Mercury retention after Panax ginseng treatment against mercuric chloride intoxication in hepato-haemato indices in albino rats

Mercuric chloride was introduced per Os in albino rats ( Rattus norvegicus ) as per the LD 50 (9.26 mg/kg b.w.). The assessment of mercuric chloride toxicity was done both after acute (0.926 mg/kg b.w.) and sub-acute (0.033 mg/kg b.w.) per Os treatment, while Panax ginseng was also introduced (10 mg/kg b.w.) per Os in the albino rats separately. Mercuric chloride treatment significantly increases mercury retention in liver and blood serum along with increase in liver weight, while Panax ginseng alone caused significant decrease in liver weight and mercury retention in liver and blood. Increase in mercury retention in blood serum and liver is due to the reactivity between –SH protein of blood serum and liver with oxidized form of mercury (Hg ++ ), while decrease in Panax ginseng treatment is due to antioxidant activity of Panax ginseng the ginsenosides. Moreover, mercuric chloride followed by Panax ginseng and Panax ginseng followed by mercuric chloride treatment revealed significant modulation for raised mercury retention and liver weight towards normal level along with blood serum and liver changes. The results suggest a modulating role of Panax ginseng extract against raised mercury concentration in blood serum and liver under stress of mercuric chloride.


Introduction
The liver and blood are the two important vital organs for assessing effects of xenobiotic substances.Mercuric chloride, widely used in industrial purposes, poses a threat to the mankind an account of its level which gets in the environment exceeded as mercury is such a heavy metal which has been found to be injurious in all three forms, elemental, inorganic and organic.
Many metabolic disorders in man are accompanied by alterations in the concentration of one or more trace elements in some body fluid, especially blood serum or plasma [1].
Mercuric chloride is an inorganic compound that has been used in agriculture as fungicides, in medicine as tropical antiseptic and disinfectant and in chemistry as an intermediary in the production of other mercury compounds.Industrial use of mercury and its toxic effects on human as well as animal systems are well documented [2], Neurotoxic, nephrotoxic and reproductive effects of mercury are known since long time and documented clinically and experimentally [3][4][5][6][7].
Hence, this study was undertaken to evaluate mercury concentration in liver and blood serum with mitigate role of Panax ginseng against mercuric chloride intoxication in albino rat.

Collection of extract
The plant root powder was gifted by Prof. A. Kumar, Cancer & Radiation Biology Laboratory, department Of Zoology, Rajasthan University, Jaipur (Rajasthan).

Experimental animals
Rattus norvegicus weighing approximately (120-130) gm of both the sexes were procured from inbreed colony.The rearing of animals as well as experiment was approved by the ethics committee of department of Zoology, Dr. B. R. A. University, Agra (U.P.) India.The animals were fed with a standard balanced diet and water was provided ad libitum.

Experimental compound
Experimental compound (mercuric chloride) was obtained from Bayer India Ltd.Bombay while other chemicals were procured from Sigma chemical, Germany and SRL, Mumbai.

Experiment group
The acute oral LD50 was determined on albino rats.The data were analyzed by probit analysis for LD50 determination (Table -1).

Estimation of mercury level
The rats were sacrificed and liver was excised out immediately.Mercury levels were estimated by acid digestion method [8].A known amount of tissue was weighted and digested in a mixture of perchloric acid, conc.nitric acid and sulphuric acid.The digested sample was cooled, transferred to volumetric flask and diluted to a required volume.Digested sample was analyzed by making use of the cold vapour atomic absorption spectrometry technique, while blood serum mercury concentration was estimated from 20 time's diluted serum with AAS.Body and liver weight were also recorded.
Statistically significant values between experimental and control values were calculated according to Fisher's student's' test [9,10].

LD50
LD50 of mercuric chloride calculated in the present investigation has been 9.26 mg/kg b.w. and is in accordance to Mark et al. [11] who observed LD50 as 8.26 mg/kg b. w. against mice.

Hepatic weight
Liver weight were significantly (p<0.001)increased in acute and sub-acute mercuric chloride treated groups with respect to 100 gms of body weight.It was significantly (p<0.01)decreased in Panax ginseng treated groups.It was increased non-significantly in mercuric chloride followed by Panax ginseng treated sets, decreased non-significantly in Panax ginseng followed by mercuric chloride treated set.(Table -2) Increased liver weight in mercuric chloride treated groups may be due to hepatic fibrogenesis, it was decreased in Panax ginseng treated group probably due to their antioxidant potential.In mercuric chloride followed by Panax ginseng and Panax ginseng followed by mercuric chloride sets, liver weight was decreased in comparison to the mercuric chloride treated set may probably be due to release of free radicals of mercuric chloride.These free radicals behave like electron accepter (lone pair of electron).

Hepatic mercury concentration
Mercury concentration in liver were significantly increased in acute and sub-acute mercuric chloride treated groups with respect to control, it was decrease none significantly in Panax ginseng treated groups.It was decreased in mercuric chloride followed by Panax ginseng sets; significantly decrease in Panax ginseng followed by mercuric chloride treated sets (Table -3).
Increased mercury concentration in liver in mercuric chloride treated set is due to binding capacity of mercury with -SH groups of protein [3,5,6,12].It was decreased in Panax ginseng treated group probably due to their antioxidant potential [7,13].In mercuric chloride followed by Panax ginseng and Panax ginseng followed by mercuric chloride sets, mercury concentration was decreased significant in Panax ginseng followed by mercuric chloride treated set should be due to release of Hg ++ of mercuric chloride.These Hg ++ bind with free radicals of Panax ginseng (electron accepter) and minimized mercury toxicity [7].

Blood serum mercury concentration
Mercury concentration in blood serum was also increased significantly in acute and sub-acute mercuric chloride treated groups with respect to control.It was decrease significantly in Panax ginseng treated groups.It was decrease nonsignificant in mercuric chloride followed by Panax ginseng sets however, significant decreased in Panax ginseng followed by mercuric chloride set (Table -4).
Increased mercury concentration in serum in mercuric chloride treated set is due to readily binding capacity to RBCs of blood [5,6,14,15,16], while in all others groups it should be vide supra.

Conclusion
Comparing all data of liver weight, mercury concentration in liver and blood serum suggested that concentration of mercury minimized by Panax ginseng in all respective sets expect mercuric chloride treated set.Hence Panax ginseng is having modulating effect in liver and blood serum against mercuric chloride intoxication in albino rats.

Table 1
Toxicity evaluation of Mercuric Chloride in albino rat, Rattus norvegicus Specifying

fiducial limits Experimental individual Compound Regression equation LD50 (mg/kgb.w.) Variance Fiducial limits
Animals were divided into 5 groups of 5 rats each.Group I received 1 ml of distilled water and 10 µl tween-20, group II received Panax ginseng (10 mg/kg b. wt), group III received mercuric chloride after LD50 (9.26 mg/kg b. wt.) determination for acute (0.926 mg/kg b. wt.) and sub-acute (0.330 mg/kg b. wt.) sets, group IV received Panax ginseng followed by mercuric chloride while, group V received mercuric chloride followed by Panax ginseng (Table-2, 3 and 4).

Table 2
liver weights in gms/100 gm of body weight (Gms) after successive treatment of various substances

Table 3
Mercury levels (ng/mg tissue) in liver of Rattus norvegicus after acute and sub-acute treatment

Table 4
Mercury levels (pg/ml) in blood serum of Rattus norvegicus after acute and sub-acute treatment