Changes in the expression of gallinacins, antimicrobial peptides, in ovarian follicles during follicular growth and in response to lipopolysaccharide in laying hens (Gallus domesticus)

Abstract

The aim of this study was to identify the types of gallinacin genes (GALs) expressed in ovarian follicles and to determine the changes in their expression during follicular growth and in response to lipopolysaccharide (LPS). Follicles at different stages of growth were collected from laying hens (n= 5) and LPS-injected hens (n= 3). The expression ofGALs in the theca and granulosa layers was examined by semi-quantitative RT-PCR. The expression ofGAL-1,-2,-7,-8,-10, and-12in the theca layer andGAL-1,- 8,-10, and-12in the granulosa layer was identified in white and yellow follicles. The expression of these genes was not changed in the theca and granulosa layers during follicular growth except for a decrease in that ofGAL-1in theca. The expression ofGAL-1,-7, and-12in the theca layer of the third largest follicles was increased in response to LPS at a dose of 1 mg/kg body weight and this increase was induced within 3 h and maintained until 12h postinjection. Granulosa layers did not respond to LPS until 12h injection. These results show that six and four types ofGALs are expressed in the theca and granulosa layers of healthy follicles respectively, and their levels do not change with follicular growth except forGAL-1in theca. Elevated levels ofGAL-1,-7, and-12expression in theca in response to LPS suggest that the theca cells expressing theseGALs function to eliminate LPS-containing bacteria.