I think its a downtuned E to a D, but I'm not sure. If it sounds better to you, 
play a 6-8 instead of 8-10 in the second part and then open E. 
 
G|----7-7p5-------------------------------| 
D|----------7-----------------------------|X4 
A|-5----------8-10-8-10-8-5---------------| 
D|----------------------------------------| 
 
G|----------------------------------------| 
D|--5-5p3-0-------------------------------|X2 
A|----------------------------------------| 
D|----------8-10-8-10-8-0-----------------| 
 
G|----7-7p5-------------------------------| 
D|----------7-----------------------------|X2 
A|-5----------8-10-8-10-8-5---------------| 
D|----------------------------------------| 
 
G|-----------------------------------7-5-3-------| 
D|-7-7-5-0-7-7-0-5-7-5-5-5-5-5-3-0---------5-3-0-| 
A|-----------------------------------------------| 
D|-----------------------------------------------|