P53 expression between 13-27 weeks old human male fetus gonads

Effects of quercetin on apoptosis, NF-κB and NOS gene expression in renal ischemia/reperfusion injury

The aim of this study was to investigate the effects of quercetin on nitric oxide synthase (NOS), nuclear factor-κB (NF-κB) and apoptosis in renal ischemia/reperfusion (I/R) injury in rats. A total of 42 Sprague-Dawley rats were divided into three groups. The control, I/R and I/R+quercetin (I/R+Q) groups were treated with quercetin (50 mg/kg intraperitoneal) 1 h prior to the induction of ischemia. Tissue malondialdehyde (MDA) and glutathione (GSH) levels were determined by high-performance liquid chromatography (HPLC). p53, endothelial NOS (eNOS) and NF-κB expression were assessed immunohistochemically, and apoptosis assesment was performed using terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) assay. The mRNA levels of inducible NOS (iNOS) in renal tissue were determined by real-time polymerase chain reaction (RT-PCR). MDA levels were significantly decreased in the quercetin group compared to the I/R group. However, GSH levels were significantly increased with quercetin treatment in the I/R group. Histological results, the number of apoptotic and p53-positive cells, NF-κB and eNOS expression levels were significantly decreased in the quercetin treatment group compared to the I/R group. iNOS gene expression increased in the I/R group, but no significant difference was found between the I/R and quercetin treatment groups. Therefore, quercetin not only has antioxidant and anti-apoptotic activities, but also has an inhibitory effect on eNOS and NF-κB for renal tissue protection during I/R injury in rats. Therefore, quercetin may be a promising renoprotective therapeutic agent.

Cell cycle control of germ cell differentiation

The germ cell lineage is our lifelong reservoir of reproductive stem cells and our mechanism for transmitting genes to future generations. These highly specialised cells are specified early during development and then migrate to the embryonic gonads where sex differentiation occurs. Germ cell sex differentiation is directed by the somatic gonadal environment and is characterised by two distinct cell cycle states that are maintained until after birth. In the mouse, XY germ cells in a testis cease mitotic proliferation and enter G(1)/G(0) arrest from 12.5 dpc, while XX germ cells in an ovary enter prophase I of meiosis from 13.5 dpc. This chapter discusses the factors known to control proliferation and survival of germ cells during their journey of specification to sex differentiation during development.