Study On The Effect Of Maternal Obesity On Male Offspring Fertility And Its Mechanisms

Objective: Maternal obesity leads to poor health outcomes in offspring,but the effects of maternal obesity on male offspring fertility and its possible mechanisms are unclear,and the induction of maternal obesity by high-fat diet provides a scientific basis for the fetogenic origin of reduced male fertility based on the DOHa D theoryMethods: After 8 weeks of feeding,the mice in the high-fat diet group that exceeded 25% of the average body mass of the low-fat diet group were defined as obese mice,and the mice in both groups were mated with normal male mice of the same age.After successful mating,both groups were fed with the same diet and the offspring were divided into Maternal Obesity(MOB)and Normal Control(CON)groups at birth.After the second batch of female mice gave birth to obese litters,the rest of the methods were the same as those of the first batch,and the mice were treated with 0.15 mg/L metformin drinking water in the maternal obese group at 4 weeks of age,and the diet and drinking water in the control group and the remaining maternal obese group were kept unchanged,and the mice in each group were executed at 8 weeks of age for extraction,and then subsequent experimental tests were conducted:(1)the glucose metabolism status of the mice was examined before extraction;(2)the testes of the mice at(2)HE staining of testicular tissues at 3 and 8 weeks of age to evaluate the degree of testicular tissue integrity;(3)semen quality of the submice under light microscopy;(4)detection of sex hormone levels in the testicular tissues of the submice using Elisa;(5)transmission electron microscopy of the cells in the testicular tissues;(6)immunofluorescence detection of ROS in the testicular tissues to assess oxidative stress in the testicular tissues;(7)use of q PCR,Western Blot and immunohistochemistry to detect the expression level of spermatogonial markers and assess spermatogonial cell function;(8)transcriptome sequencing of testis tissues from day 1 of birth versus 8 weeks of age to analyze the difference in transcriptome levels in testis tissues of submunicans;(9)validation of BMP2 expression in testis tissues of submunicans;(10)in vitro validation of BMP2 gene function using GC-1 spg cell line to verify the function of BMP2 gene;(11)to verify the molecular mechanism using GC-1 cells and testicular tissues of daughter rats;(12)to give metformin treatment to maternally obese daughter rats to assess whether metformin could alleviate the decrease in semen quality caused by maternal obesity.Results: Our results showed that there was a long-term increase in body mass in the offspring of the maternally obese group compared to the control group,with significant differences in body weight at weeks 1,2 and 6,and a significant decrease in testicular mass at adulthood;a significant decrease in sperm semen concentration,sperm motility and sperm forward motion rate,and a significant increase in sperm caudal malformation rate and a significant increase in total sperm malformation rate;maternal obesity did not cause testicular tissue damage in the offspring at weaning(3 Maternal obesity did not cause testicular tissue damage at the time of weaning(3 weeks of age),but caused testicular tissue damage in the adult offspring,with a significant decrease in the number of spermatogonia and mesenchymal cells in the germinal epithelium;microstructure showed lipid accumulation and swelling of the endoplasmic reticulum in mesenchymal cells,incomplete connection between supporting cells and other cells,and cavitation of mitochondria in spermatogonia;maternal obesity showed a significant decrease in testosterone and luteinizing hormone levels and a significant increase in estradiol levels.Maternal obesity also caused a significant decrease in testosterone and luteinizing hormone levels and a significant increase in estradiol levels,which led to a significant increase in ROS levels and Nrf2 expression in the offspring testes,resulting in oxidative stress in the offspring testes.Maternal obesity caused a significant decrease in the expression of Nanog,SALL4 and c-kit genes and a significant increase in the expression of FOXO1 gene,indicating that the differentiation function of spermatogonia was impaired,and there were significant differences in the transcriptome expression of testicular tissue genes in maternal obese groups,mainly in the inflammation-related pathways at day 1 of neonatal life and in the development-related The expression of BMP2/ SMAD1 was significantly downregulated in mice of maternal obesity group,and the apoptosis rate increased significantly and proliferation was significantly inhibited after disturbing BMP2 expression in GC-1 cells;after metformin treatment in maternal obese offspring at 4 weeks of age,the number of interstitial cells in testicular tissue increased,the number of vacuoles inside the germinal tubules decreased,the morphology inside the germinal tubules was relatively The expression of c-kit,SALL4 and Nanog genes,which were significantly down-regulated in the testes of maternally obese offspring was increased.Conclusion: Maternal obesity causes decreased offspring semen quality and may be responsible for impaired spermatogonial differentiation through the BMP2/ SMAD1 pathway,resulting in decreased offspring fertility,and metformin may mitigate the reproductive damage caused by maternal obesity in the offspring.This study focuses on the long-term effects of damage early in life on the postnatal period,providing new insights into the adverse effects of maternal obesity on offspring health,new ideas for global male fertility decline,and a new scientific basis for preventive measures to improve population quality and disease.