SMAD2 and diabetes mellitus: Icariin has numerous potential applications in different fields of medicine However, it is best known for its putative role in potentiating sexual function by inhibition of PDE5 [22,23], We found that ICA II could alter corpus cavernosum fibrous-muscular pathological structure in DM rats which could be regulated by the TGFβ1/Smad2/CTGF and NO-cGMP signaling pathways [17].