Animal Reproduction Science 138 (2013) 282–291 Contents lists available at SciVerse ScienceDirect Animal Reproduction Science journal h om epa ge: www.elsevier.com/locate/anireprosci Cleavage of poly (ADP-ribose) polymerase-1 is involved in the process of porcine ovarian follicular atresia Quanwei Wei, Fangxiong Shi ∗ Laboratory of Animal Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China a r t i c l e i n f o Article history: Received 31 October 2012 Received in revised form 13 January 2013 Accepted 28 February 2013 Available online 14 March 2013 Keywords: PARP-1 Cleaved-PARP-1 Caspase-3 Cleaved-caspase-3 Follicular atresia Porcine a b s t r a c t Ovarian follicle atresia is a common phenomenon in vertebrate ovaries and this process is characterized by follicular wall degeneration. The molecular mechanism underlying folli- cle atresia is apoptotic granulusa cell death; however, the exact signaling pathway is still unclear. PARP-1, the founding member of the poly (ADP-ribose) polymerase (PARP) family, plays an important role in a large variety of physiological processes. Although its cleavage has recently been implicated in a variety of physiological and pathological processes, its role in the process of follicular atresia is not yet completely defined. We identified the cleav- age of PARP-1 involved in the process of follicle degeneration, which is known as “follicular atresia”, both from in vivo models and cell culture data. The results from immunohistochem- istry (IHC) showed that cleaved PARP-1 was mainly located in apoptotic granulosa cells (GCs); and the expression of PARP-1 and caspase-3 were decreased in apoptotic granulosa cells (GCs). The results from western blotting showed that PARP-1 expression was signif- icantly decreased in atretic follicles compared with healthy (H) follicles, and the cleavage of caspase-3 (17 kDa) significantly increased in atretic follicles. Along with the cleavage of caspase-3, the expression of cleaved PARP-1 (24 kDa) product was significantly increased, which confirmed caspase-3 activation. Serum starvation led to a reduction in PARP-1 and an increase in cleaved PARP-1 (24 kDa) and caspase-3 (17 kDa), suggesting that caspase-3 was activated under the stress of withdrawal of growth factors, in accordance with the in vivo study. In the present study, the concentrations of estradiol (E2) and progesterone (P4) as well as the P4/E2 (P/E) ratio were combined with morphological features to deter- mine follicular classification. In summary, the present study demonstrated that cleavage of PARP-1 by caspase-3 was involved in the process of granulosa cell apoptosis. PARP-1 may through its cleavage act as a critical regulator in the process of porcine follicular atresia. Our results identified that cleavage of PARP-1 by activated (cleaved) caspase-3 may serve a key role in controlling follicular atresia through granulosa cell degeneration. These findings should prove helpful in understanding the regulatory mechanisms controlling follicular development and atresia. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Poly (ADP-ribose) polymerase-1 (PARP-1), is the first protein to be described as a member of the poly ∗ Corresponding author. Tel.: +86 25 84399112. E-mail address: fxshi@njau.edu.cn (F. Shi). (ADP-ribose) polymerase (PARP) family, which contains 18 distinct proteins in humans. PARP-1 is a nuclear, NAD + - dependent enzyme present in eukaryotes (Altmeyer and Hottiger, 2009; Kim et al., 2005; Yang et al., 2010). It is believed that PARP plays a role in two main pathways of cell death: apoptosis and necrosis (Kim et al., 2005; Virag and Szabo, 2002). Most of the reports on PARP and apo- ptosis focus on the major PARP isoform, PARP-1, which 0378-4320/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.anireprosci.2013.02.025