Tumor necrosis factor-alpha as a possible auto-/paracrine factor affecting estrous cycle in the cat uterus

Tumor Necrosis Factor-alpha (TNFα) is a pleiotrophic cytokine, affects either normal or tumor cells, and influences cellular differentiation. TNFα role in female reproduction has been proven to be mediated through an influence on prostaglandin (PGs) synthesis and output. To evaluate the possible role of TNFα in an auto-/paracrine regulation in the cat uterus, mRNA expression coding for TNFα and its receptors (TNFR1 and TNFR2), and TNFα protein content at different stages of the estrous cycle were investigated. Additionally, TNFα involvement in PG secretion at different stages of the estrous cycle was investigated by in vitro tissue culture. Gene expressions coding for TNFα and TNFR1 were the highest at diestrus (P < 0.05). TNFα protein expression was the lowest at interestrus (P < 0.05). Nevertheless, TNFR2 was not affected by the estrous stage. TNFα at a dose of 1 ng/ml significantly increased PGF₂α secretion at estrus (P < 0.01) and PGE₂ secretion at diestrus (P < 0.001) after 12h incubation. Overall findings indicate that TNFα locally produced in the cat’s uterus, stimulates PG secretion in an estrous cycle-related manner.