mouse early preantral follicles (100-130 µm) were exposed to increasing concentrations of CSC (0 µg/mL [control] to 130 µg/mL) during in vitro growth and ovulation. MAIN OUTCOME MEASURE(S): Follicular development, follicle survival, gonadal steroid output, expansion of the cumulus-oocyte complex, oocyte growth, and maturation. RESULT(S): Cigarette smoke condensate exposure significantly inhibited follicular development in the preantral and antral stage and decreased follicle survival at 90 µg CSC/mL and higher. Estradiol output was significantly lower in CSC-exposed (90 and 130 µg/mL) follicles. Before ovulation, CSC significantly increased P output, which decreased thereafter. Cigarette smoke condensate exposure reduced cumulus-oocyte complex expansion and subsequently reduced the number of polar body oocytes. CONCLUSION(S): Cigarette smoke condensate exposure inhibits follicle development and leads to premature luteinization of the preovulatory follicle, with decreased oocyte maturation in a mouse isolated follicle culture system that mimics murine folliculogenesis in vivo.

Effect of in utero and lactational nicotine exposure on the male reproductive tract in peripubertal and adult rats.

The objective of this study was to determine the effect of in utero and lactational exposure to nicotine on the male reproductive tract. Dams were randomly assigned to receive saline or nicotine bitartrate (1mg/kg-d s.c.) daily for two weeks prior to mating until weaning (postnatal day 21). Male offspring were sacrificed at 7 (peri-pubertal) and 26 (adult) weeks of age. Nicotine-exposure resulted in retention of spermatids after stage VIII, tubular vacuolation, degeneration of pachytene and round spermatids at stage VII in the testes; and lymphocyte infiltration, germ cell exfoliation, and hypospermia in epididymides, at 7 weeks of age. Nicotine-exposure had no effect on testis or epididymal morphology, daily sperm production, epididymal sperm reserve, sperm viability at 26 weeks of age, and circulating testosterone levels at either age examined. We conclude that maternal nicotine-exposure during pregnancy and lactation can induce transient structural changes in the testis and epididymis of male offspring.

Morphological and ultrastructural evaluation of cultured frozen-thawed human fetal ovarian tissue.

OBJECTIVE: To investigate a defined culture condition for the culture of frozen-thawed human ovarian tissue. DESIGN: Prospective laboratory study. SETTING: Reproductive biology laboratories in university hospitals. PATIENT(S): Fetal ovarian tissue from elective termination of pregnancy. INTERVENTION(S): Culture of frozen-thawed fetal ovarian tissue for up to 63 days. MAIN OUTCOME MEASURE(S): Morphology, morphometry, and survival of follicles in relation to culture times. RESULT(S): The proportion of primordial, early primary, and primary follicles in frozen-thawed (day 0) ovarian tissue was 77.5%, 21.7%, and 0.8%, respectively. Pronounced degeneration was found in all cell types, and < or =36% of the follicles had signs of atresia at days 7-14, but this figure improved with culture time to <20% of the total follicular population. After 7-14 and 21-35 days of culture, the relative proportion of the follicles in the different classes remained nearly stable. Morphometric examination of healthy follicles showed a significant increase in both follicle and oocyte diameter compared with control. A few follicles had developed to the early secondary stage. Ultrastructural analysis demonstrated well-preserved morphological integrity of healthy primordial and early primary follicles. Immunohistochemical localization of proliferating cell nuclear antigen was positive in proliferating follicular cells at days 7-14 and 21-35 of culture. CONCLUSION(S): The present culture condition leads to good survival and progressive follicular growth and differentiation that is comparable to the physiological pattern of early folliculogenesis.