Materials and methods
Induction of rat model
Animals : male wistar rats purchased from the national laboratory animal center,mahidol university, eighing etween 275-300g were maintained under standardized laboratory conditions (temperature 22+-2c,12/12hr light/dark cycle)for one week acclimatization.they were allowed free access to drinking water and commercial standard rodent pellets. the study protocol including number of animal use was approved by the animal ethics committee of the facully of medicine,chiang mai university.
Inducton of renal and liver injuries by cadmium chloride :six ofmale wistar rats were randomized into two groups of three. The control group (n=3)was injected subcutaneously with normal saline solution (0.9% Na Cl)the treated group (n=3)was injected with CdCl2 solution at the concentration of 1.2 mg/kg BW subcutaneously for 5 days/weeks for 4 weeks (28 days,d1-d28;20 doses of DdCl2) the dose of CdCl2 and the period of treatment were modified from the study of prozialeck
Collection of rats urine and blood :A urinary sample was collected from each rat over 24hr using metabolic cage on day 0 and day 28 and a blood sample was collected by cardiac puncture on the last day of the experiment after the rats were anesthetized intraperitoneally with sodium phenobaraital solution. After perfusion of the whole animal physiological saline via the portal vein,the kidneys and livers were removed,washed with physiological salution and fixed in 10%
Neutral-buffered formalin for 48 hr for histopathological examination.
Determination of blood and urinary cadmium and creatinine :blood and urinary Cd concentrations were quantified by graphite furnace atomic absorption spectrometry (GFAAS)with Zeeman-GFAAS background correction (Varian,spectra A800Z)using 5%monobasic ammonium phosphate as a modifier. Blood samples were digested in 5%nitric acid solution with a ratio of 1:3 then mixed ,and centrifuged after standing for an hour.The supernatant was removed for analysis by GFAAS.Urine samples were diluted in 0.1%nitric acid solution with a ratio of 1:1 (v/v).Urinary crertinine levels were measured based on the Jaffe reaction.
Hisopathological study :the rat kidneys and livers were processed and individually embedded in the paraffin wax. Sections (5um) were cut and and stained with
Statistical analysis
All data were expressed as mean Standard error of mean (SEM) The statistical Significance was evaluated by one-way analysis Of variance (ANOVA) using SPSS version 12.0 Values were considered statistically significant When p< 0.05