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: Our data showed ADR induced 4HNE - protein adducts in mitochondria at the same time point as when mitochondrial injury initially appeared .
### Output Text:
Our data showed <span class="chemical">ADR</span> induced <span class="chemical">4HNE</span> - protein adducts in mitochondria at the same time point as when mitochondrial injury initially appeared . 