In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: Part A , for eight rats in each group brain injury was evaluated by staining tissue using 2 , 3 , 5 - triphenyltetrazolium chloride and edema was evaluated by microgravimetry .
### Output Text:
Part A , for eight rats in each group brain injury was evaluated by staining tissue using <span class="chemical">2 , 3 , 5 - triphenyltetrazolium chloride</span> and edema was evaluated by microgravimetry . 