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: It is concluded that oxidative tubular damage plays an important role in the VCM - induced nephrotoxicity and the modulation of oxidative stress with erdosteine reduces the VCM - induced kidney damage both at the biochemical and histological levels .
### Output Text:
It is concluded that oxidative tubular damage plays an important role in the <span class="chemical">VCM</span> - induced nephrotoxicity and the modulation of oxidative stress with <span class="chemical">erdosteine</span> reduces the <span class="chemical">VCM</span> - induced kidney damage both at the biochemical and histological levels . 