Effect Of Prenatal Cold Stress On GH-IGF1 Axis And Intestinal Flora In Offspring Of Pregnant Female Rats

Cold stimulation is one of the main environmental stress sources that restrict the development of animal husbandry in the cold regions of the northern China.It can lead to an increased chance of maternal production of weak or stillbirth,resulting in delayed development of offspring,decreased immunity,and decreased resistance to adverse factors.The previous research results of the research group showed that prenatal cold stress caused the decrease of growth hormone levels in the plasma of the weaned offspring,while the liver played an important role in the metabolism of growth hormone.At the same time,prenatal cold stress induced the anxiety-like behavior of the offspring to decrease.Intestinal flora participates in the regulation of body behavior,but the impact of prenatal cold stress on the liver and intestinal flora of the offspring is unclear.The effects of prenatal cold stress on GH-IGF1 axis and intestinal flora of the liver were analyzed,and the corresponding signal transduction pathways were clarified,which provided a scientific basis for the healthy development of animal husbandry in the cold regions of northern China.In order to explore the effect of prenatal cold stress on the GH-IGF1 axis of the offspring liver,this study took the weaned offspring of pregnant rats with prenatal cold stress as the research object and the weaned offspring without cold stimulation of the mother as the control group,and divided them into normal temperature group,normal temperature GH injection group,cold stress group and cold stress GH injection group.On the seventh day after the birth of offspring rats,the GH injection group was injected with GH(0.025 μg/g body weight /2 days),the normal temperature group and the cold stress group were injected with the same dose of normal saline until the end of 21 days after birth,liver tissue samples were collected,and then GHR,IGR1 R,JAK2,STAT3,STAT5 and other related proteins in the liver were detected.The results showed that prenatal cold stress reduced the expression of GHR and IGF1 R proteins in the male offspring liver(P<0.05),and inhibited the JAK2/STAT3 signaling pathway,inducing the up-regulation of the phosphorylation level of STAT5.In order to further investigate the effect of prenatal cold stress on the intestinal flora of pregnant female rats,the feces of male and female weaned offspring in normal temperature group and cold stress group were collected,and 16SV4 region amplicon sequencing was performed.The results showed that prenatal cold stress significantly up-regulated Lactobacillus,Lactobacillus gasseri,Bacteroides and Bacteroides acidifaciens in the intestinal tract of the female offspring.At the same time,prenatal cold stress significantly reduced the intestinal Lachnospiraceae and Prevotellaceae in male offspring.To sum up,prenatal cold stress inhibits the liver GH-IGF1 axis through the JAK2/STAT3 pathway,affects the liver’s metabolism of growth hormone,inhibits the growth and development of offspring,and has a more significant effect on the male offspring.On the other hand,prenatal cold stress changes the composition of the intestinal flora of the offspring,and changes in the flora may affect the behavioral changes of the offspring and the regulation of visceral fat metabolism,and have gender differences.