7673
Pb exposure increases the Fe content in the old - aged rats ' brain , which might be not subjected to DMT1 mediating , but may be associated with the decrease expression of FP1 .
 Chemical: Pb; Chemical: Fe
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: Pb; Chemical: Fe