How has Oscar Wilde explored the corruption of the human soul in the Picture of Dorian Gray

Any analysis of The Picture of Dorian Gray must start with a recognition that the novel is in some sense autobiographical. Because Oscar Wilde was gay or bisexual, he lived a double life in Victorian England, and eventually was tried and imprisoned for his "immoral" behavior. In the nineteenth century there was, in fact, "underground" literature, but Wilde was a very public and famous person, and, as the feminist author Kate Millet wrote in her book Sexual Politics, Wilde "wanted to publish and to shine." Therefore Dorian Gray can be seen as a novel in which Dorian's homosexuality is implicit, veiled, and, in keeping with the morality of the time, associated with crime and degradation. Perhaps it was Wilde's own latent guilt (impossible not to have in that repressed era) about being gay that made him identify Dorian's behavior with moral corruption.
Dorian's cruel rejection of Sybil after she gives an embarrassingly bad performance in Romeo and Juliet is the first downward plunge of his "soul." He is aware that Sybil loves him, but he allows the judgement of Lord Henry and his other friends to override his own feeling for Sybil. He later regrets his behavior and intends to marry her, but when he learns that she has committed suicide, this news paradoxically leads him to begin the "immoral" lifestyle into which Lord Henry has been trying to lead him all along. The supernatural mechanism by which the portrait both "ages" and shows the corruption in Dorian's soul, while his own face continues to look both young and innocent, facilitates Dorian's descent into a new and sordid world, in which he not only gives free reign to his sexual desires, but also apparently uses drugs and engages in blackmail.
The ultimate step in Wilde's exploration of this corrupted soul is the murder of Basil, which Dorian commits as a kind of climax to his whole life of crime and as an inevitable result of his downward spiral. It is ironic, but not surprising, that he should blame Basil for his own descent, thinking that the picture Basil painted is what has caused him, Dorian, to become unhinged. It is also a corollary to Dorian's "sins" that instead of acknowledging his own responsibility for his crimes, he blames Basil as the one who has made him a "victim." And finally, Dorian mistakenly thinks that he can be redeemed by destroying the portrait itself.
The last scene is a puzzle, for it implies that there is essentially no difference between the picture and the man. The destroyed portrait becomes the destroyed human being, as the servants find Dorian, an old withered man, dead with a knife in his heart. Although Wilde has infused the book with a "moral" message, the ending is another example of the eternal theme of illusion vs. reality, and what difference there is, if any, between the two.