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: PURPOSE : This study was designed to establish a rat model of thoracic aortic aneurysm ( TAA ) by calcium chloride ( CaCl ( 2 ) ) - induced arterial injury and to explore the potential role of a disintegrin and metalloproteinase ( ADAM ) , matrix metalloproteinases ( MMPs ) and their endogenous inhibitors ( TIMPs ) in TAA formation .
### Output Text:
PURPOSE : This study was designed to establish a rat model of thoracic aortic aneurysm ( TAA ) by <span class="chemical">calcium chloride</span> ( <span class="chemical">CaCl ( 2 )</span> ) - induced arterial injury and to explore the potential role of a disintegrin and metalloproteinase ( ADAM ) , matrix metalloproteinases ( MMPs ) and their endogenous inhibitors ( TIMPs ) in TAA formation . 