Histological and Physiological Study of the Effects of Exogenous Melatonin on Liver of Female Rats Exposed to Formalin in Drinking Water

Abstract

Aim: The presented study was established to evaluate the impact of formalin (FA) on the blood levels of
superoxide dismutase (SOD), lipid profile, total serum protein and serum albumin in female rats. Materials
and methods: The animals were assigned randomly into groups of six; control group, and treated other five
groups as follow, first group exposed to formalin at 200ppm (F200 group), the second exposed to formalin
at 400ppm (F400 group), third group exposed to formalin at 200ppm plus melatonin at 10mg/kg (F200M
group), fourth group exposed to formalin at 400ppm plus melatonin at 10mg/kg (F400M group), and the
fifth exposed to melatonin at 10mg/kg (M group). Samples of blood from the rats were collected at day one,
day and day 30 of the experimental period that was continued for 30 days. Results: Using immune-based
techniques, the SOD activity, it has been here-resulted in significant (p?0.05) after-formalin-exposuredecreases in the blood samples of female rats from F200 and F400 groups, especially, when compared
with the control group. The total cholesterol levels revealed significant (p?0.05) increases in the blood of
the tested animals of the F200 and F400 groups. These increases affected the rates of LDL, VLDL, and
triglycerides in the blood of the studied rat-females of both F200 and F400 groups when compared with
the control animals. Interestingly, low levels of HDL were noticed in the blood of the animals of the F200
and F400 when comparisons with control animals. The concentrations of the LDL, HDL, and triglycerides
in the serum of the formalin-exposed females showed significant (p?0.05) low levels when compared with
control animals. For day-30 collection, albumin concentrations revealed significant (p?0.05) elevation in the
blood of the F200 and F400 animals.. Histological examination revealed that the liver of female rats exposed
to 200ppm or 400 ppm of formalin for 30 days have been adversely affected. Whereas, the histological
examination of the liver of animals treated with melatonin and formalin were less affected due to formalin
exposure. Conclusions: These results demonstrate the formalin high toxic effects on the hepatic tissues can
be overcome by the use of exogenous melatonin.