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: Neuroactive steroids protect against pilocarpine - and kainic acid - induced limbic seizures and status epilepticus in mice .
### Output Text:
Neuroactive <span class="chemical">steroids</span> protect against <span class="chemical">pilocarpine</span> - and <span class="chemical">kainic acid</span> - induced limbic seizures and status epilepticus in mice . 