Abstract
The present study was designed to investigate the therapeutic effects of
melatonin as well as zinc in combination or each one alone against the hepatic
and renal toxicity of lead in male rats.
Five groups of animals were allocated as follows: Group I, includes 12
rats injected subcutaneously with 0.2 ml physiological saline for 60 days; groups
II and III, each includes 12 rats, injected with lead acetate 100 mg/kg/day s.c for
30 days, followed by treatment with intraperotoneal injection of physiological
saline (0.2 ml) or melatonin 30mg/kg/day for the next 30 days. Group IV,
include 12 rats, injected with lead acetate 100 mg/kg/day s.c for 30 days,
followed by treatment with intraperotoneal injection of zinc sulphate 1.5
mg/kg/day for the next 30 days. Group V, includes 12 rats injected with
100mg/kg lead acetate s.c for 30 days followed by treatment with intraperitoneal
injection of 30 mg/kg/day melatonin and 1.5mg/kg/day zinc sulphate for the
latter 30 days. At the end of treatment period, the rats were sacrificed by an overdose (100mg/kg) of thiopental (twenty-four hour after the last injection).
Laparotomies were performed to obtain the livers and kidneys for the
assessment of tissue damage. Oxidative stress parameter (MDA), hemoglobin
content, liver and renal functions, and histological appearance of the studied
organs were evaluated and compared with that of negative and positive controls.
Treatment with melatonin or zinc reverses the damage induced by lead in many
organs and tissues through the reduction of MDA levels in RBCs, liver and
kidneys; in addition to the improvement in the indices of the functions of the organs studied
These findings demonstrated that addition of zinc to melatonin are
capable of further reversing damage of rat tissues caused by successive doses of lead acetate, and animals had restored their organ functions due to combined treatment.
melatonin as well as zinc in combination or each one alone against the hepatic
and renal toxicity of lead in male rats.
Five groups of animals were allocated as follows: Group I, includes 12
rats injected subcutaneously with 0.2 ml physiological saline for 60 days; groups
II and III, each includes 12 rats, injected with lead acetate 100 mg/kg/day s.c for
30 days, followed by treatment with intraperotoneal injection of physiological
saline (0.2 ml) or melatonin 30mg/kg/day for the next 30 days. Group IV,
include 12 rats, injected with lead acetate 100 mg/kg/day s.c for 30 days,
followed by treatment with intraperotoneal injection of zinc sulphate 1.5
mg/kg/day for the next 30 days. Group V, includes 12 rats injected with
100mg/kg lead acetate s.c for 30 days followed by treatment with intraperitoneal
injection of 30 mg/kg/day melatonin and 1.5mg/kg/day zinc sulphate for the
latter 30 days. At the end of treatment period, the rats were sacrificed by an overdose (100mg/kg) of thiopental (twenty-four hour after the last injection).
Laparotomies were performed to obtain the livers and kidneys for the
assessment of tissue damage. Oxidative stress parameter (MDA), hemoglobin
content, liver and renal functions, and histological appearance of the studied
organs were evaluated and compared with that of negative and positive controls.
Treatment with melatonin or zinc reverses the damage induced by lead in many
organs and tissues through the reduction of MDA levels in RBCs, liver and
kidneys; in addition to the improvement in the indices of the functions of the organs studied
These findings demonstrated that addition of zinc to melatonin are
capable of further reversing damage of rat tissues caused by successive doses of lead acetate, and animals had restored their organ functions due to combined treatment.