Impact of adrenocorticotropin hormone administration on the endocrinology, estrus onset, and ovarian function of weaned sows.

Chronic stress affects the reproductive health of mammals; however, the impact of adrenocorticotropin hormone (ACTH) level elevation during chronic stress on the reproduction of weaned sows remains unclear. In this study, nine weaned sows with the same parturition date were randomly divided into control group (n = 4) and ACTH group (n = 5). Each group received intravenous administration of ACTH three times daily for 7 days. Blood samples were collected every 3 h after injection. A radioimmunoassay was used to measure the concentrations of cortisol, luteinizing hormone (LH), follicle-stimulating hormone (FSH), progesterone (P4) and estradiol-17ß (E2) in the blood. Estrus was determined according to changes in the vulva and the boar contact test. The mRNA expressions of glucocorticoid receptor, FSH receptor, LH receptor (LHR) in the corpus luteum (CL) were detected by qRT-PCR. The results showed that ACTH administration substantially delayed the initiation of estrus and the pre-ovulatory LH peak. The sows of control group ovulated within 10 days and the ovulation rate was 100%, while it was 60% in the ACTH group. Two sows of ACTH group showed pseudo-estrus. The E2 concentrations significantly decreased in the ACTH group at 36 h, 42 h and 66 h of the experimental period. The P4 concentrations in the ACTH group significantly decreased at 132, 138, and 147 h of the experimental period. ACTH significantly reduced the LHR mRNA expression in CLs. In conclusion, long-term repeated ACTH administration affects the endocrinology, estrus onset, and ovarian function of weaned sows.

Isolation, Culture and Identification of Porcine Skeletal Muscle Satellite Cells.

The objective of this study was to establish the optimum protocol for the isolation and culture of porcine muscle satellite cells. Mononuclear muscle satellite cells are a kind of adult stem cell, which is located between the basal lamina and sarcolemma of muscle fibers and is the primary source of myogenic precursor cells in postnatal muscle. Muscle satellite cells are a useful model to investigate the mechanisms of muscle growth and development. Although the isolation and culture protocols of muscle satellite cells in some species (e.g. mouse) have been established successfully, the culture system for porcine muscle satellite cells is very limited. In this study, we optimized the isolation procedure of porcine muscle satellite cells and elaborated the isolation and culture process in detail. Furthermore, we characterized the porcine muscle satellite cells using the immunofluorecence. Our study provides a reference for the isolation of porcine muscle satellite cells and will be useful for studying the molecular mechanisms in these cells.

Expression of PUMA in Follicular Granulosa Cells Regulated by FoxO1 Activation During Oxidative Stress.

Many studies have demonstrated that oxidative stress-induced apoptosis is a main cause of follicular atresia. Reactive oxygen species (ROS)-induced granulosa cell (GC) apoptosis is regulated by a variety of signaling pathways involving numerous genes and transcription factors. In this study, we found expression of the p53-upregulated modulator of apoptosis (PUMA), a BH3-only Bcl-2 subfamily protein, in ovarian GCs during oxidative stress. By overexpression and knockdown of Forkhead box O1 (FoxO1), we found that FoxO1 regulates PUMA at the protein level. Moreover, as c-Jun N-terminal kinase (JNK) has been shown to activate FoxO1 by promoting its nuclear import, we used a JNK inhibitor to reduce FoxO1 activation and detected decreased PUMA messenger RNA expression and protein levels during oxidative stress. In addition, in vivo oxidative stress-induced upregulation of PUMA was found following injection of 3 nitropropionic acid in mice. In conclusion, oxidative stress increases PUMA expression regulated by FoxO1 in follicular GCs.