Abstract: 6

PROGESTERONE AND INTERFERON-TAU REGULATE MONOCYTE CHEMOTACTIC PROTEIN-1(MCP-1) IN THE OVINE UTERUS.

Eric Asselin^{1 *}, Greg A Johnson^{1 *}, Thomas E Spencer^{1 *}, Fuller W Bazer^{1 *}
Department of Animal Science and Center for Animal Biotechnology and Genomics, Institute of Biosciences and Technology, Texas A&M University System Health Science Center, College Station, TX. ¹

Endometrial leukocytes are believed to play an important role during pregnancy. Since chemokines are important regulators of immune cell activity and trafficking, the objectives were to determine: (1) if MCP-1 was present in the ovine uterus; and (2) factors regulating MCP-1 mRNA expression. A partial endometrial ovine MCP-1 cDNA was cloned by RT-PCR and used in subsequent studies. In study 1, ewes were hysterectomized (n=4/day) on D 1, 3, 5, 7, 9, 11, 13 or 15 of the estrous cycle or D 11, 13, 15, 17 or 19 of pregnancy. Slot blot hybridization analysis of endometrial total RNA revealed that MCP-1 RNA levels did not change during the estrous cycle, but increased (p<0.05, linear) between D 13 and 19 of pregnancy. Using in situ hybridization (ISH), MCP-1 mRNA was localized to immune cells in the subepithelial stratum compactum. Histomorphological studies indicated that the immune cells were probably eosinophils. In study 2, cyclic ewes (n=20) were ovariectomized and fitted with uterine catheters on D5. Ewes received daily intrauterine injections of protein (D 11-25), and steroids (i.m.,D 5-25) of steroids as follows: 1) 50 mg progesterone (P) + 100 mg control proteins(CX); 2) P + 75 mg ZK112,993 + CX; 3) P + recombinant ovine (ro)IFNt (2 × 10⁷ AVU); 4) P + ZK + roIFNt, and were hysterectomized on D 25. Endometrial MCP-1 mRNA levels increased in response to P and the increase was amplified with combined P₄ + roIFN treatment (P<0.05). MCP-1 increase was abrogated with the P receptor antagonist (ZK) treatment.This is the first evidence for regulation of MCP-1 in the uterus and suggest that MCP-1 positive eosinophils may play a role in successful establishment of pregnancy. Supported by USDA 98-35203-6337 (FWB) and MRC fellowship (EA).

    This abstract is being presented on Saturday, July 31 at 2:45 PM at Todd 116.