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: Elevation of ADAM10 , ADAM17 , MMP - 2 and MMP - 9 expression with media degeneration features CaCl2 - induced thoracic aortic aneurysm in a rat model .
### Output Text:
Elevation of ADAM10 , ADAM17 , MMP - 2 and MMP - 9 expression with media degeneration features <span class="chemical">CaCl2</span> - induced thoracic aortic aneurysm in a rat model . 