2011 YÜksek lisans tez özetleri

The role of melatonine on aluminum induced rat small intestine toxicity

Aluminum is one of the widely found metals on Earth. Due to the industrial developments and contamination, nowadays aluminum is much more started to be taken into human body by food, water, air and variety of drugs. It has been shown in a number of studies that aluminum causes oxidative stress by free radical production and lipid peroxidation in body tissues and as a result of this it has been seen damage on target organs. Besides, there are also some literature showing that aluminum may have role in some inflammatory diseases which were emerged as a result of mucosal damage in intestines. Although there are a number of studies on aluminum toxicity, damage mechanisms caused by aluminum has not been explained yet.

Oxidative stress due to the broken balances of prooxidant/antioxidant in biological systems is correlated with a variety of pathological cases. Organism defense itself with antioxidant agents against free radicals showing prooxidant effect. Melatonin (N-acetyl-5-methoxytryptamine) is a powerful antioxidant which is secreted from pineal gland and decrease free radicals. Moreover, melatonin has the ability of increasing the activations and expressions antioxidant enzymes. Various studies have shown that melatonin has a protective role on tissue damages. In our study we aimed to put forward with histological, immunohistochemical and ELISA (enzyme-linked immunosorbent assay) methods that the mechanisms of aluminum-induced damage and whether melatonin has a protective role on this damage or not.

In this study, 40 male Wistar albino rats were used and were divided into five groups. The first group as a control: serum physiologic, the second group as a control of melatonin: ethanol+serum physiologic, the third group: melatonin, the fourth group: aluminum sulfate (Al₂(SO₄)₃ ) and the fifth group: aluminum sulfate (Al₂(SO₄)₃ ) and melatonin injected three times a week for one month. Tissue samples from jejunum were fixed with Bouin solution for histological examinations. Tissue sections from paraffin blocks stained with Hematoxylin & Eosin (HE), Masson’s trichrome and enforced Periodic Acid Schiff (PAS) reaction. Tissue sections were fixed with formalin and were prepared for immunohistochemical examinations of metallothionein (MT) and Ki-67. In biochemical methods myeloperoxidase (MPO) and total glutathione (GSH) levels were determined by ELISA.

Aluminum caused histological degenerative changes on small intestine tissues. We observed that increase of MT positive crypt cells and decrease of Ki-67 positive crypt cells. Also aluminum caused increase on MPO levels and decrease on GSH levels. When melatonin was applied, these findings showed similar results with values of the control groups. In consequence, we can say that melatonin has protective effects on aluminum-induced small intestine toxicity.