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: CONCLUSION : This study establishes a TAA model by periarterial CaCl ( 2 ) exposure in rats , and demonstrates a significant elevation of expression of MMP - 2 , MMP - 9 , ADAM10 and ADAM17 in the pathogenesis of vascular remodeling .
### Output Text:
CONCLUSION : This study establishes a TAA model by periarterial <span class="chemical">CaCl ( 2 )</span> exposure in rats , and demonstrates a significant elevation of expression of MMP - 2 , MMP - 9 , ADAM10 and ADAM17 in the pathogenesis of vascular remodeling . 