TGFB1 and streptococcal pneumonia: These findings further confirm that high activity of TGF-β1 may contribute to the pathogenesis of TS and suggest that captopril and losartan exert their preventive effects on the Streptococcus pneumonia-induced TS via down-regulation the expression of TGF-β1, which may be one possible explanation for the histological melioration of the middle ear mucosa and the partly recovery of hearing function.