The Effectives On The Concentrations Of Steroid Hormone In Follicular Fluid And The Experssions Of Luteinizing Hormone Receptor Inducced By ACTH Injection In Suhuai Weaned Sows

Stress is the systemic nonspecific response of body to the stressors.Stress has been proved to impair the porcine reproduction soundly.The reproductive,performance of weaned sows can be suppressed by increased secretion of sugar corticosteroid becaused of the activated of hypothalamus-pituitary-adrenal cortex axis in the process of stress.To investigate the mechanism of ovulation failure caused by stress in weaned sows,the effectives of the reproductive performance was studied in the ACTH,induced weaned sows.All ten tested sows(n=10)were fitted with jugular vein catheters on the weaning day and randomLy divided into control group(n=5)and ACTH group(n=5).Three days after surgery,the sows were injected with ACTH or NaCl(1 IU/kg)every 8 h and continued for 7 days,The concentrations of steroid hormone in follicular fluid and cortisol in plasma were determined using ELISA kits.The mRNA translation level of cytochrome P450 side-chain cleavage(CYP11A1),cytochrome P450,17a-hydroxylase(CYP17A1),cytochrome P450 aromatase(CYP19A1),steroidogenic acute regulatory protein(StAR),3?-hydroxysteroid dehydrogenase(3?-HSD)and LHR were quantified by Real-time quantitative PCR.The protein expressions of CYP17A1,CYP19A1,LHR and 3?-HSD were detected by immunohistochemistric staining.The apoptosis of granulosa cells were detected by TUNEL.The results showed that 40%of the tested sows appear ovulation failure and the time of oestrus was delyed after ACTH injection.Compared to the control group the weight of ovary was light.The concentration of cortisol in plasma was significantly increased(P<0.01)and concentrations of estradiol and androstenedione in follicular fluid were significantly reduced(P<0.05).The enzymatic activity of AST and CK was enhanced,and the concentrations of glucose,total cholesterol,triglycerides,total protein were elevated compared to control group.The transcriptional levels of CYP17A1,CYP19A1,LHR and 3p-HSD were reduced(P<0.05)and their corresponding protein expressions of CYP17A1,CYP19A1,3?-HSD and LHR were also decreased(P<0.05).The results suggest that,during the process of stress which induced by ACTH injection,the decline of genes and their correspongding proteins expressions of steroid synthetase reduced by inductions of cortiosl in plasma will influence the steroid hormone synthesis and follicle development.Increased the metabolism process of animal body,resulting in a decrease of material reserves,in turn,affects the sow reproductive performance.The normal ovulation of weaning sows will be influenced by the lower levels of stersoid hormones and the lower expression of LHR.