Application of Prohibitin Immunohistochemistry to Rat Livers Treated with Methapyrilene Hydrochloride

An immunohistochemical staining method for prohibitin, a 30-kDa protein located in the inner membrane of mitochondria, is used for detection of mitochondria on formalin-fixed paraffin-embedded sections. Methapyrilene hydrochloride (MP), which is known to increase mitochondria in periportal hepatocytes, was administered once by oral gavage to male rats at a dose of 100 mg/kg. Hypertrophy with eosinophilic granules was noted in the periportal hepatocytes treated with MP. Immunohistochemical staining with prohibitin antibody demonstrated a positive reaction to eosinophilic granules. Electron microscopy showed an increased number of mitochondria in the periportal hepatocytes treated with MP compared to the control. Although electron microscopy is a useful tool to detect ultrastructural changes, an immunohistochemical examination with anti-prohibitin antibody is a simple and easy method for detecting cytoplasmic mitochondria quantitatively.