Publication: Sıçanda endotoksemiye bağlı ince barsak kontraktilite değişiklikleri ve reaktif oksijen metaboliti oluşumu üzerine Alfa-Melanosit stimülan hormon (Alfa-MSH)’un etkileri
Abstract
Çalışmada sıçanda endotoksine bağlı ince barsak hasarı, motilite değişiklikleri ve periton kaynaklı uyarılmış nötrofillerden serbestlenen reaktif oksijen metabolitleri (ROM) üzerine -MSH'nın etkilerini araştırmak amaçlanmıştır. Lipopolisakkarit (LPS; 20 mg/ kg) veya serum fizyolojik (kontrol) veya LPS öncesi -MSH (2.5-50 g/ sıçan) uygulanan sıçanlar LPS'den 4 saat sonra öldürüldüler. Farklı gruplarda, orta-ileumdan hazırlanan longitudinal kas striplerinin in vitro organ banyosunda karbakol (10-10-10-3M)'e yanıtları poligraf aracılığıyla kaydedildi. Farklı deneyde, sıçanların periton sıvısından izole edilen nötrofil süspansiyonlarına, LPS (1-20 g/ ml) veya LPS 5 g/ ml (LPS-5) ile birlikte PMA (1 M) veya LPS-5 PMA varlığında -MSH (10-12-10-6M) eklendi. Nötrofillerdeki ROM'lerinin ölçümü kemiluminesans (KL) yöntemi ile yapıldı. LPS grubunda ince barsak transit indeksi (%) kontrole göre anlamlı derecede gecikti (p<0.05) ve makroskopik lezyon skorları da kontrole göre anlamlı şekilde arttı (p<0.01), bu etkiler -MSH tedavisiyle değişmedi. LPS grubunda artan doku yaş ağırlıkları (p<0.05), -MSH (2.5 g/ sıçan) tedavisiyle anlamlı şekilde azaldı (p<0.01). LPS grubu kas striplerinde, karbakol'e (10-6M) bağlı kasılma cevabı kontrolden düşük bulunurken (p<0.05), bu etki -MSH varlığında değişmedi. LPS'nin 5 g/ ml dozu, luminol-aracılı KL ölçümlerini kontrole göre anlamlı şekilde arttırdı (p<0.05), bu artış ortama PMA eklenmesiyle daha da yükseldi (p<0.001). -MSH'nın artan konsantrasyonları bu etkiyi değiştirmedi. LPS-5+PMA grubunda lusigenin-aracılı KL ölçümleri kontrole göre anlamlı şekilde arttı (p<0.01), bu artış -MSH'nın (10-8M ve 10-6 M) ortama eklenmesi ile belirgin şekilde azaldı (p<0.01). Ayrıca, -MSH (10-9M ve 10-6M) ksantin-ksantin oksidaza bağlı lusigenin-aracılı KL ölçümlerinde süperoksit anyonu oluşumunu azalttı (sırası ile; p<0.05 ve p<0.01). Bu verilere göre -MSH, LPS'ye bağlı ince barsak kontraktilite ve motilite değişiklikleri ile makroskopik hasar üzerine anlamlı bir etki göstermemekle birlikte, uyarılmış nötrofillerden süperoksit üretimini inhibe etmektedir. THE EFFECTS OF -MELANOCYTE STIMULATING HORMONE ( -MSH) ON ENDOTOXEMIA-INDUCED INTESTINAL CONTRACTILITY CHANGES AND REACTIVE OXYGEN METABOLITE PRODUCTION IN THE RAT
We investigated the effects of -MSH on endotoxemia-induced intestinal damage, motility disturbances and reactive oxygen metabolites (ROM) released from activated rat peritoneal neutrophils. Lipopolysaccharide (LPS; 20 mg/ kg) or physiologic saline (control) or -MSH (2.5-50 g/ rat) before LPS was administered to rats and they were decapitated 4 hours after LPS. In different groups, responses of longitudinal muscle strips (from mid-ileum) to carbachol (10-10-10-3M) in in vitro organ baths were recorded using a polygraph. In another experiment, LPS (1-20 g/ ml) or LPS 5 g/ ml (LPS-5) and PMA (1 M) or -MSH (10-12-10-6M) in the presence of LPS-5+PMA were added to neutrophil suspensions obtained by peritoneal lavage from the rats. ROM measurements from neutrophils were determined by chemiluminescence (CL) technique. In LPS group intestinal transit index (%) was delayed compared to control (p<0.05) and macroscopic lesion scores were higher than control (p<0.01), -MSH treatment did not change this effects. Increased intestinal wet weights in the LPS group (p<0.05) were reduced with -MSH (2.5 g/ rat) treatment (p<0.01). In muscle strips of the LPS group, contractile response to carbachol (10-6M) was reduced compared to control (p<0.05), this effect was not changed in the presence of -MSH. 5 g/ ml dose of LPS increased luminol-enhanced CL values (p<0.05), this increase was further elevated when PMA was added to the medium (p<0.001). Increased concentrations of -MSH did not change this effect. In LPS-5+PMA group, lucigenin-enhanced CL values were increased compared to control (p<0.01) and this effect was reversed by -MSH (10-8M and 10-6M) (p<0.01). In xhantine-xhantine oxidase-mediated lucigenin-enhanced CL, -MSH (10-9M and 10-6M) reduced superoxide anion production (p<0.05 and p<0.01, respectively). Our data suggest that, -MSH does not have any significant effect on LPS-induced changes in intestinal contractility and motility changes and macroscopic lesion, whereas it inhibits superoxide production from activated neutrophils.
We investigated the effects of -MSH on endotoxemia-induced intestinal damage, motility disturbances and reactive oxygen metabolites (ROM) released from activated rat peritoneal neutrophils. Lipopolysaccharide (LPS; 20 mg/ kg) or physiologic saline (control) or -MSH (2.5-50 g/ rat) before LPS was administered to rats and they were decapitated 4 hours after LPS. In different groups, responses of longitudinal muscle strips (from mid-ileum) to carbachol (10-10-10-3M) in in vitro organ baths were recorded using a polygraph. In another experiment, LPS (1-20 g/ ml) or LPS 5 g/ ml (LPS-5) and PMA (1 M) or -MSH (10-12-10-6M) in the presence of LPS-5+PMA were added to neutrophil suspensions obtained by peritoneal lavage from the rats. ROM measurements from neutrophils were determined by chemiluminescence (CL) technique. In LPS group intestinal transit index (%) was delayed compared to control (p<0.05) and macroscopic lesion scores were higher than control (p<0.01), -MSH treatment did not change this effects. Increased intestinal wet weights in the LPS group (p<0.05) were reduced with -MSH (2.5 g/ rat) treatment (p<0.01). In muscle strips of the LPS group, contractile response to carbachol (10-6M) was reduced compared to control (p<0.05), this effect was not changed in the presence of -MSH. 5 g/ ml dose of LPS increased luminol-enhanced CL values (p<0.05), this increase was further elevated when PMA was added to the medium (p<0.001). Increased concentrations of -MSH did not change this effect. In LPS-5+PMA group, lucigenin-enhanced CL values were increased compared to control (p<0.01) and this effect was reversed by -MSH (10-8M and 10-6M) (p<0.01). In xhantine-xhantine oxidase-mediated lucigenin-enhanced CL, -MSH (10-9M and 10-6M) reduced superoxide anion production (p<0.05 and p<0.01, respectively). Our data suggest that, -MSH does not have any significant effect on LPS-induced changes in intestinal contractility and motility changes and macroscopic lesion, whereas it inhibits superoxide production from activated neutrophils.