ABSTRACT
Chromium is one of the most studied chemicals linked to occupational hazards and is a proven toxin, mutagen and carcinogin. People are exposed to chromium compound in a wide variety of situations as it is commonly used in industrial chrome plating, welding, paining, metal finishes, steel manufacturing, alloy, cast iron and wood treatment. So, this study aimed to evaluate the cytotxicity of hexavalent chromium on rat corneas using light and scaning electron microscopic examinations. Ten adult albino rats were used as a control group, whereas twenty adult albino rats were treated with 25 and 2.5 mg/kg hexavalent chromium by intraperitoneal [ip] injection for 7 days respectively. Examination of the control rat cornea demonstrated that, it consisted of five layers. The outer surface was stratified squamous non-keratinized eqithelium with polygonal shape and surface microvilli. After seven daily dose of 25-mg/kg hexavalent chromium adminnistration, the examined corneal specimens revealed increased corneal thickness and loss of cellular demarcation of corneal epithelium with cleft formation and few microvilli. There were cytoplasmic vacuolation and nuclear changes. Also there was loss of the normal stromal lamellar architecture and various empty spaces. Moreover, after 90 days of chromium toxicity there was irregular corneal surface with marked patchy epithelial loss and multiple surface ostia. Also, there was morphological alteration of the surface microvilli and intercellular focal disruption. The Bowman's layer was lost. The corneal stroma showed marked loss of lamellar architecture and empty spaces. Corneal vascularization was also seen with inflammatory infiltrates. So, the present study concluded that, hexavalent chromium is very toxic to the cornea especially after prolonged exposure causing visual impairment and loss