HEXACHLOROBENCENE TREATMENT INDUCES DIFFERENT RESPONSES TO ISCHEMIA/REPERFUSION INJURY IN MALE RAT HEARTS

BONAZZOLA, PATRICIA; ROMERO CAIMI, GISELLE; ROSÓN, MARÍA INÉS; GORZALCZANY, SUSANA; ALVAREZ, LAURA; CASTILLA, ROCÍO

Mar del Plata, Buenos Aires , Argentina

Congreso; LXI Reunión Anual de la Sociedad Argentina de Investigación Clínica; 2016

Sociedad Argentina de Investigación Clínica

We havepreviously demonstrated that the bio-accumulated organ chlorinade pesticidehexachlorobenzene (HCB) induced hypertension in female rats. This work focuseson HCB subchronic in vivo and acute in vitro effect on male rat heartfunction. For in vivo studies, maleWistar rats were treated 3 times a week with HCB (500mg/kg b.w.) by garbage intubation for 45 days, and hearts were thenextracted and either used for histological analysis or for mechanical andenergy assays. To this end the hearts were arterially perfused at 37 ºC by Langendorff method, electrically stimulated at3 Hz, exposed to 25 min ischemia followed by 45 min. reperfusion whilesimultaneous mechanical and heat measurements were done.  For invitro studies hearts from control rats were treated with HCB (5 µM) for 30min. before ischemic insult. Results: in vivo studies, HCB increased systolic blood pressure in male rats (142 ± 7 vs. 117 ± 2, p<0.01). Histological studiesshowed no alterations in muscular thickness of septum or the edge free of left ventriclebut subpericardial inflammatory lymphocytic infiltrated and subendocardial fociof fibrosis are observed. Hearts from HCB-treated rats showed a decrease in resting pressureduring reperfusion (58.5 ± 4.5 vs. 89.2 ± 6.3 mmHg, p<0.05 at 45 min ofreperfusion) and an improvement of developed pressure (P) expressed aspercentage of preischemic value during post ischemic recovery (46.2 ± 6.0 vs.18.8 ± 2.3%, p<0.001 at 45 min of reperfusion). Total heat production (Ht) revealedno differences from control hearts, so that contractile economy expressed aspercentage of preischemic value (P/Ht%) was higher than control duringreperfusion (67.8 ± 7.2 vs. 35.0 ± 5.1%, p<0.05 at 45 min reperfusion). In vitro pre-treatment with HCB rendered a decrease of 25% inpreischemic values of P but no significant changes in postischemic P, Ht or P/Htwere observed. Conclusion: HCB protects male rat hearts from ischemic insult. Suchprotection is a long term event probably as a response to pesticide-induced hypertension.