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: In this study , we examined the roles of lipopolysaccharide , a pro - inflammatory and inflammatory factor , treatment in modulating the methamphetamine - induced nigrostriatal dopamine neurotoxicity .
### Output Text:
In this study , we examined the roles of <span class="chemical">lipopolysaccharide</span> , a pro - inflammatory and inflammatory factor , treatment in modulating the <span class="chemical">methamphetamine</span> - induced nigrostriatal <span class="chemical">dopamine</span> neurotoxicity . 