Overexpression of human selenoprotein M differentially regulates the concentrations of antioxidants and H2O2, the activity of antioxidant enzymes, and the composition of white blood cells in a transgenic rat.

Selenoprotein is associated with a variety of serious diseases, including infectious diseases, neurodegenerative disorders, cancer and cardiovascular disease. The aim of this study was to produce a new transgenic (Tg) rat expressing human selenoprotein M (SelM) in order to examine the protective function of the antioxidant status in vivo. To achieve this, a new lineage of Tg rats was produced by the microinjection of pCMV/GFP-hSelM constructs into a fertilized rat egg. Several conclusions can be drawn based on the results of the present study. The human SelM gene was successfully expressed at both the transcription and protein levels in the CMV/GFP-hSelM Tg rats. This Tg rat showed a different enzyme activity for the antioxidant protein in the various tissues examined. In response to the 2,2'-azobiz(2-amidinopropane) dihydrochloride (AAPH) injection, the Tg rats showed a lower level of antioxidant and H2O2 concentration as the activity of the antioxidant enzyme was maintained at a higher level in the Tg rats than in the non-Tg rats. Also, the neutrophil-to-lymphocyte ratio was significantly increased in this Tg rat, even though the level of corticosterone remained unchanged in both genotypes. Thus, the results of this study demonstrated that the CMV/GFP-hSelM Tg rat can serve as an animal model for the maintenance of a high level of antioxidant status and can be used to study the biological function of selenoprotein in infectious diseases, cardiovascular disease and cancer.

The effects of long-duration, low-temperature ground transportation on physiological and biochemical indicators of stress in mice.

Transportation can cause stress to laboratory animals and alter physiological characteristics that may confound experimental results. The authors investigated stress-related effects of 3-4 h of transportation by truck in two strains of mice (C57BL/6, which are known to be aggressive, and ICR, which are less aggressive). Transported mice had sufficient space and access to water, though temperature in the truck was lower than what is usually recommended. Transportation affected the following parameters in both strains of mice: (i) serum corticosterone concentrations, (ii) expression of the chaperone proteins Hsp70 and Grp78 in various tissues and (iii) concentrations of serological enzymes that are associated with liver disease. These parameters also differed substantially between the two strains of mice.

Differential regulation of the biosynthesis of glucose transporters by the PI3-K and MAPK pathways of insulin signaling by treatment with novel compounds from Liriope platyphylla.

The insulin signaling pathway, involving protein kinase B (PKB) and mitogen-activated protein kinase (MAPK), mediates the biological response to insulin and several growth factors and cytokines. To investigate the correlation between glucose transporter (Glut) biosynthesis and the insulin signaling pathway activated by novel compounds of Liriope platyphylla (LP9M80-H), alterations in Glut and key protein expression in the insulin signaling pathway were analyzed in the liver and brain of ICR mice treated with LP9M80-H. An in vitro assay showed that the highest level of insulin concentration was observed in the LP9M80-H-treated group, followed by the LP-H, LP-M, LP-E, and LP9M80-C-treated groups. Therefore, LP9M80-H was selected for use in studying the detailed mechanism of the insulin signaling pathway in animal systems. In an in vivo experiment, LP9M80-H induced a significant increase in glucose levels and a decrease of insulin concentration in the blood of mice, while their body weight remained constant over 5 days. The expression level of Glut-3 was down-regulated in the liver, or maintained at the same level in the brain of LP9MH80-H-treated mice. These changes corresponded to the phosphorylation of the p38 protein rather than to ERK and JNK in the MAPK signaling pathway. In addition, the expression level of Glut-1 increased significantly after LP9MH80-H treatment of both insulin target tissues in mice. Western blot analysis showed that Akt in the PI3-K pathway mainly participated in Glut-1 biosynthesis. Thus, these results suggest the possibility that the LP9M80-H-induced regulation of Glut-1 and Glut-3 biosynthesis may be mediated by the Akt and p38 MAPK signaling of the insulin signaling pathway in the liver and brain of mice.

Overexpression of Insulin Degrading Enzyme could Greatly Contribute to Insulin Down-regulation Induced by Short-Term Swimming Exercise.

Exercise training is highly correlated with the reduced glucose-stimulated insulin secretion (GSIS), although it enhanced insulin sensitivity, glucose uptake and glucose transporter expression to reduce severity of diabetic symptoms. This study investigated the impact of short-term swimming exercise on insulin regulation in the Goto-Kakizaki (GK) rat as a non-obese model of non-insulin-dependent diabetes mellitus. Wistar (W/S) and GK rats were trained 2 hours daily with the swimming exercise for 4 weeks, and then the changes in the metabolism of insulin and glucose were assessed. Body weight was markedly decreased in the exercised GK rats compare to their non-exercised counterpart, while W/S rats did not show any exercise-related changes. Glucose concentration was not changed by exercise, although impaired glucose tolerance was improved in GK rats 120 min after glucose injection. However, insulin concentration was decreased by swimming exercise as in the decrease of GSIS after running exercise. To identify the other cause for exercise-induced insulin down-regulation, the changes in the levels of key factors involved in insulin production (C-peptide) and clearance (insulin-degrading enzyme; IDE) were measured in W/S and GK rats. The C-peptide level was maintained while IDE expression increased markedly. Therefore, these results showed that insulin down-regulation induced by short-term swimming exercise likely attributes to enhanced insulin clearance via IDE over-expression than by altered insulin production.

Alpha-tocopheryl succinate sensitizes human colon cancer cells to exisulind-induced apoptosis.

Sulindac sulfone (also known as exisulind) and its chemical derivatives are promising anticancer agents capable of inducing apoptosis in a variety of malignant cell types with minimal toxicity to normal cells. Here, we tested the ability of alpha-tocopheryl succinate (TOS), another promising anticancer agent, to sensitize colon cancer cells to exisulind-induced apoptosis. We found that sub-apoptotic doses of TOS greatly enhanced exisulind-induced growth suppression and apoptosis in the HCT116, LoVo and SNU-C4 human colon cancer cell lines. Our results revealed that this was accounted for primarily by an augmented cleavage of poly(ADP-ribose) polymerase (PARP) and enhanced activation of caspase-8, -9 and -3. Pretreatment with z-VAD-FMK (a pan-caspase inhibitor), z-IETD-FMK (a caspase-8 inhibitor) or z-LEHD-FMK (a caspase-9 inhibitor) blocked TOS and exisulind cotreatment-induced PARP cleavage and apoptosis. Furthermore, TOS/exisulind cotreatment induced JNK phosphorylation, while pretreatment with SP600151 (a JNK inhibitor) partially blocked cotreatment-induced caspase-dependent PARP cleavage and apoptosis. Taken together, these findings indicate that TOS sensitizes human colon cancer cells to exisulind-induced apoptosis. Apoptotic synergy induced by exisulind plus TOS seems likely to be mediated through a mechanism involving activation of caspases and JNK.

Microbiological monitoring of guinea pigs reared conventionally at two breeding facilities in Korea.

In this study, microbiological monitoring of guinea pigs reared conventionally in two facilities was performed twice in 2004, with a three-month-interval between surveys. This study was based on the recommendations of the FELASA Working Group, with some modifications. In serological tests in the first survey, some animals from facility A showed positive results for Encephalitozoon cuniculi, Sendai virus, pneumonia virus of mice (PVM), and Reovirus-3 (Reo-3); facility B showed a positive result only for E. cuniculi. The results of the second survey were similar to the first, except for the presence of Sendai virus; all animals from the two facilities were Sendai virus-negative in the second experiment. No pathogenic bacteria were cultured in the organs of any of the animals in the first survey. However, in the second survey, Bordetella bronchiseptica was cultured from the lung tissue of two 10-week-old animals from facility A. Chlamydial infection was examined by the Macchiavello method, but no animal showed positive results. Tests using fecal flotation or the KOH wet mount method showed no infection of endoparasites, protozoa, ectoparasites, or dermatophytes in any animal in both surveys. However, in the histopathological examination, an infection of protozoa-like organisms was observed in the cecum of some animals from facility A. The present study revealed that microbiological contamination was present in guinea pigs reared conventionally in two facilities in Korea, suggesting that there is a need to improve environmental conditions in order to eradicate microbial contamination.

Tumor necrosis factor-alpha gene promoter polymorphism in coal workers' pneumoconiosis.

Tumor necrosis factor-alpha (TNF-alpha) is believed to play a central role in the pathogenesis of pneumoconiosis. TNF2, a polymorphism in the TNF-a gene promoter, has been associated with an increase in TNF-alpha production and airway inflammation. To investigate the frequency of TNF2 in patients who have coal workers' pneumoconiosis (CWP) and to determine whether it is associated with development of a large opacity in CWP, we investigated the expression ofthe TNF2 allele in 80 patients who had CWP and in 54 healthy controls using restriction fragment length polymorphism (RFLP). Compared to controls (10.2%), the frequency of the TNF2 allele was greater in the CWP patients (20.6%). Furthermore, the TNF2 allele was very common in patients who had a large opacity (28.2%) in comparison with 13.4% in those with simpleCWP. From these data, we suggest that the TNF2 allele is associated with the development of a large opacity in CWP.

Role of dietary fat type in the development of adiposity from dietary obesity-susceptible Sprague-Dawley rats.

The present study was designed to define how dietary fat type regulates body adiposity in dietary obesity-susceptible (DOS) Sprague-Dawley (SD) rats. Eighty-three SD rats received a purified diet containing 50 g maize oil (MO)/kg for 3 weeks and then thirty-nine of the rats, designated as the DOS rats, were allotted to diets containing 160 g MO (DOS-MO), beef tallow (DOS-BT) or fish oil (DOS-FO)/kg for 9 weeks. As a result of the experiment, the DOS-FO rats had significantly (P<0.05) reduced weight gain and abdominal and epididymal fat-pad mass than the DOS-MO and DOS-BT rats. Serum leptin level was also significantly (P<0.05) lower in the DOS-FO rats; however, hypothalamic leptin receptor (a and b) mRNA and neuropeptide Y expressions were not altered by dietary fat sources. A lower acetyl-CoA carboxylase mRNA expression in the liver was observed in the DOS-FO group, whereas hepatic peroxisome proliferator-activated receptor-gamma mRNA and protein expressions were markedly elevated in the DOS-FO group compared with those in the other groups. We did not observe differences in acetyl-CoA carboxylase and peroxisome proliferator-activated receptor-gamma expressions in epididymal fat of the DOS rats consuming MO, BT or FO. It is concluded from our present observations that dietary fat type, especially that rich in FO, plays a potential role in down-regulation of adiposity by altering hepatic lipogenic genes, rather than feeding behaviour, in the DOS-SD rats.