Role of Nigella sativa seed oil on corneal injury induced by formaldehyde in adult male albino rats.

Formaldehyde is frequently used in occupational environments, its toxicity concerns to all who work closely with it such as anatomists. Nigella sativa is an amazing herb with a rich historical and religious background; its seeds are the source of its active ingredients. The purpose of the present study was to evaluate the role of Nigella sativa oil on corneal injury induced by formaldehyde in adult male albino rats. Forty adult male albino rats were divided randomly to four groups 10 rats each: I - Control group, II - Formaldehyde exposed group, III - Nigella sativa oil group (40 mg/kg/day) via intragastric tube daily for 2 weeks and IV - Formaldehyde and Nigella sativa group. Rats were sacrificed with ether, the corneas were extracted, one processed for haematoxylin and eosin stain and the other was used for transmission electron microscopic examination. Our results in group II revealed marked disorganisation, erosion, vacuolation and necrosis of epithelial cells with loss of parts of epithelial layer. Large congested invasion of blood vessels with separation and disorganisation of stromal fibrils. The corneas of group IV showed intact layers of epithelial cells with appearance close to control group. Star shaped cells (limbal stem cells) were obviously noticed in basal and intermediate layer with intact Bowman's membrane. Stroma showed regular parallel collagen, limbal stem cells were also noticed in group III. We concluded that Nigella sativa oil can ameliorate the toxic changes of formaldehyde on rat corneas. (.