title: Expression of caspase-2, -3, -8 and -9 proteins and enzyme activity in the corpus luteum of the rat at different stages during the natural estrous cycle.
abstract: Apoptosis is associated with the regression of the corpus luteum (CL) in many species. Since caspases play a central role in apoptosis, we studied several initiators (-2, -8, and -9) and the main effector (-3) caspase in the CL during the estrous cycle of the rat. Two different populations of CL (old and new) were identified on ovaries at estrus and diestrus II (DII). Diminished (P < 0.05) luteal progesterone content and P450scc levels suggested that functional luteolysis occurred between the new CL at DII and old CL at estrus, whereas the decline (P < 0.05) in luteal weight indicated that structural regression was occurring between old CL at estrus to DII. Immunostaining for caspase-2 in luteal and endothelial cells appeared to increase as the luteal phase progressed, peaking at DII in the old CL. However, caspase-8 and -9 immunostaining showed little change with a slight increase at estrus in the old population. Notably, caspase-3 staining appeared to peak at DII in the new CL. Enzyme activity of caspase-9 increased (P < 0.05) in the new CL at DII, followed by that of caspase-2 and -3 in old CL at estrus. Caspase-8 activity did not change at any stage. The number of apoptotic cells increased at DII in the old CL. These results suggest an important role for this protease family during early events of luteolysis in the rat estrous cycle.
authors.affiliation: Instituto de Biología y Medicina Experimental (IBYME-CONICET), Departamento de Quiímica Biológica, Facultad de Ciencias Exactas, Universidad de Buenos Aires, Vuelta de Obligado 2490, C1428 ADN, Buenos Aires, Argentina.
authors.forename: Marina C
authors.initials: MC
authors.lastname: Peluffo
authors.forename: Leonardo
authors.initials: L
authors.lastname: Bussmann
authors.forename: Richard L
authors.initials: RL
authors.lastname: Stouffer
authors.forename: Marta
authors.initials: M
authors.lastname: Tesone
mesh_terms: D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western / Q000379:methods; D053143:Caspase 2 / Q000032:analysis; D053148:Caspase 3 / Q000032:analysis; D053181:Caspase 8 / Q000032:analysis; D053453:Caspase 9 / Q000032:analysis; D020169:Caspases / Q000032:analysis / Q000378:metabolism*; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000032:analysis; D003338:Corpus Luteum / Q000201:enzymology*; D030762:Estrous Cycle / Q000502:physiology*; D005260:Female; D007150:Immunohistochemistry / Q000379:methods; D020287:In Situ Nick-End Labeling; D011374:Progesterone / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D011374:Progesterone; D002786:Cholesterol Side-Chain Cleavage Enzyme; D053143:Caspase 2; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases