[ effect of low concentration of lead acetate on learning ability and memory of rats during infancy and adulthood]

Numerous observations in clinical and preclinical studies indicate that the developing brain is particularly sensitive to lead [PB]'s pernicious effects. The effects of low concentrations of lead on neurodevelopment are complicated. Lead acetate can disrupt both the CNS activity and neurons development. The present study was carried out to assess the effect of low level lead exposure on learning and memory by active avoidance learning. This experimental study was conducted at the Islamic Azad University of Parand in 2008. Eight groups of NMRI rats [9 rats in each group] [weight 220 +/- 30 gr] consisting of six experimental groups [3 after infancy and 3 adult groups] were exposed to low concentrations of lead for 45 days. The drinking water of the experimental groups was replaced by 0.05%, 0.1% and 0.2% of lead acetate solution whereas the two control groups received distilled water. The results were analyzed using the SPSS software and student t-test. In this study, the learning and memory tests showed no significant differences between experimental groups [infancy and adulthood] and infancy control and adult control in number of shocks for 0.05% concentration of lead acetate. The memory test showed an increase in number of shocks for 0.1% and 0.2% concentration of lead acetate in adult groups and an increase in number of shocks for 0.2% concentration of lead acetate in infancy groups [P<0.05]. The learning test showed an increase in number of shocks for 0.2% concentration of lead acetate in infancy groups [P<0.05]. Mechanisms of lead poisoning in the CNS are not clear; and it as been suggested that lead exposure during life alters the granule cell neurogenesis and morphology in the hippocampus of infant or young adult rats

[Protective effect of thiamine on the induced lesions by experimental lead poisoning in gold fish [carassius auratus]]

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 and 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 melanomacrophage 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 melanomacrophage 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

[ therapeutic effects of oral administration of garlic extract and tablet on experimentally lead acetate poisoning in mouse]

To study the therapeutic effects of garlic extract and tablet on lead poisoning in mouse. Experimental study. Eighty mature male mice with 22-25g body weight. Mice were divided into 8 groups of 10 mice each. All groups received lead acetate [5mg/kg of bady weight] for 21 weeks and after then treated daily for another 4 weeks as follows: group A1, 500mg/kg fresh garlic; group A2, 250mg/kg fresh garlic; group A3, 125mg/kg fresh garlic; group B1, 1/4 Garlet tablet per kg body weight [Eq. to 500 mg fresh garlic]; group B2, 1/8 Garlet tablet per kg body weight [Eq. to 250 mg fresh garlic]; group B3, 1/16 Garlet tablet per kg body weight [Eq. to 125 mg fresh garlic]; group C, 5mg/kg lead acetate and group D did not received any thing in both the first 4 and the second 4 weeks. These results showed that daily administration of fresh garlic [preferably 250-500 mg/kg] or Garlet tablet [1/4 of one garlet tablet per kg body weight] can have therapeutic effects on mice with chronic lead administration. Result showed that garlic and garlet tablets [in a lower grade] have the ability to reduce the lead residues in soft tissues as well as bone in chronic lead poisoned mouse. So, it can be concluded that garlic can be used for lead poisoning therapy in mouse and probably in human and other animals. Moreover, fresh garlic or garlet tablet in aforementioned dose could be used in areas with lead pollution