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 contrast , the dexamethasone - treated hypertensive eyes had thickened trabecular beams , decreased intertrabecular spaces , thickened juxtacanalicular tissue , activated trabecular meshwork cells , and increased amounts of amorphogranular extracellular material , especially in the juxtacanalicular tissue and beneath the endothelial lining of the canal of Schlemm .
### Output Text:
In contrast , the <span class="chemical">dexamethasone</span> - treated hypertensive eyes had thickened trabecular beams , decreased intertrabecular spaces , thickened juxtacanalicular tissue , activated trabecular meshwork cells , and increased amounts of amorphogranular extracellular material , especially in the juxtacanalicular tissue and beneath the endothelial lining of the canal of Schlemm . 