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: In the current study , we investigated whether a physiological intervention by feeding 40 % high fat diet ( HFD ) , which induces obesity in male Sprague - Dawley rats ( 250 - 275 g ) , sensitizes to doxorubicin - induced cardiotoxicity .
### Output Text:
In the current study , we investigated whether a physiological intervention by feeding 40 % high <span class="chemical">fat</span> diet ( HFD ) , which induces obesity in male Sprague - Dawley rats ( 250 - 275 g ) , sensitizes to <span class="chemical">doxorubicin</span> - induced cardiotoxicity . 