Serdar Yardimci

Histopathological and Ultrastructural Examination of the Rat Conjunctiva after Exposure to Tobacco Smoke

Exposure to tobacco smoke can cause irritation of the conjunctiva. We conducted this study to identify the effect of tobacco on rat conjunctiva. Animals were divided into experimental and control groups and we exposed the experimental group to tobacco smoke. Control group rats inhaled only room air. Spectrophotometric analysis of the smoke-air mixture revealed that many toxic substances were present in this compound. We found very high levels of plasma thiocyanate after exposure to smoke in experimental group animals but no increase in the control group. So, this data indicates that these animals inhaled smoke effectively in our method. After 3 months conjunctivas were examined by light and electron microscopy. In the experimental group, conjunctivas were thinned, atrophied and microvillous projections and desmosomal connections were absent in comparison with the control conjunctivas. This pathologic change is very similar to conjunctival response to chronic irritants of any type.

A Possible Mechanism of X-Ray–Induced Injury in Rat Lens

PURPOSE X-ray and other radiation can cause cataract, but the pathogenic mechanism is largely unknown. The aim of this study was to investigate the accumulation of iron in the x-ray-exposed rat lens and its relationship to lens injury. METHODS Fifty male Wistar rats were divided randomly into five groups of 10. Groups 2 and 4 rats were sham-exposed, groups 3 and 5 were x-ray-treated, and group 1 served as control. X-ray radiation and sham exposure were performed in a similar manner. After 10 and 30 days of exposure, a lens from each rat in groups 2 and 3, and 3 and 5, respectively, were analyzed by flame atomic absorption technique for the assessment of metal content. RESULTS Significantly decreased zinc and increased iron and calcium concentrations were detected in the lens samples of groups 3 and 5 compared with groups 2 and 4 and controls. Similar results were obtained comparing groups 5 and 3. CONCLUSIONS We propose that x-ray exposure may cause toxic cell injury of the rat lens via Fenton metals catalyzed damage. Initial lens membrane damage in the radiolytic phase may permit the access of iron resulting in lens damage.