|Cushman, Robert - Bob|
Submitted to: Midwestern Section of the American Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 11/12/2008
Publication Date: 7/1/2009
Citation: Slattery, R., Clopton, D., Wood, J., Cushman, R., Cupp, A. 2009. Vascular Endothelial Growth Factor (VEGF) mRNA Isoforms are Altered in Bovine Granulosa Cells (GC) by Circulating Progestin Concentrations (P4) and May Indicate Follicle Status and Oocyte Competence [abstract]. Journal of Animal Science. 87 (E-Supplement 3):66 (Abstract # 85).
Technical Abstract: Previously, Melengestrol Acetate (MGA) fed for 14 d (0.5mg/cow/d; < 1 ng/ml P4) resulted in persistent follicles with increased size, decreased number of GC/follicular fluid (FF) volume, and less fertile oocytes. An experiment was conducted to determine effects of circulating P4 on amount of mRNA for pro- and anti-angiogenic vascular endothelial growth factor (VEGF) isoforms in GC of dominant (largest estrogen active; DOM) and subordinate (next largest; SUB) follicles. The hypothesis tested was that DOM developed with MGA will have reduced VEGF proto anti-angiogenic mRNA isoforms in GC compared to controlled intravaginal drug releasing device (CIDR) (control; 4-6 ng/ml of P4). Cows (n = 13) received prostaglandin F2a (PG) on d 1 and 7 and MGA for 14 d or GnRH on d 7 and a CIDR for 7 d (n = 14). On d 14, all cows received PG and CIDR’s were removed. Ovariectomies were conducted 36 h post-PG and GC, FF and blood was collected for analysis. Data were analyzed using PROC MIXED of SAS with mean separation by LSD. MGA DOM (n = 13) were larger (P < 0.001) and had decreased GC:FF ratio (P = 0.06); but, E2: P4 ratio did not differ from CIDR DOM (n = 14). Increased E2 was present in DOM (P < 0.001) compared to SUB (n = 16; 1047.6 ± 137 vs. n = 14; 161.4 ± 140 ng/ml) and P4 was greater (P = .001) in SUB compared to DOM (n = 14; 259.0 ± 44 vs. n = 16; 42.2 ± 43 ng/ml). Angiogenic VEGF164 isoform mRNA tended (P = 0.10) to be increased in DOM compared to SUB. In addition, VEGF165b isoform was greater (P = 0.05) in SUB compared to DOM (n = 14; 10.7 ± 3 vs. n = 16; 2.5 ± 3). Furthermore, VEGF164:VEGF165b mRNA isoform ratio was greater in DOM (n = 16; 1.1 ± 0.2 vs. n = 14; 0.4 ± 0.2; P < 0.05) vs. SUB. CIDR DOM (n = 14) tended (P = 0.08) to have a greater VEGF164:VEGF165b ratio than MGA DOM (n = 12). From these results, VEGF pro- to anti-angiogenic isoform ratio is greater in GC from healthy, estrogenic (dominant), nonpersistent follicles suggesting that ratio of VEGF mRNA isoforms is a good indicator of follicle status and oocyte competence.