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: Evaluation of cardiac troponin I and T levels as markers of myocardial damage in doxorubicin - induced cardiomyopathy rats , and their relationship with echocardiographic and histological findings .
### Output Text:
Evaluation of cardiac troponin I and T levels as markers of myocardial damage in <span class="chemical">doxorubicin</span> - induced cardiomyopathy rats , and their relationship with echocardiographic and histological findings . 