Apoptosis and ovarian function: novel perspectives from the teleosts

Area of Science:

• Reproductive biology
• Cellular biology
• Fish physiology

Background:

• Apoptosis is crucial for ovarian function in mammals.
• The role of apoptosis in teleost ovarian function remains largely unknown.
• This study investigates apoptosis in teleost follicular atresia and postovulatory regression.

Purpose of the Study:

• To determine if apoptosis mediates follicular atresia in teleosts.
• To investigate if apoptosis is inducible in vitro under serum-free conditions.
• To compare apoptosis levels in different teleost follicle types and species.

Main Methods:

• Incubation of vitellogenic follicles from rainbow trout and goldfish in serum-free medium.
• Assessment of apoptosis using 3'-end-labeling and TUNEL analysis.
• Evaluation of primary, postovulatory, oocytectomized, and atretic follicles.

Main Results:

• Goldfish follicles exhibited lower DNA fragmentation than trout follicles.
• In trout, postovulatory and oocytectomized follicles were more susceptible to apoptosis than intact vitellogenic follicles.
• Apoptosis was not induced by in vitro incubation in trout follicles, and atretic goldfish follicles showed no change in DNA fragmentation.

Conclusions:

• Apoptosis is involved in teleost ovarian growth and postovulatory regression.
• Apoptosis does not appear to be an early event in teleost follicular atresia.
• In vitro incubation did not induce apoptosis in teleost follicles.