Overaccumulation of Fat Caused Rapid Reproductive Senescence but not Loss of Ovarian Reserve in ob/ob Mice

Ovarian reserve and fertility are reduced by aging and a poor energy balance. To date, the relationships of high energy accumulation and aging with the ovarian reserve have not been elucidated. Here, the effects of obesity on the aging ovarian reserve were evaluated in a leptin-deficient (ob/ob) mouse model. Abnormal estrous cyclicity appeared as early as 6 weeks and worsened with aging. The blood level patterns of 17β-estradiol (E2), testosterone (T), and progesterone (P4) with aging were similar between lean and ob/ob mice. The blood level of E2 but not P4 or T was similar at 24 weeks. Many more atretic follicles but fewer corpora lutea were observed in ob/ob mice than in lean mice within all age groups. Anti-Müllerian hormone (Amh) mRNA levels were similar between genotypes. Dazl, Stra8, and ZP3 mRNAs were highly expressed in ob/ob mice after 12 weeks. Sohlh1 and Ybx2 mRNAs were highly expressed at 24 weeks in ob/ob compared with lean mice. In addition, SOHLH1-positive primordial follicle counts were significantly increased in ob/ob mice at 24 weeks. The proportions of AMH-positive secondary and small antral follicles were similar between genotypes. Together, these results show that the ovarian reserve lasts longer in ob/ob mice than in lean mice, suggesting that the loss of normal physiological or physical status causes decreased fertility at a young age in ob/ob mice and that an increase in adipocytes without leptin, as in ob/ob mice, can improve the ovarian reserve. Such knowledge can be applied to understanding reproductive dysfunction.

Induction of apoptosis of SW480 human colon cancer cells by (-)-epicatechin isolated from Bulnesia sarmienti

BACKGROUND/AIM

(-)-Epicatechin is a major constituent of Bulnesia sarmienti, which is known to possess anticancer properties. Here we report that (-)-epicatechin isolated from B. Sarmienti inhibited growth and induced apoptosis of SW480 human colon cancer cells.

MATERIALS AND METHODS

Cells were treated with different concentrations (0, 25, 50, and 100 μmol/ml) of (-)-epicatechin. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, 40,6-diamidine-20-phenylindole dihydrochloride (DAPI) staining, colony-forming assay, DNA fragmentation analysis, reverse transcription-polymerase chain reaction (RT-PCR), annexin V-fluorescein isothiocyanate (FITC) staining, and immunoblot analyses were then carried out.

RESULTS

(-)-Epicatechin was found to have cytotoxic activity, and cells treated with this compound had fragmented nuclei, fragmented DNA, and underwent apoptosis. mRNA and protein expression levels of BCL2-associated X protein (BAX) and p53 were up-regulated and those of B-cell lymphoma-2 (BCL2) were down-regulated, while p21 mRNA levels were significantly increased in cells treated with (-)-epicatechin in a concentration-dependent manner.

CONCLUSION

(-)-Epicatechin from B. Sarmienti inhibited colon cancer cell growth and induced apoptosis.

ID3 mediates X-ray-induced apoptosis of keratinocytes through the regulation of β-catenin

BACKGROUND

Ionizing radiation is used to treat many of cancers, however, it also produces unwanted side effect on normal tissues, such as radiodermatitis. We previously established an animal model for radiodermatitis, and found that X-ray irradiation induced the expression of ID3 in hairless mouse skin by cDNA microarray.

OBJECTIVE

The aim of this study is to investigate the functional role of ID3 in X-ray irradiated keratinocytes.

METHODS

Immunohistochemistry, RT-PCR and Western blot were performed to demonstrate the ID3 induction by X-ray irradiation. HaCaT keratinocytes were transduced with the recombinant adenovirus expressing HA-ID3, and then effects on apoptosis were analyzed.

RESULTS

X-ray irradiation increased markedly the ID3 protein level in epidermis of mouse skin. X-ray irradiation also induced the expression of ID3 in HaCaT keratinocytes cultured in vitro, at both mRNA and protein levels. When ID3 was overexpressed by recombinant adenovirus, apoptosis of keratinocytes were induced even in the absence of X-ray irradiation. Furthermore, overexpression of ID3 sensitized X-ray-induced apoptosis. Interestingly, X-ray irradiation significantly reduced the endogenous β-catenin level, which was related with induction of apoptosis. Similarly, overexpression of ID3 led to remarkable reduction in β-catenin level.

CONCLUSION

These results suggest that ID3 plays a role as an apoptosis inducer in response to X-ray irradiation via the regulation of endogenous β-catenin level.

Expression profiling of radiation-induced genes in radiodermatitis of hairless mice

BACKGROUND

Radiation induces many cellular events leading to radiodermatitis.

OBJECTIVES

The aim of this study was to establish a radiodermatitis model using experimental animals, and to examine the expression profile of radiation-induced genes.

METHODS

Hairless mice were irradiated on the dorsal skin; then total RNAs were isolated and microarray hybridizations were performed.

RESULTS

Irradiation with a total of 40 Gy (10 Gy day-1 for four consecutive days) provokes radiodermatitis in the hairless mouse. After microarray analysis, 130 genes that showed upregulation by radiation were selected and organized into four different clusters, depending on the time-kinetic pattern. Classification of these genes into several functional categories revealed that various biological processes were globally affected by radiation. These include transcription regulation, signal transduction, cell communication, cell death regulation and metabolism.

CONCLUSIONS

These results demonstrate the complexity of the transcriptional profile of the radiation response, providing important clues on which to base further investigations of the molecular events underlying radiodermatitis.