Is WordPress uses PDO in its recent version?

Easy to anser that one: No. It doesn’t.

I believe (but I could be corrected by one of the dev team) that that’s because any move to PDO would break 1,000’s of themes and plugins that use the standard mysql_* functions. Even though these are depricated, the devs still need to worry about backward compatibility, and there’s a whole lot of sites out there that would fall over in a very big way if that sort of large-scale change was made.