Comparative histology of wild-type and p53-deficient medaka (Oryzias latipes): nephrotoxic effect of ultraviolet A radiation
Ultraviolet radiation (UVR) is an ecological factor that directly affects terrestrial organisms through immunity suppression or internal organs damage. The present work was done to assess the effects of UVA on kidney of both WT type and P53 mutant medaka (Oryzias latipes) and also to compare between them which one can be more tolerant against the effect of UVA. Four groups of fish were divided into: control group (1);Cwt & Cp53), kept for 3 days without UVA exposure, group (2); (1wt & 1p53); UVA-exposed fish exposed daily to UVA for 1hr/day for 3 days, group (3); (2wt & 2p53); UVA-exposed fish exposed daily to UVA for 2hr/day for 3 days, and group (4); (3wt & 3p53); UVA-exposed fish exposed daily to UVA for 3hr/day for 3 days. Samples of tissue were obtained 24 hr after UVA exposure. The most obvious histopathological changes occurred by UVA radiation on the kidney tissues of both of medaka (WT& p53) were the high vacuolation of tubular cells followed by necrosis. The tubular segments lost their normal tubular shape and their cells showed a clear cytoplasm (malignant cells) and appear like network structure. Necrosis of lymphoid tissues and many of brown pigments were sporadically seen in interstitial lymphoid tissues. Meanwhile shrinkage of glomerulus, diminution of +PAS reaction and increase the amount of collagenous fibers was observed. Our results confirmed the harmful effects of UVA radiation on kidney tissue of both WT type and p53 mutant medaka. The WT type medaka was the most affected than of p53 mutant medaka.