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Instead , early chronic exposure to Pb disrupted microglia via damage to , loss of , or lack of proliferation of microglia in the developing brains of Pb - exposed animals .
 Chemical: Pb; Chemical: Pb
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: Pb