Effect of mercuric chloride on various hydroxyproline fractions in rat serum

Mercuric chloride (HgCl2) disturbs the collagen metabolism in the body which is reflected by altered hydroxyproline fractions in the serum. The aim of the present investigation was to study the effect of HgCl2 treatment on various hydroxyproline (Hyp) fractions in rat serum and the effect of 2,3-dimercapto-1-propane sulfonic acid (DMPS) treatment on serum Hyp fractions in HgCl2 treated rats. Other parameters studied included body weight, food intake, water intake and kidney weight. Doses of HgCl2 used were 0.1, 0.5, 1.0, 2.0, 3.0 mg/kg body weight and that of DMPS was 100 mg DMPS/kg body weight. All the doses of HgCl2 used caused significant (p < 0.01) alterations in free, peptide-bound and protein-bound Hyp in the serum when compared with control rats but a dose of 2 mg/kg body weight caused significant (p < 0.001) alteration even in the total serum Hyp when compared to control rats. Administration of DMPS prior HgCl2 treatment of rats sacrificed 24 h after the treatment caused a significant decrease of 52% (p < 0.01) in free Hyp when compared to similar HgCl2 treated rats. DMPS treatment with HgCl2 also caused an increase of 61% (p < 0.001) and 114% (p < 0.001) in peptide- and protein-bound Hyp respectively, when compared to HgCl2 treated rats sacrificed 24 h after mercuric chloride and DMPS treatment. Administration of DMPS followed by HgCl2 to rats which were sacrificed 48 h later caused no significant change in the total and free Hyp when compared to HgCl2 treated rats which were sacrificed 48 h after the treatment. But there was a significant decrease of 40% (p < 0.001) in peptide-bound Hyp and an increase in of 77% (p < 0.001) in protein-bound Hyp when compared to HgCl2 treated rats sacrificed 48 h after the treatment. The present study shows that HgCl2 treatment caused significant alterations in serum Hyp fractions reflecting disturbed composition of connective tissues which were not reversed by DMPS treatment.