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: We conclude that : 1 ) administration of rhIGF - I improves growth and GFR in rats with chronic PAN nephropathy and 2 ) unlike rhGH , long - term use of rhIGF - I does not worsen renal functional and structural injury in this disease model .
### Output Text:
We conclude that : 1 ) administration of rhIGF - I improves growth and GFR in rats with chronic <span class="chemical">PAN</span> nephropathy and 2 ) unlike rhGH , long - term use of rhIGF - I does not worsen renal functional and structural injury in this disease model . 