Isolation, proliferation, and induction of Bama mini-pig spermatogonial stem cells in vitro.

Spermatogonial stem cells (SSCs), the unique seed cells of testes, can undergo meiosis and form spermatozoa, thus transmitting genetic information to offspring. Research concerning these cells explores the mechanism underlying spermatogenesis, making possible the induction of their differentiation into spermatozoa in vitro. SSCs have therefore attracted much interest among scientists. Although the proliferation of such cells in vitro has been demonstrated, we are unaware of any long-term laboratory culture of porcine SSCs. The objective of this study was to isolate, characterize, culture, and induce the differentiation of Bama mini-pig SSCs. SSCs were isolated using differential plating and cultured for over 100 days on an STO feeder cell layer without serum. Cell clusters appeared after three passages and continuously formed during subsequent cultivation. Staining showed that these clusters were positive for UCHL1 and CDH1, could be bound by Dolichos biflorus agglutinin, and that some cells expressed OCT4. Ultrastructure observations revealed SSCs in testis tissue to be round in shape, while those cultured in vitro were flat and bound together. Our attempts at inducing differentiation showed that SSCs cultured in vitro could undergo meiosis. In this study, we describe an effective culture system for Bama mini-pig SSCs capable of producing enough cells to establish a platform for further SSC research, such as genetic manipulation or exploration of the mechanism underlying spermatogenesis.

Production of hGFAP-DsRed transgenic Guangxi Bama mini-pigs via somatic cell nuclear transfer.

The mini-pig is a useful animal model for human biomedical research due to its physiological similarity to humans and the ease of handling. In order to optimize the efficiency of production of transgenic Bama mini-pigs through somatic cell nuclear transfer (SCNT), we examined the effects of contact inhibition, roscovitine treatment, and serum starvation on the cell cycle synchronization and transgenic cloned embryo development in vivo and in vitro after nuclear transfer. The analysis showed that the rates of G0/G1 stage cells in the contact inhibition (92.11%) and roscovitine treatment groups (89.59%) were significantly higher than in serum starvation group (80.82%). A higher rate of apoptosis was seen in the serum starvation group (14.13%) compared to the contact inhibition and roscovitine treatment groups (6.71 and 2.46% respectively, P < 0.05). There was a significant decrease in blastocyst yield in the serum starvation group (14.19%) compared to the roscovitine treatment and contact inhibition groups (21.31 and 20.32% respectively, P < 0.05). A total of 1070 transgenic cloned embryos derived from the three treatment groups were transferred to surrogate sows; one pregnancy was established and three embryos from the roscovitine treatment group successfully completed gestation. These results indicate that the roscovitine treatment was more effective at synchronizing transgenic kidney cells in Bama mini-pigs and allowed reconstructed embryos to develop to full term.

Gynecologic cancers associated with Lynch syndrome/HNPCC.

Lynch syndrome/hereditary nonpolyposis colorectal cancer (HNPCC) is an autosomal dominant inherited cancer susceptibility syndrome caused by a germline mutation in one of the deoxyribonucleic acid (DNA) mismatch repair genes. It is associated with early onset of cancer (age younger than 50 years) and the development of multiple cancer types, particularly colon and endometrial cancer. Women with Lynch syndrome have a 40-60% risk of endometrial cancer, which equals or exceeds their risk of colorectal cancer. In addition, they have a 12% risk of ovarian cancer. Despite limited information on the efficacy of surveillance in reducing endometrial and ovarian cancer risk in women with Lynch syndrome, the current gynecologic cancer screening guidelines include annual endometrial sampling and transvaginal ultrasonography beginning at age 30-35 years. In addition, risk-reducing surgery consisting of prophylactic hysterectomy and bilateral salpingooophorectomy should be offered to women aged 35 years or older who do not wish to preserve their fertility.