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Theca cells (TCs) are essential to folliculogenesis by contributing to steroidogenesis. However, the in vitro growth (IVG) of oocytes co-cultured with TCs has not yet been examined. In the present study, we investigated the feasibility of the IVG of bovine oocyte-cumulus-granulosa cell complexes (OCGCs) co-cultured with TCs and the developmental competence of co-cultured oocytes. OCGCs and TCs were co-cultured without steroid hormone addition for 12 days. Steroidogenesis, the viability of OCGCs, and TC numbers during co-culture were assessed every 4 days. After IVG, oocytes were matured and the nuclear status was evaluated. Some oocytes were inseminated and cultured to examine blastocyst development. During the co-culture, androstenedione production by TCs was only observed during the first 4 days (1.1 ng/well) while estradiol-17β was continuously produced, peaking during the second 4 days (0.5 ng/well). The number of TCs decreased to ∼60% of the seeding number (4.0 × 104 cells/well) during the first 4 days, and was maintained thereafter. The majority of co-cultured OCGCs (82.7%) survived after 12-day IVG. Only a few OCGCs (6.2%) survived in the OCGC culture without TCs (p < 0.01); however, the addition of androstenedione to the culture medium markedly improved survivability to 80.1%, which was similar to that in the co-culture with TCs. In the subsequent development of oocytes derived from the co-culture, 58.3% reached metaphase II stage, 58.7% cleaved, and 17.3% developed to blastocysts, which were similar values to those of oocytes cultured with the addition of androstenedione. In conclusion, TC-produced androgen contributes to OCGC growth and the acquisition of subsequent embryonic developmental competence. • Theca cells can produce androstenedione and support oocyte development in vitro. • However, theca cells showed quick spontaneous luteinization. [ABSTRACT FROM AUTHOR]

• Proposed a dynamic dissimilarity index to improve the adaptability to different features and the dynamicity of the model. • Proposed a dynamic integrated SFA, which solves the monitoring of multi-dimensional quality variables. • A transfer entropy method with time lag is proposed to optimize the causality graph for root cause diagnosis of faults. In this paper, the monitoring method based on slow feature analysis and the root cause diagnosis based on transfer entropy are proposed. Different from the traditional methods, this paper performing online modelling to improve the adaptability to different data features and the dynamics of the model. A Dynamic Dissimilarity Index (DDI) is proposed to construct a dynamic online sub-block partitioning model. For process monitoring of multidimensional quality variables, a weighted fusion method is proposed to integrate multiple models so that the monitoring conclusions include the quality changes of the process. The fault variables are identified for quality-related faults, and the traditional method is improved by proposing a transfer entropy method with time lag parameters added to optimize the fault causality diagram. Finally, the study of real chemical processes shows that the proposed method gives more accurate and richer monitoring conclusions and can find the root cause more quickly and efficiently. [ABSTRACT FROM AUTHOR]

Bone morphogenetic protein-4 (BMP-4) and FSH play important regulatory roles in follicular growth and steroidogenesis in vivo . The purpose of this study was to investigate the effects of BMP-4 and FSH on in vitro growth (IVG) and steroidogenesis of bovine oocyte-cumulus-granulosa complexes (OCGCs). We cultured OCGCs collected from early antral follicles (0.5–1 mm) in medium without BMP-4 and FSH for 4 days and investigated the appearance of OCGCs and their steroidogenesis. During the first 4 days of IVG, morphologically normal OCGCs produced more estradiol-17β (E 2 ), but less progesterone (P 4 ). Morphologically normal OCGCs were subjected to an additional culture in medium supplemented with BMP-4 (0, 10, and 50 ng/mL) and FSH (0 and 0.5 ng/mL) until day 12. We examined the viability and steroidogenesis of OCGCs after 8 and 12 days of culture. Oocyte growth, characteristics of granulosa cells, and the maturational competence of oocytes were also investigated. On day 8, the viability of OCGCs cultured without FSH was higher in the 10 ng/mL BMP-4 group than in the 50 ng/mL BMP-4 group (P < 0.05). No significant difference was observed in the viability of groups cultured with FSH, regardless of the addition of BMP-4, and FSH improved the viability of 50 ng/mL BMP-4 group similar to 10 ng/mL BMP-4 group. The total number of granulosa cells was larger in 10 ng/mL BMP-4 group cultured with FSH than in 50 ng/mL BMP-4 group cultured with FSH on day 8 (P < 0.05). E 2 production decreased from days 8–12, and P 4 production increased throughout IVG culture, regardless of the addition of BMP-4 and FSH (P < 0.05). No significant differences in E 2 production were observed between groups from days 4–8, regardless of whether BMP-4 was added without FSH; however, E 2 production in the group cultured with 50 ng/mL BMP-4 was suppressed by FSH. BMP-4 suppressed E 2 production from days 8–12, regardless of whether FSH was added. The group cultured with 10 ng/mL BMP-4 without FSH showed the lowest P 4 production among all groups for all culture periods. OCGCs that produced mature oocytes tended to secrete more E 2 and less P 4 than OCGCs that produced immature oocytes. In conclusion, until day 8 of the IVG culture, P 4 production by OCGCs was suppressed by the addition of 10 ng/mL BMP-4 in the absence of FSH, without inhibiting E 2 production. These conditions appear to mimic growing follicles until day 8 and mimic degenerating follicles from days 8–12 of culture. [ABSTRACT FROM AUTHOR]