Differential gene expression of growth factors in young and old rat penile tissues is associated with erectile dysfunction

Abstract

The molecular mechanisms of erectile dysfunction with aging are unclear. Recent studies have suggested that growth factors may play a role in the etiology of erectile dysfunction. This present study was designed to test the hypothesis that gene expression of various growth factors such as TGFα, TGFβ1, TGFβ2, TGFβ3, IGF and NGF modulate with aging in rat penile tissues. For this purpose, total RNA was extracted from young and old rat penile tissues and the gene expression for these growth factors was determined by differential reverse-transcriptase-polymerase chain reaction (RT-PCR) using specific oligonucleotide primers. mRNA levels of growth factors were quantified by using β-actin as an internal standard. The results of these experiments suggest that: (1) young and old rat penile tissues expressed mRNA transcripts for TGFα, TGFβ1, TGFβ2, TGFβ3, IGF and NGF; (2) TGFβ1 gene expression was significantly increased in old rat penile tissues as compared to young; (3) mRNA transcripts for NGF and TGFβ3 were significantly lower in old rat penile tissues as compared to young; and (4) TGFα, TGFβ2 and IGF mRNA expression did not change in young and old rat penile tissues. These results suggest that the differential gene expression for various growth factors in young and old rat penile tissues may be important in understanding the pathophysiology of erectile dysfunction associated with aging.