Long-term apoptosis-related protein expression in the diabetic mouse ovary

FRAUNHOFFER NICOLAS A.; ABUELAFIA, ANALIA MEILERMAN; BARRIENTOS, MARIANGEL; CIMERMAN, KAREN VERONICA; OLMOS, MARIA FLORENCIA; CHULUYAN, EDUARDO HECTOR; BARRIOS, MARCELA

PLOS ONE

PUBLIC LIBRARY SCIENCE

Lugar: San Francisco; Año: 2018

1932-6203

Emerging evidence has shown that oocytes from diabetic ovaries exhibit delayedmaturation, mitochondrial dysfunction and meiotic defects, which are related increasedapoptosis. The main objective of the present study was to analyze the apoptosispathways activated during follicular loss at multiple time points in a diabetic mousemodel. Twenty BALB/c mice were used in this study, and diabetes mellitus wasinduced by streptozotocin injection. Three diabetic and two control animals weresacrificed on days 15, 20, 70 and 80 posttreatment. The ovaries were then removed;one was used for follicular counting, TUNEL, immunohistochemistry andimmunofluorescence, while the other was used for Western blot analysis. The proteinsstudied were BAX, BCL2, t-BID, FAS, FASL, active caspase 8, active caspase 9 andactive caspase 3. Follicular apoptosis decreased over time, with the highest valuesobserved at 15 days posttreatment. Granulosa cells were positive for active caspase 3,which showed constant expression levels at all time points. FAS, FASL, t-BID andactive caspase 8 showed strong cytoplasmic immunostaining in the oocytes andgranulosa cells of the diabetic mice, with significant increases observed at 15, 20 and70 days posttreatment. BAX expression was slightly higher in the diabetic mouseovaries than in the control ovaries at 15, 20 and 70 days posttreatment, whereas thehighest active caspase 9 expression was at observed 20 days posttreatment. LowBCL2 protein levels were detected in the diabetic mouse ovaries at all time points. Thisstudy describes for the first time the behavior of apoptosis-related proteins in thediabetic mouse ovary and shows not only that the FAS/FASL pathway contributes tofollicular loss but also that antral follicles are the most affected.