Doing research and having publications is better than having no research and no publications, even when applying DO. Truthfully, some DO schools will weigh it more heavily than others, but I seriously doubt some will not care at all. Maybe some will not care that it is research, but it will carry itself as at least a valuable experience or extra curricular activity to even those schools. So basically it can only help your application, and it's awesome that you have done research/had publications because this will carry on with you and be valuable when you apply for residency IMO.