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

The molecular mechanisms of erectile dysfunction with aging are unclear. Re cent studies have suggested that growth factors may play a role in the etio logy of erectile dysfunction. This present study was designed to test the h ypothesis that gene expression of various growth factors such as TGF alpha, TGF beta 1, TGF beta 2, TGF beta 3, IGF and NGF modulate with aging in rat penile tissues. For this purpose, total RNA was extracted from young and o ld 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 fact ors were quantified by using p-actin as an internal standard. The results o f these experiments suggest that: (1) young and old rat penile tissues expr essed mRNA transcripts for TGF alpha, TGF beta 1, TGF beta 2, TGF beta 3, I GF and NGF; (2) TGF beta 1 gene expression was significantly increased in o ld rat penile tissues as compared to young; (3) mRNA transcripts for NGF an d TGF beta 3 were significantly lower in old rat penile tissues as compared to young; and (4) TGF alpha, TGF beta 2 and IGF mRNA expression did not ch ange in young and old rat penile tissues, These results suggest that the di fferential gene expression for various growth factors in young and old rat penile tissues may be important in understanding the pathophysiology of ere ctile dysfunction associated with aging.