Expression pattern of Toll-like receptors 4 on the reproductive organs and gonadal axis of female rabbits

Systemic and local infections can perturb the reproductive function in humans and animals. Toll-like receptors (TLRs) recognize pathogen-associated molecular patterns expressed by invading pathogens leading to an inflammatory reaction. Lipopolysacharide is the major component of Gram-negative bacteria and can be recognized by TLR4. The objectives of this study were to localize and to determine the expression profile of TLR4 in reproductive organs and gonadal axis of female rabbit. Samples of uterus, oviducts, ovary, hypothalamus and pituitary were collected from 8 healthy does. Our study showed that TLR4 are expressed in all tissues examined, but levels appeared higher in uterus and pituitary than hypothalamus (P < 0.001), ovary (P < 0.05), and oviduct (P < 0.001). The immune-histochemical examination of samples confirmed the presence of TLR4 in genital organs and ovarian axis. In uterus andoviducts this receptor is more expressed in stroma than epithelium and glands, while in ovary is evidenced in stroma and follicles. These results showed that TLR4 is expressed both in genital tract and gonadal axis of the doe suggesting that they can be involved in alteration of reproductive function at different levels. Rabbit may be an excellent animal model to study mechanisms associated with infertility.