Author/Editor		Lenasi, Helena
Title		Effect of subchronic exposure to mainstream cigarette smoke on endothelium-dependent vasodilation in rat arteries
Translated title		Vpliv subkronične izpostavljenosti cigaretnemu dimu na od endotelija odvisno vazodilatacijo arterij podgane
Type		članek
Source		Zdrav Vestn
Vol. and No.		Letnik 74, št. 7-8
Publication year		2005
Volume		str. 415-21
Language		eng
Abstract		Abstract - Background. Cigarette smoking is reported to impair endothelium-dependent vasodilation. The aim of the present study was to assess the effect of 30-day exposure to mainstream cigarette smoke on vascular reactivity of rat abdominal aorta, carotid, renal and mesenteric artery. Separately, the NO-mediated and the EDHF-mediated, endothelium-dependent vascular relaxations were determined. Methods. Two groups of »Whistar Kyoto« rats were exposed to mainstream cigarette smoke (2 hours/day, 5 days/week for 30 days) and to fresh conditioned air, respectively. Rats were sacrificed on the second day after the last exposition to cigarette smoke. Vascular reactivity studies were performed on isolated, endothelium-intact, phenylephrine preconstricted rat artery rings. Cumulative concentration-relaxation curves to acetylcholine (ACh) were obtained in the absence and presence of the endothelial NO synthase (eNOS) inhibitor N nitro L-arginine (L-NA) and the cyclo-oxygenase (COX) inhibitor diclofenac, respectively. After washing period of 1 hour, vessels were exposed either to the intracellular superoxide scavenger tiron, to the cytochrome P450 (CYP) inhibitor miconazole or the Na-K-ATPase inhibitor ouabain before being preconstricted with phenylephrine and determining the concentration-response curve to ACh. Results. ACh induced concentration-dependent relaxations. In none of the vessels investigated did we observe a significant difference in the relaxations obtained in arteries from control rats and rats exposed to cigarettee smoke. (Abstract truncated at 2000 characters)
Summary		Izhodišča. Znano je, da kajenje dolgoročno okvari arterijsko steno ter povzroča aterosklerozo. Številne raziskave so pokazale, da je ena od zgodnjih sprememb okvara endotelijske funkcije, ki naj bi nastala kot posledica spremenjenega razmerja med endotelijskimi vazodilatatorji, kot so dušikov oksid (NO), prostaciklin, endotelijski hiperpolarizirajoči faktor (EDHF), in vazokonstriktorji, kot so endothelin-1, produkti ciklooksigenaze (COX) in superoksidni anioni. Vendar pa natančni mehanizmi, ki vodijo do sprememb endotelija, še niso poznani; prav tako ni še povsem raziskano, kako hitro omenjene spremembe nastanejo. Prav zato je bil naš namen raziskati, če subkronična izpostavljenost cigaretnemu dimu (30 dni) že okvari endotelijsko funkcijo nekaterih arterij podgane. Posebej smo želeli ovrednotiti vpliv cigaretnega dima na endotelijsko vazodilatacijo, ki jo posreduje NO, ter endotelijsko vazodilatacijo, ki jo posreduje EDHF. Metode. Aktivno kajenje smo simulirali tako, da smo podgane vrste "Whistar Kyoto" izpostavili neposrednemu cigaretnemu dimu (2 uri/dan, 5 dni/teden, 30 dni). Da bi se izognili zaznavanju akutnih sprememb, smo od zadnje izpostavljenosti cigaretnemu dimu do izvajanja meritev žilne reaktivnosti počakali dva dni. Po žrtvovanju živali smo izolirali abdominalno aorto, karotidno, mezenterično in ledvično arterijo. Žilno reaktivnost smo preučevali v kopeli za izolirane organe. Obročke izoliranih žil z ohranjenim endotelijem obeh skupin podgan smo aktivno skrčili z dodatkom noradrenalina (30 nM do 300 nM) ter nato z dodajanjem naraščajočih koncentracij acetilholina (ACh, 1 nM-10 uM) izzvali relaksacijo obročkov; po izpiranju smo obročke inkubirali z dodatkom znotrajceličnega "lovilca prostih radikalov", tirona (1 mM, 40 minut) ter ponovili osnovni protokol izvajanja relaksacije. (Izvleček prekinjen pri 2000 znakih)
Descriptors		TOBACCO SMOKE POLLUTION ENDOTHELIUM, VASCULAR VASODILATION NITRIC OXIDE ACETYLCHOLINE NOREPINEPHRINE AORTA CAROTID ARTERIES MESENTERIC ARTERIES RENAL ARTERY ENDOTHELINS RATS, INBRED WKY