11253
In vivo , chronic oral exposure to Acrolein ( 2 . 5 mg / kg / day by intragastric gavage for 8 weeks ) induced mild cognitive declination and pyknosis / atrophy of hippocampal neurons .
 Acrolein
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 Acrolein