Expression Of Nerve Growth Factor And Its Receptors In Hierarchical Follicles And Oviducts Of Hens

Nowadays, egg production is one of efficient industries in the livestock industry that is closely related to people’s lives. The poultry, oviparous animals, have no estrous behavior, pregnancy and lactation. If the condition is appropriate, they can complete follicular development, ovulation and fertilization in a continuous period. For the characteristics, techniques such as immunohistochemistry and Real time-PCR were applied to investigate the protein and mRNA level of NGF and its receptors in ovaries, prehierarchical follicles, dominant follicles and oviducts during different laying periods.1. Expression of nerve growth factor and its receptors in hierarchical follicles of hens during different laying periodTo investigate the expression of NGF and its receptors in the ovary and hierarchical follicles of hens during different laying period,5groups of83,130,30,450and550days old laying hens were examined for the study by immunohistochemistry and fluorescence quantitative PCR. The results demonstrated that immunoreactions for NGF and its two receptors were not detected in the ovary of83-days old laying hens. NGF and p75was stained mainly in thecal cells and granulosa cells of prehierarchical follicles during different laying period, except in granulosa cells prehierarchical follicles of450days, while TrkA was observed in thecal cells of prehierarchical follicles of hens, including granulosa cells in prehierarchical follicles of230days, SWF of450days as well as SWF and SYF of550days. Meanwhile, NGF and its receptors mRNA were expressed in all hierarchical follicles of hens during different laying period, and expressions of NGF and its receptors TrkA and p75in SYF of230days were significantly higher than that in130,450and550days, while expression level in dominant follicles reached the peak in230days and then decreased thereafter. Furthermore, there was a positive correlation that with the laying age increased, serum level of estrogen/progesterone increased as the immunostaining for NGF/TrkA in SYF, respectively. Taken together, these results indicated that NGF may play a role in the growth, development and ovulation of hierarchical follicles, which coordinates with estrogen and progesterone to affect the laying rate in different laying periods.2. Expression of nerve growth factor and its receptors in oviducts of hens during different laying periodIn order to investigate the effect of NGF and its receptors in oviducts of hens during different laying period,5groups of83,130,230,450and550days old laying hens were examined for the study by immunohistochemistry and fluorescence quantitative PCR.The results demonstrated that immunoreactions for NGF and its two receptors were not detected in the oviducts of83-days old laying hens, while NGF and its receptors TrkA and p75were located in infundibulum, magnum and isthmus of oviducts in130,230,450and550days old laying hens. Moreover, with the laying age increased, the positive cell density showed a trend of "low-high-low", In addition, NGF and its receptors mRNA were expressed in all hierarchical follicles of hens during different laying period, and expression of NGF and p75in isthmus of230days was significantly higher than that in130and450days. However, expression of TrkA in magnum and isthmus of230days was lower than that in130and450days. These results implied that NGF may play a role in the growth and development of oviducts and participate in modulating the progress of laying eggs.In conclusion, follicular development and laying eggs were a complex physiological process, which could be regulated by multiple factors. Our results showed that NGF may play a role in the growth and development of prehierarchical follicle and oviducts, which coordinates with estrogen and progesterone. However, the specific regulation mechanisms still need further research.