protective effect of thiamine on the induced lesions by experimental lead poisoning in gold fish

lead is one of the heavy metal that is very toxic for environment and organisms. lead can inhibits many physiological processes and it is so dangerous for body tissues. in this study, four groups of fish (carassius auratus) 35 in each, were used for experiment. group 1 was as control, in group 2 fishes were exposed to lead acetate at concentration of 8. 5 mg/l, fishes in group 3 and 4 were also exposed to lead acetate in the same concentration of group 2 supplemented with vitamin b1(thiamine) at doses 30mg/l and 60mg/l, for 21 days respectively. tissue specimens including gill, brain, kidney and liver were fixed in 10% buffered formalin, and stained with h&e.; results of histopathological findings evaluated with two non parametric kruskal- wallis test and mann-whitney test. histopathology of brains of fishes in group two, showed hyperemia, privascular edema, prineuronal edema and ischemic cell changes. according to mann-whitney test, hyperemia and edema lesions, the difference between group 2 and 4 was significant. this result showed some efficacy of thiamine at concentration of 60mg/l in prevention of brain lesions caused by lead poisoning. histopathology of kidneys revealed hyperemia, degenerative and necrotic changes, swelling of epithelial cells, hyperplasia of melano- macrophage centers, intranuclear inclusion bodies in epithelial cells. in kidney, goup 2 and 3 showed significant difference in swelling of epithelial cells, intranuclear inclusion bodies and degenerative necrotic changes according to mann-whitney test. in liver, hyperemia, hyperplasia of melano- macrophage centers, hepatocellular vacular degeneration and intranuclear inclusion bodies were observed. in liver, the difference of hyperemia were significant in group 2 and 4. considering the histopathological findings and based on mann-whitney test, non of lesions revealed significant difference in gill. according to the result of this experiment, it seems that thiamine has some degrees of protective effects on lead poisoning lesions in brain, kidney and liver of goldfish, and it seems that the thiamine has a dose depended role dose on lead poisoning in fish.