20982
We investigated the effects of different concentrations of strontium on collagen content , type II collagen , insulin - like growth factor ( IGF - 1 ) and matrix metalloproteinase ( MMP ) - 13 expression in rat cultured articular chondrocytes in vitro .
 Chemical: strontium
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: strontium