I already have a Nikon D5200 and I I tried so much to get a clear view of the sky and it didn't work so much.

The camera you have is a fine one to start with. You should spend some time working on technique before you worry about switching to a different camera.

Astrophotography is all about capturing tiny amounts of light compared to daytime photography, but the tradeoffs aren't all that different. You want a long enough exposure that the subject is well exposed, but not so long that noise or motion ruin your shot. In the daytime, you'd worry about the camera or the subject moving; at night you'll have the camera fixed on a solid tripod or other mount, and your chief concern is the motion of the earth creating star trails. In the daytime you'd pick a location with good lighting conditions; at night you want a clear sky with as little light pollution as possible.

There's plenty to learn about astrophotography, and it's worth getting a book or hopping online to find good advice that'll get you started. Doing that will make a much larger difference in your results than changing your gear.

Is there any DSLR specialized for astrophotography?! If so I'd like to know them plus the features needed to do astrophotography.

There are DSLR's that are specialized for astrophotography. Most DSLR's have an infrared filter covering the image sensor, which is helpful for most daytime photography but not necessarily ideal for astrophotography. Some people remove this filter (or have it removed by someone who knows what they're doing) to make their camera more sensitive to IR light, and a few models (Canon 60Da, Nikon D810a) have different filters the allow more IR light. However, if you're not already getting good night sky shots, these cameras aren't going to help you.