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    Cadmium and iron accumulation in rat lens after cigarette smoke exposure and the effect of vitamin E (alpha-tocopherol) treatment
    (TAYLOR & FRANCIS INC, 1999) Avunduk, AM; Yardimci, S; Avunduk, MC; Kurnaz, L
    Purpose. Cadmium accumulation in the lens has been implicated in cataractogenesis of chronic smokers. This study was planned to evaluate whether or not in vivo cigarette smoke exposure causes cadmium accumulation in rat lens, and possible protective effect and mechanism of alpha-tocopherol (vitamin E) treatment on cataractogenesis. Methods. 28 male Wistar rats were randomly divided into four equal groups. Group 3 and 4 rats were exposed to cigarette smoke over ninety consecutive days, and Group 1 and 2 rats were treated in a similar fashion but exposed only to room air. Additionally, vitamin E was given to Group 2 and 4 rats. Results. Significantly higher iron levels were observed in the lenses of Group 3 rats compared to other groups. With respect to cadmium, Group 3 and 4 rats had significantly higher levels compared to Group 1 and 2 rats. Although vitamin E treatment prevented iron accumulation in Group 4 rats, it had no effect on cadmium concentrations. Distinct histopathological changes observed in Group 3 rats were not present in Group 4 rats. Conclusion. Our study demonstrates that in vivo cigarette smoke exposure causes accumulation of cadmium in rat lens and IM vitamin E treatment does not affect this accumulation. The protective effect of vitamin E treatment on smoke exposed rat lens seems to be mediated by blockage of iron accumulation in the lens.
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    Cataractous changes in rat lens following cigarette smoke exposure is prevented by parenteral deferoxamine therapy
    (AMER MEDICAL ASSOC, 1999) Avunduk, AM; Yardimci, S; Avunduk, MC; Kurnaz, L
    Objectives: To test whether iron accumulation in the lens following cigarette smoke exposure is the principal mechanism in smoke-related cataractogenesis and to assess the possible protective effect of deferoxamine mesylate treatment against lenticular degeneration with in vivo exposure to cigarette smoke. Methods: Thirty-two male Wistar rats were randomly divided into 4 equal groups. Groups 3 and 4 rats were exposed to cigarette smoke for I hour each day for 90 consecutive days, and groups 1 and 2 rats were treated in a similar manner but exposed only to room air. In addition, deferoxamine was given subcutaneously to groups 2 and 4 rats. Both eyes of all the animals were then enucleated and 1 eye prepared for histopathological examination. The fellow eye was used to measure iron, calcium, zinc, and cop-per levels. Results: Significantly higher iron and calcium and lower zinc levels were observed in the lenses of group 3 rats compared with those in the other groups. Similar comparisons performed between groups 1 and 2, 1 and 4, and 2 and 4 did not show any significant difference. Copper concentrations did not differ between groups. Distinct histopathological changes in the anterior lens epithelium, such as hyperplasia, hypertrophy, and epithelial multilayering, and the presence of swollen epithelial cells overlying the posterior lens capsule, observed in group 3 rats, were not present in the other groups. Conclusions: Cataractogenesis following cigarette smoke exposure in rats was associated with the accumulation of iron, and concurrent deferoxamine therapy prevented such cataract formation. Clinical Relevance: Our results may apply to human cataract formation associated with cigarette smoking, so such pathogenesis may be prevented by concurrent parenteral deferoxamine treatment Clinical studies are needed, however, to determine the value of this suggestion.
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    Etanercept treatment in the endotoxin-induced uveitis of rats
    (ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, 2004) Avunduk, MC; Avunduk, AM; Oztekin, E; Baltaci, AK; Ozyazgan, Y; Mogolkoc, R
    This study was conducted to investigate therapeutic value of a soluble tumor necrosis factor-alpha (TNF-alpha) receptor, etanercept, in a rat model of endotoxin-induced uveitis (EIU). Forty-two inbred male Lewis rats were divided into seven equal groups. 200 mug of Escherichia coli 055:1355 lipopolysaccharide, (LPS) was injected in one hind footpad of the Groups 2, 3, 4, 5, 6, and 7 rats. Group 5, 6, and 7 rats also received subcutaneous etanercept 24 hr prior to LPS injection at a dose of 0(.)4 mg kg(-1). Group 1 rats were used as controls. Eight, 24, and 48 hr after treatment clinical uvetis scores (miosis, iris hyperemia, and hypopyon) were assessed by a masked observer and the rats were euthanized. Neutrophil leukocytes, CD8 +, CD4 +, and CD45RO + cells in the anterior uveal tissue were counted either after hematoxylin-eosin or monoclonal antibody staining. TNF-alpha. levels were also measured in the aqueous humor samples by an ELISA method. Etanercept treatment significantly improved clinical uveitis scores at all examination points compared to the LPS injected animals. The improvement was almost complete expect for the miosis score, since no significant difference was detected between the controls and LPS + Etanercept treated animals at all examination points. Cell counts were also at significantly lower levels in LPS + Etanercept treated animals at all examination points, except for CD8 + and CD45RO + cell counts at 24 hr examination point. There was no significant difference between the controls and LPS + Etanercept treated animals at all examination points as with CD4 + and CD45RO + cell counts at 48 hr. Our data showed that etanercept had a definite effect on the treatment of EIU. Further studies should clarify its efficacy on clinical uveitis conditions. (C) 2004 Elsevier Ltd. All rights reserved.
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    Prevention of lens damage associated with cigarette smoke exposure in rats by alpha-tocopherol (Vitamin E) treatment
    (ASSOC RESEARCH VISION OPHTHALMOLOGY INC, 1999) Avunduk, AM; Yardimci, S; Avunduk, MC; Kurnaz, L; Aydin, A; Kockar, MC; Delibasi, T
    PURPOSE. TO evaluate the possible protective effect and mechanism of cu-tocopherol (vitamin E) treatment on lens degeneration associated with in vivo exposure to cigarette smoke and to further clarify the role of iron in cigarette smoke-generated lens damage. METHODS. Twenty-eight male Wistar rats were randomly divided into four equal groups. Rats in groups 3 and 4 were exposed to cigarette smoke for 1 hour each day over 90 consecutive days, and rats in groups 1 and 2 were treated in similar fashion but only exposed to room air. Additionally, vitamin E was given to the rats in groups 2 and 4 via intramuscular route. At the end of the study, both eyes of ail the animals were enucleated; one eye was prepared for histopathologic examination, and the fellow eye was used for the measurement of iron and calcium levels. RESULTS, Significantly higher iron and calcium levels were observed in the lenses of group 3 rats than in other groups. Similar comparisons performed between groups 1 and 2, groups 1 and 4, and groups 2 and 4 did not show any significant difference. Distinct histopathologic changes in the anterior lens epithelium, such as hyperplasia, hypertrophy, epithelial multilayering, and the presence of epithelial cells over posterior lens capsule, observed in group 3 rats were not present in other groups. CONCLUSIONS. Cataractogenesis after cigarette smoke exposure was associated with an accumulation of iron and calcium in the rat lens, and vitamin E supplementation protected such accumulations and cataractogenesis.