18763
Retinas of oxygen - induced retinopathy ( OIR ) mice ( a model for PDR ) had higher TCF7L2 and VEGFA mRNA levels than controls ( P = 2 . 9E - 04 for TCF7L2 ; P = 1 . 9E - 07 for VEGFA ) .
 Chemical: oxygen
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: oxygen 
Answer:
 Chemical: oxygen