Apoptosis in canine corpus luteum during spontaneous and XXXX -induced luteal regression.

@entity44494 @entity1420 @entity46926 @entity3009
Spontaneous luteal regression and @entity3009 -induced luteolysis in bitches were evaluated by measuring the apoptotic index for DNA fragmentation and the relative level of @entity46926 gene expression in ovaries removed from nine untreated nonpregnant bitches at selected times during diestrus and in nine pregnant bitches after 1 day of administering abortive doses of a @entity44494 -analog gel formulation given intravaginally at selected times during gestation. Nonpregnant diestrus was divided into three periods (early, mid and late) based on vaginal cytology and plasma @entity1420 concentration. Pregnant bitches were treated with a @entity44494 -analog gel at corresponding stages of pregnancy (early, mid and late) and evaluated by ultrasound. Another eight pregnant bitches were similarly studied and serum @entity1420 concentrations were determined after 1, 2, 3 or 4 days of @entity44494 -analog gel. Corpora lutea obtained by ovariohysterectomy were analyzed for apoptotic internucleosomal DNA fragmentation relative to that in a control cell line (U937), using an apoptotic DNA ladder kit and gel electrophoresis and for relative expression of the pro-apoptotic @entity46926 gene by RT-PCR and electrophoresis. In nonpregnant bitches, the DNA fragmentation apoptotic index was greater in late than in early diestrus (P < 0.01). The index after 1 day of @entity44494 -analog gel was higher in early pregnant bitches than in early diestrus bitches (P < 0.05); it was highest in midpregnancy (P < 0.05). The degree of apoptosis was related to the number of times @entity44494 -analog gel was administered. @entity46926 mRNA was detected in the corpus luteum (CL) and @entity46926 expression increased from early to middiestrus in nonpregnant subjects (P < 0.05). Potential elevation in @entity46926 due to @entity44494 -analog gel treatment in pregnancy was only significant in relation to normal diestrus during early pregnancy (P < 0.01). In conclusion, we inferred that the effects of endogenous or exogenous @entity3009 on CL life span in bitches involved increases in apoptotic activity and that increased apoptosis was implicated in normal luteal regression in nonpregnant bitches.
