Effects Of Feeding Level And Exogenous Leptin Antibody Intervention On Puberty And Endocrine Of Related Hormones Research In Mice

The study was mainly to explore the role and status of leptin in the sexual maturation process in mice, trying to find the link between leptin and sexual maturation by enzyme-linked immunosorbent assay (ELISA) and real-time quantitative PCR (qRT-PCR) to detect. The study consists of two parts, launched by different nutrition levels and exogenous leptin antibody.The restricted feeding test in the first part, one hundred twenty female KM mice (21-day-old) were randomly assigned into four groups, included the voluntary feed intake group and90%,80%and70%of voluntary feed intake groups.To explore the puberty、the relevance between serum levels of leptin and associated hormone secretion and the expression of leptin, Fshr and Lhr mRNA of ovarian in mice of different feed levels. The mice were killed after blood collection by enucleation, the serum samples were stored at-20℃, and the ovarian tissue samples were sent to-80℃ultra-low temperature refrigerator quickly after liquid nitrogen treatment. The results showed that:The serum levels of leptin of feeding80%or70%of ad libitum were significantly reduced (P＜0.01) compared with ad libitum group, the changes in serum content of LH were no significant difference (P>0.05); and the serum content of FSH, TC and TG changes consistent with leptin. The expression of leptin and Fshr mRNA was significantly increased (P＜0.01) in ovarian, contrary to the serum levels of leptin. Puberty weight was significantly reduced (P<0.01), puberty age was prolonged (P>0.05). The puberty weight and indexes of serum of feeding90%of ad libitum were slightly reduced compared with ad libitum group, but there was no significant difference (P>0.05). The expression of leptin and Lhr mRNA were no significant difference (P>0.05) except Fshr mRNA was significantly increased (P＜0.01) in ovarian, puberty age was advanced (P>0.05).The antibody injection test in the second part, one hundred twenty female KM mice (21-day-old) were randomly assigned into four groups, included the normal saline group, high dose group, middle dose group and low dose group. To explore the puberty、 the relevance between serum levels of leptin and associated hormone secretion and the expression of leptin, Fshr and Lhr mRNA of ovarian in mice, which being after the intervention of exogenous leptin. Then, combined with the results of first part, analysed the mechanism of puberty and related hormonal endocrine regulated by leptin in mice.The results showed that:Comparison of leptin antibody-treated and saline-treated mice, the serum levels of leptin was reduced, but no significant difference (P>0.05). The puberty weight was significantly increased (P<0.01), puberty age was no significant difference (P>0.05). The expression of leptin mRNA was increased but no significant difference (P>0.05) in ovarian, regulated by the serum levels of leptin as well as FSH, LH and TC, TG.Combining these results, the decline of dietary nutrition levels and intervention of exogenous leptin antibody will lead to the reduction of serum levels of leptin in mice, thereby causing the serum levels of FSH, LH and TC, TG decreased, the expression of leptin, Fshr and Lhr mRNA increased in ovarian. And thus lead to the postponement of the mice puberty.