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: To elucidate the possible role of the kinin B1 receptor ( B1R ) during the development of DOX cardiomyopathy , we studied B1R knockout mice ( B1R ( - / - ) ) by investigating cardiac inflammation and apoptosis after induction of DOX - induced cardiomyopathy .
### Output Text:
To elucidate the possible role of the kinin B1 receptor ( B1R ) during the development of <span class="chemical">DOX</span> cardiomyopathy , we studied B1R knockout mice ( B1R ( - / - ) ) by investigating cardiac inflammation and apoptosis after induction of <span class="chemical">DOX</span> - induced cardiomyopathy . 