Exploring the effects of second estrus synchronization and dietary flushing on the incidence of ovarian cysts in gilts by using exogenous gonadotropins / Explorando os efeitos da sincronização do segundo estro e flushing alimentar sobre a incidência de cistos ovarianos em marrãs utilizando gonadotrofinas exógenas

Estrus stimulation by exogenous gonadotropins (EG) in association with dietary flushing is an important tool for theimprovement of gilt reproductive performance. However, there is evidence associating both flushing and EG with a disturbance in the endocrine balance that could lead to increased ovarian cysts. The aim of this study was to evalu- ate whether flushing or EG might affect the ovulation rate and the incidence of ovarian cysts. Seventy-one gilts were randomly distributed into 2x2 factorial design with four treatments: flushing and hormone (wFwH); no flushing and hormone (nFwH); flushing without hormone (wFnH); and neither flushing nor hormone (nFnH). Gilts were slaughtered for macroscopic and histopathological ovary examination approximately five days after AI. The characterization of these cysts was performed by optical microscopy in the following: follicular cysts (FC), luteinizedcysts (LC) or cystic corpora lutea (CCL). The number of ovulations did not differ between treatments. There was no interaction between the factors in any analyzed variable. The frequency of gilts with CCL and LC was not affected by flushing and EG. No difference was found in the incidence of FC, with 12.5% and 5.88% in gilts from wFwH and nFwH treatments, respectively. There were no differences in the proportion of CCL between FC and LC (9.85 vs. 4.22 and 4.22%, respectively). In conclusion, the use of exogenous gonadotropins for second estrus synchronization in gilts, either alone or in association with dietary flushing, does not increase the incidence of ovarian cysts, nor does it decrease the ovulation rate.

A estimulação do estro por gonadotrofinas exógenas (GE) associada ao flushing alimentar é uma ferramenta importante na melhoria do desempenho reprodutivo de marrãs. Contudo, há evidência da associação do flushing com GE levando ao desequilíbrio no sistema endócrino que poderia levar ao aumento de cistos ovarianos. O objetivo deste estudo foi avaliar se o flushing ou GE pode afetar a taxa de ovulação e a incidência de cistos ovarianos. Setenta e uma marrãs foramdistribuídas aleatoriamente em arranjo fatorial 2x2 com quatro tratamentos: flushing e hormônio (cFcH); sem flushing e com hormônio (sFcH); com flushing e sem hormônio (cFsH) e sem flushing e hormônio (sFsH). Marrãs foram abatidas para exame macroscópico e histopatológico dos ovários, aproximadamente cinco dias após IA. A caracterização desses cistos foi realizada por microscopia óptica: cistos foliculares (CF), cistos luteinizados (CL) ou corpos lúteos císticos(CCL). O número de ovulações não diferiu entre os tratamentos. Não houve interação entre os fatores em qualquer variável analisada. A frequência de leitoas com CCL e CL não foi afetada pelo flushing e GE. Não houve diferença na incidência de CF, com 12,5% e 5,88 % em leitoas dos tratamentos cFcH e sFcH, respectivamente. Não foram obtidas diferenças na proporção de CCL entre CF e CL (9,85 vs. 4,22 e 4,22%, respectivamente). Em conclusão, a utilização de gonadotrofinas exógenas para sincronização do segundo estro de marrãs, isoladamente ou em associação com o flushing, não aumenta a incidência de cistos ovarianos e não diminui a taxa de ovulação.

Low-dose Radiation-induced Hormetic Effect in the Rat Ovarian Follicle / 체질인류학회지

Hormesis is the generally-favorable biological responses to low exposures to toxins and other stressors. Radiation hormesis is the theory that ionizing radiation is benign at low levels of exposure, and that doses at the level of natural background radiation can be beneficial. The purpose of this study is to reveal the hormetic effect of low-dose radiation of ionizing radiation on the ovarian follicles of 4-week old female mice. Mice were grouped into control group, 2 cGy irradiated group, 2 cGy and 2 Gy irradiated group (2 cGY pre-exposure group), and 2 Gy irradited group. Mice were sacrificed by cervical dislocation 24 hours after irradiation, removed ovaries, fixed in neutral formaldehyde solution for 24 hours, embedded with paraffin, stained with hematoxylin and eosin and TUNEL immunohistochemically, and observed light microscopically the atretic follicles and normal follicles in various follicular developmental stages. In this experiment, the ratrio of atretic follicles to entire follicles in an ovary increased significantly in 2 Gyirradiated group compared with 2 cGY pre-exposure group, and the ratio of normal follicles to the entire follicles in an ovary in all the developmental stages were increased significantly in the 2 cGY pre-exposure group compared with 2 Gy-irradiated group. These results mean that low-dose radiation pre-exposure can induce the hormetic effect in the developing ovarian follicle.

TNFalpha and TNFR2 Immunohistochemistry During Ovarian Follicular Development and Atresia in the Rat / 대한해부학회지

Tumor necrosis factor alpha (TNFalpha) is an intraovarian cytokine that may play a role in ovarian development and function. Identification of ovarian TNFalpha receptors provides support for establishing a role of TNFalpha in ovarian development and function. TNFalpha exerts its effects by binding to either TNF receptor 1 or 2 (TNFR1 or TNFR2). When TNFalpha binds with TNFR2, expression of survival genes is up-regulated, resulting in proliferation of granulosa cells. In the present study, the authors identified the changes in localization of TNFalpha and the expression of TNFR2 in granulosa cells during follicular atresia in rat ovaries. In healthy follicles, intense signals for TNFalpha and TNFR2 were found in the outer surface of the granulosa layer, where many proliferating cells and no apoptotic cells were observed. In atretic follicles, decreased expression of TNFalpha and TNFR2 was observed in the granulosa layer, where many apoptotic cells were seen. These findings suggested that TNFalpha acts as a survival factor in granulosa cells during follicular atresia in rat ovaries.

Distribution and Role of Ovarian Follicle Macrophage in Rat Ovarian Follicular Atresia / 대한산부인과학회지

OBJECTIVE: Ovarian follicular atresia is initiated from ovarian granulosa cell apoptosis and macrophages exert their effects directly and/or indirectly on follicular atresia by phagocytosis of apoptotic bodies and secretion of various cytokines. In spite of the abundant data on ovarian macrophages, the presence of these cells within the follicles (i.e., among granulosa cells) remains controversial and the elimination methods of apoptotic bodies of atretic follicles, and the time and methods of penetration of macrophages into the follicles are not known completely. The aim of the present study is to demonstrate the presence of macrophage within the ovary as related to follicular atresia and the process of elimination of apoptotic granulosa cells by light and electron microscopy. METHODS: Using rat ovaries, immunohistochemical studies with rat macrophage monoclonal antibody ED1 for macrophages, and light and transmission electron microscopic observations were performed. RESULTS: In the rat, follicular atresia was initiated by the granulosa cell apoptosis which occured randomly within the all granulosa layers. Macrophages were observed within normal follicles, in antrum, granulosa and theca cell layers of atretic follicels, in interstium and in corpus luteum. Ultrastructurally, apoptotic granulosa cells showed characteristics, pyknotic nucleus and apoptotic body formation. Apoptotic bodies were eliminated by intact neighboring granulosa cells and macrophages. Intact granulosa cells ingested apoptotic bodies transiently, soon after they fell into the apoptosis. Finally, apoptotic bodies and degenerating oocytes were phagocytosed by macrophages. Macrophages entered the ovarian follicle at the time of initiation of granulosa cell apoptosis, and migrated with the progression of apoptosis. By elimination of theca cells, macrophages contributed the completion of follicular atresia. CONCLUSION: This study demonstrates both intact neighboring granulosa cells and macrophages in the elimination of apoptotic bodies in atretic follicles of the rat ovary. Macrophages are present within normal follicles, in atretic follicles such as antrum, granulosa and theca cell layers and in corpus luteum but are in different appearances according to their location in ovary. A number of macrophages appearing in atretic follicles and in corpora lutea suggest a role for macrophages in follicular atresia and corpus luteum differentiation. The function of macrophage according to their location in follicular development should be further studied.

Follicular Atresia and Macrophages in the Porcine Ovary; Immunohistochemical and Transmission Electron Microscopic Study / 대한해부학회지

Apoptosis of granulosa cells leads follicular atresia and macrophages have an important role during the apoptotic process. However, the propagation of apoptosis within the follicle, the ways of elimination of apoptotic bodies and degenerated oocyte, and the completion of follicular atresia are still controversial and unidentified clearly. Using adult porcine (Yorkshire-breed) ovary, in this morphological study, transmission electron microscopic observation and immunohistochemical study with pig macrophage monoclonal antibody 4E9 were performed. In light microscopy, the follicular atresia initiated with apoptosis of granulosa cells, followed by degeneration of oocyte and apoptosis of theca interna cells. Apoptosis occured in random fashion among the granulosa cells and propagated multidirectionally, and finally to the granulosa cells surrounding zona pellucida of degenerating oocyte. Pyknosis of granulosa cells was the first sign of apoptosis. In immunohistochemistry, macrophages were found only in the granulosa layer at the stage of beginning of apoptosis. With progression of apoptosis, they were proliferated greatly in number enough to eliminate all the apoptotic bodies, and found within the follicular antrum. In advanced stage of atresia, macrophages surrounded the zona pellucida of degenerating oocyte, and found also in the theca interna. In transmission electron microscopy, phagocytic granulosa cells maintained characteristic gap junctions with neighboring granulosa cells and contained several apoptotic bodies and lipid droplets within their cytoplasm. Macrophages kept many apoptotic bodies, vacuoles and autophagosomes in their cytoplasm. Apoptotic granulosa cells were ingested by intact granulosa cells and macrophages initially, but lately, all the apoptotic granulosa cells and degenerated oocyte were eliminated by macrophages. Ovarian follicular atresia completed with phagocytosis of apoptotic theca interna cells by macrophages, and the remnants of the atretic follicle became ovarian stroma. It is well known that macrophages may play an important role during follicular atresia, such as elimination of apoptotic granulosa cells, theca interna cells and degenerated oocytes, but, the valid action mechanisms of macrophages on the initiation of granulosa cell apoptosis and on the completion of atresia through the secretion of paracrine factors and autocrine factors still unclear.

Morphological Study on the Radiation-induced Follicular Atresia and the Follicular Macrophage / 대한산부인과학회잡지

OBJECTIVE: It is well known that X-ray induces follicular atresia, but the exact mechanism of atresia is not still unveiled completely. In addition, the role of macrophage related with clean-up the dead granulosa cells and other functions within the ovarian follicle is emphasized recently. The aim of this study is to assess the radiation-induced morphological changes of ovarian follicles and follicular macrophages. METHODS: 8 Gy X-ray irradiated on the 3-week old rats (Sprague-Dawley strain), sacrificed at 6, 12, and 24 hours after irradiation, and performed morphological studies with light and transmission electron microscopy, TUNEL, and macrophage immunohistochemistry. RESULTS: Follicular atresia increased significantly (p<0.01) at 6 hours after X-irradiation, and it was decreased significantly (p<0.01) at 12 and 24 hours after irradiation. X-ray induced chromatin condensation in the nucleus and nuclear fragmentation of granulosa cells, which were the typical features of apoptosis. Apoptotic granulosa cells were phagocytosed by the neighboring normal granulosa cells and the macrophages. During atresia of follicles, radioresistant granulosa cells were found in some follicles, which showed similar features morphologically with the granulosa cells of normal follicles. Macrophages were found both within the antrum and at the follicular granulosa layer. CONCLUSION: X-radiation induced follicular atresia by means of granulosa cell apoptosis, and radioresistant granulosa cells which have similar features morphologically with the granulosa cells of normal follicles were observed in some follicles. And the macrophages which phagocytose the apoptotic granulosa cells were located within the follicular antrum and at the follicular granulosa layer.

Apoptosis and Bcl-2/Bax expression in the early follicles of reproductive women / 中国病理生理杂志

AIM: To investigate the apoptosis and Bcl-2/Bax expression in the early follicles of women at reproductive age. METHODS: 12 ovarian specimens were collected from reproductive women (aged 23-38 years) undergoing gynaecological operation. Histopathological examination of these specimens was performed to confirm its' morphological normalities. Using TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling) assay and immunohistochemistry method, cell apoptosis and Bcl-2/Bax expression were examined in the early follicles including mainly primordial, intermediary and primary follicles. RESULTS: 18.75% of the oocytes were found TUNEL positive in the early follicles, but no granulosa cells in these follicles were found TUNEL positive. Bax expression was detected in 76.07% of the oocytes in the early follicles, but Bcl-2 expression was negative in these oocytes. In addition, Bcl-2/Bax expression were not present in the granulosa cells in early follicles. CONCLUSION: The oocyte apoptosis occurs in the early follicles of reproductive woman, and pro-apoptotic protein Bax may play a role in regulating this process. It suggests that Bax mediated oocyte apoptosis may be the molecular mechanism of the early follicle atresia in the ovaries of reproductive woman. [