Wnt11 and Dlk1 Proteins Expression in the Testicular Parenchyma of Letrozole-Treated and Vehicle-Treated Pigs

• Main Author: Soto, Delia Alba
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01-01-2014
• Subjects: Animal sciences; Developmental biology
• ISBN: 1321364016; 9781321364019

Successful spermatogenesis in higher vertebrates requires Sertoli cell function. Each Sertoli cell is capable of supporting a defined number of germ cells; thus, the testis size and sperm output rely on the total number of Sertoli cells. The in vivo administration of Letrozole, a non-steroidal inhibitor of aromatase activity, suppresses estradiol levels and increases the size of the Sertoli cell population. The pathways that regulate Sertoli cell proliferation and whether estrogen affects this process remain unclear. Increased Wnt11 and Delta-like protein 1 (Dlk1) gene expression have been associated with the aromatase inhibitor treatment that leads to an increased Sertoli cell population in the boar. Wnt11 is member of the Wnt family of highly conserved glycoproteins. The Wnt11 protein is recognized for its role in cardiogenesis, cell proliferation, adhesion/migration, and differentiation. Dlk1 belongs to the Notch/Delta/Serrate family of epidermal growth factor-like repeat-containing proteins, and Dlk1 is believed to function as a growth factor, maintaining the proliferative state of undifferentiated cells. This project evaluated the presence of Wnt11 and Dlk1 proteins in testes from boars. Littermates were randomly assigned to receive letrozole (0.1 mg /kg bw) weekly, from the one week of age, or the control vehicle; with a total of four littermate pairs evaluated. Treatments were administrated until testes were retrieved at five weeks of age. Using western blot analyses, the presence of Wnt11 and Dlk1 proteins in the testes was confirmed. Immunolocalization of Wnt11 protein was variable among litters. Although treatment did not significantly alter estimated testicular content of Wnt11 or Dlk1, protein estimates were highly correlated with RNAseq analyses of gene expression. Estimates of protein content may be too variable or changes in protein levels may be too gradual to be detected. Additional studies will be needed to elucidate if Wnt11 and Dlk1 pathways have a role in Sertoli cell proliferation.