Effects of rat cytomegalovirus on the nervous system of the early rat embryo

The purpose of the study was to investigate the impact of rat cytomegalovirus (RCMV) infection on the development of the nervous system in rat embryos, and to evaluate the involvement of Wnt signaling pathway key molecules and the downstream gene neurogenin 1 (Ngn1) in RCMV infected neural stem cells (NSCs). Infection and control groups were established, each containing 20 pregnant Wistar rats. Rats in the infection group were inoculated with RCMV by intraperitoneal injection on the first day of pregnancy. Rat E20 embryos were taken to evaluate the teratogenic rate. NSCs were isolated from E13 embryos, and maintained in vitro. We found: 1) Poor fetal development was found in the infection group with low survival and high malformation rates. 2) The proliferation and differentiation of NSCs were affected. In the infection group, NSCs proliferated more slowly and had a lower neurosphere formation rate than the control. The differentiation ratio from NSCs to neurons and glial cells was significantly different from that of the control, showed by immunofluorescence staining. 3) Ngn1 mRNA expression and the nuclear β-catenin protein level were significantly lower than the control on day 2 when NSCs differentiated. 4) The Morris water maze test was performed on 4-week pups, and the infected rats were found worse in learning and memory ability. In a summary, RCMV infection caused abnormalities in the rat embryonic nervous system, significantly inhibited NSC proliferation and differentiation, and inhibited the expression of key molecules in the Wnt/β-catenin signaling pathway so as to affect NSCs differentiation. This may be an important mechanism by which RCMV causes embryonic nervous system abnormalities.     

Studies on glutathione S-alkyltransferase of the rat

1. A rat-liver enzyme catalysing the S-alkylation of glutathione by iodomethane and various other alkyl compounds has been identified and partially purified; its stability, specificity and response to inhibitors and activators and to changes in reaction pH have been studied. 2. The enzyme is distinct from glutathione S-aryltransferase, but both enzymes respond similarly to various inhibitors. 3. A similar enzyme has been found in the kidney and adrenal of rat and in the liver and kidney of numerous species. 4. The identity and the physiological role of the enzyme are discussed.     

Effect of normal rat serum injected into the uterus on fetal survival in the rat

We intended to use the rat model to study the effect of autoantibodies on implantation and fetal viability. However, we have since found an effect of normal rat serum on fetal resorption rate and fetal viability. The objective of this study was to determine the consistency of this effect. Wistar strain albino rats were used for injection of 150 μl normal rat serum into the lumen of uterine horn on days L₂–L₆. The other uterine horn, used as a control, was injected with 150 μl normal saline. Percent implantation, fetal resorption rate and fetal viability were determined following the intrauterine injection of normal rat serum as compared with normal saline. A significant increase in fetal resorption rate was observed following the injection of rat serum on days L₄ and L₅ (P = 0.003 and P = 0.001, respectively). A significant decrease in fetal viability was demonstrated following the injection of rat serum on day L₅ (P = 0.01). The rat can provide a suitable animal model for further studies.