Glutamine prevents intestinal calcium absorption inhibition triggered by menadione avoiding oxidative stress and apoptotic death of enterocytes

DIAZ DE BARBOZA, GABRIELA EDITH; BENEDETTO, MARIA MERCEDES; TOLOSA DE TALAMONI, NORI GRACIELA

Buenos Aires

Otro; XXIX Reunión Anual de la Asociación Argentina de Osteología y Metabolismo Mineral; 2012

Asociación Argentina de Osteología y Metabolismo Mineral

Glutamine (GLN) is an aminoacid which can restore redox state in different tissues. We showed that menadione (MEN) decreases intestinal Ca absorption triggering oxidative stress and apoptotic death of enterocytes. In this work we explored if GLN could prevent the inhibitory effect caused by MEN on intestinal Ca absorption. Four week old chicks were treated with 1g GLN/kg bw per os and/or with 2.5μmol MEN/kg bw intraperitoneally (60 or 90 min later). Both drugs acted together for 30 min. Controls were treated with vehicle. We measured intestinal Ca absorption by “in situ” ligated loop technique. The activities of superoxide dismutase (SOD) and catalase (CAT) and total glutathione content (GSH) were determined by spectrophotometry. DNA fragmentation was studied by TUNEL and the pro- and anti-apoptotic protein expression by immunohystochemistry. GLN administration 60 or 90 min before MEN injection prevented the fall in intestinal Ca absorption triggered by MEN. GLN avoided the increment of GSH levels and the induction of SOD and CAT activities caused by MEN. GLN prevented the increment in the number of TUNEL positive cells and in the expression of cytochrome c, Fas and FasL induced by MEN. The expression of anti-apoptotic proteins Bcl2 and calbindin D28k decreased after MEN treatment. GLN only prevented the decrease in Bcl2 triggered by MEN. These data suggest that GLN can prevent the reduction in the intestinal Ca absorption caused by MEN, probably by the restoration of control values of GSH content and the activities of SOD and CAT. Besides, GLN arrests apoptosis of enterocytes by blocking the activation of the extrinsic and intrinsic pathways and preserving the expression of Bcl2.