Exponent in bibliography - Microsoft word plugging

Hello, I get some problem so fix exponent in my bibliography, i had so edit them manually. I got a lot of article with like Na+ K+ H+ ... in their title, is there any solution to fix the + as exponent in the mendeley desktop? Such as for italics maybe? E.g Lucu Č, Pavičić J, Ivanković D, et al (2008) Changes in Na+/K+-ATPase activity, unsaturated fatty acids and metallothioneins in gills of the shore crab Carcinus aestuarii after dilute seawater acclimation. Comp Biochem Physiol - A Mol Integr Physiol 149:362–372. doi: 10.1016/j.cbpa.2008.01.026 The + should be in exponent Thank you in advance! Dimitri