Abstract: Toll Like Receptors (TLRs) play an important role in innate and adaptive immunity, however the expression of TLR4 in piglets of different ages is still unknown. In this study, the tissue samples of 11 organs including heart, liver, spleen and so on were collected from 32 piglets of 4 different ages (8, 18, 30 and 35 days old). Real-time PCR was used to compare and analyze the expression of TLR4 both in different tissues and growing periods of piglets which aimed at discussing the function of TLR4 in immune responses in the piglets of development periods as well as showing the relationship between the expression level and piglets sensitivity to different subtypes E. coli. The results showed that TLR4 gene was expressed in all the tissues and high levels of expression were detected in immune organs such as lung, lymph node, thymus gland and spleen. In addition in 8 days old piglets, the expression level of TLR4 in immune organs such as lung, spleen, kidney and thymus gland was relatively high. Then the whole expression quantity continually increased reaching the highest level in 35 days old of weaning period, especially in thymus gland and lung. The expression of TLR4 in thymus gland in 35 days old piglets was significantly higher than that in piglets of other ages (p<0.05) and the expression in lung was significantly higher than that in 8 days old piglets (p<0.05). The results indicated that TLR4 played the extremely important role in connecting the natural immunity and specific immunity. Besides, TLR4 not only played an important role in both immune response and general resistance to lung diseases but also could have a significant control function in preventing weaning piglets from being infected by E. coli F18.
Z.Y. Pan, Z. Chen, L. Liu, Y.Z. Cao, K.Z. Xie, J.S. Yang, X.G. Huang, S.L. Wu and W.B. Bao, 2011. Differentiation of Porcine TLR4 Gene Expression in Piglets of Different Ages. Journal of Animal and Veterinary Advances, 10: 2312-2316.