Efeito do lipopolissacarideo na expressão gênica de células da granulosa do folículo dominante em bovinos

Abstract

This study aimed to evaluate the inflammatory response in serum and follicular fluid before the challenge with lipopolysaccharide (LPS), correlating with estradiol production, PON1 enzyme activity and haptoglobin in blood serum and follicular fluid, expression of genes related to response inflammatory and steroidogenesis in granulosa cells of the dominant follicle. The group receiving LPS had increased rectal temperature (P<0.05; 40.42 ± 0.11) compared to the control group (38.84 ± 0.10), proving the effectiveness of treatment with LPS. The PON1 activity in serum (control: 130.2 ± 5.13 U / ml LPS: 99.62 ± 7.10 U / mL) and follicular fluid (control: 47.25 ± 4.40 U / mL, LPS: 30.57 ± 3.07 U / ml) was higher in the control group compared to LPS group (P<0.05), as a reflection of the inflammatory response. Importantly, PON1activity in the follicular fluid was 50% lower (P <0.05) compared to serum. Gene expression in granulosa cells of genes related to the synthesis of steroid hormones were also evaluated during our experiment and it was observed that the StAR expression was significantly reduced in the group challenged with LPS (~ 90% reduction; P <0.05). The expression of the inflammatory process related genes were also evaluated in granulosa cells and there was a difference regarding TLR4 and TNF (~ 90% reduction, P<0.05). The level of estradiol intrafollicular was not different between the control group and LPS (P=0.24). In conclusion, LPS challenge induces an inflammatory response in the dominant follicle granulosa cells, mediated via TLR4 and resulting in reduction of TNF expression. In addition, this response can change the production of steroid hormones in the long term as the expression of key enzymes in this process (StAR) was drastically reduced