LIST OF LETTERS, SYMBOLS HAVE ABBREVIATED
IN THESIS
TT Abbreviation All letters
1. ADN Acid desoxyribonucleic
2. ALA Acid aminolevulinic
3. ALAD Acid aminolevulinic dehydratase
4. ALT Alanin transaminase
5. AST Aspartat transaminase
6. GGT Gamma glutamyl transferase
7. GPx Glutathion peroxidase
8. GR Glutathion reductase
9. LO
•
Gốc alkoxyl
10. LOO
•
Gốc peroxyl
11. LPO Lipid hydroperoxides
12. MCH Mean corpuscular volume
13. MCHC Mean corpuscular hemoglobin concenrtration
14. MDA Malonyl dialdehyd
15. ppm Parts per million
16. G Group
17. ROS Reactive oxygen species
18. TAS Total antioxydant status
2
INTRODUCTION
When infiltrating into body, lead causes a number of
diversified and complicated injuries on most organs and
organizations. The mechanism of causing diseases of lead is
inhibiting and linking with enzymes, biological substances containing

causing to the body. From this fact, we conducted to study this theme.
3. New contributions of the thesis:
Lead is harmful to the body, causing oxidative stress which
leads to the alteration of antioxidant indexes. The thesis studied quite
comprehensively the antioxidant indexes of workers directly
exposing to inorganic lead and on experimental animals.
The thesis assessed the protective effects of Panax vietnamensis
biomass on animals semichronic poisoned with lead acetate.
By dint of the research results, factories, enterprises using
lead in production enhance measures to protect heath of labors as
well as study more to choose Panax vietnamensis biomass to protect
workers occupationally exposing to lead.
4. Arrangement of the thesis:
The thesis includes 137 pages consisting of 2 pages of
introduction, 38 pages of general view, 20 pages of research objects
and methods, 41 pages of research results, 33 pages of discussion, 2
pages of conclusion, 1 page of recommendation.
The thesis has 37 tables, 21 charts, 5 diagrams, and 161
references in which 27 in Vietnamese and 137 in English.
CHAPTER 1 - GENERAL VIEW
1.1. Free radicals and system against the free radicals of the body
1.1.1. Definition of free radicals and types of Reactive Oxygen
Species (ROS)
Free radicals are atoms or group of atoms whose outer layer
contains unpaired electrons (single electrons). Free radicals are
frequently unstable in both energy and kinematics and tend to reach
to very short stability and longevity, strong reactivity.
ROS are free radicals, active ions, and molecules containing
oxygen atoms and are capable of generating free radicals or activated
by free radicals.

antioxidant enzyme containing metal of oxidoreductase type and it
catalyzes the reaction to convert superoxid to O
2
and H
2
O
2
:
2
•
2
O
+ 2H
+

→
SOD
H
2
O
2
+ O
2
The higher activity SOD has, the less activity O
2
•
has. SOD SOD
is an very basic antioxidant that lowers the concentration of precursor
•
2

peroxidase
A + 2H
2
O
- Glutathion peroxidase (GPx) (E C.1.11.1.9) is an enzyme
catalyzing reactions to remove peroxides which activate in the tissues
and erythrocyte when the concentration of H2O2 is low.
GPx
ROOH + 2GSH GSSG + ROH + H
2
O
1.1.4.2. Non-enzymatic antioxidant system
It consists of three main groups: group of polyphenols, iron
and copper ligands and thiols. The gruops can exist both inside and
outside cells. This system support for te enzymatic antioxidant system.
- Total antioxidant status (TAS) is the total antioxidant status
of plasma basing on the ability of inhibiting and combating the oxidants of
antioxidants including all the antioxidants in the body wich include a lot of
protection systems to prevent from the adverse effects of free radicals and
peroxide phenomenon for the body.
1.2. The Mechanism of effect, capacity of generating free
radicals, inhibiting antioxidant system of inorganic lead
1.2.1. Mechanisms of common effects
Lead entering into the body will inhibit and connect
selectively with enzyme system, biomolecular having -SH group and
cause several important biochemical disorders of cells.
1.2.2. Mechanism of generating free radicals, inhibiting
antioxidant system of inorganic lead
Inorganic Lead induces to oxidative stress by two opposing
mechanisms closely linking to each other: stimulating the formation

2.1.1. Study labor environment
Study on characteristics of microclimate and lead level in the
air in labor environment.
2.1.2. Study on humans
- Objects: 165 workers working in primary detonating
explosives (Zx factory); battery assembly workshop, plate electrode
workshop (Vinh Phu Battery Joint Stock Company) directly exposing
to lead, are divided into 2 groups:
7
+ Group I (55 workers) has blood lead level ≤ 10 µg/dL
+ Group II (110 workers) has blood lead level > 10 µg/dL.
+ Group II is divided into 2 small groups: Group IIA (86
workers): blood lead level from 10 µg/dL to < 40 µg/dL and group IIB
(24 workers): blood lead level ≥ 40 µg/dL.
- Criteria to choose:
+ Time to work in the environment directly exposing to lead
is ≥ 5 năm, and continuous. Not expose to other toxic elements. And
participate in the study voluntarily.
+ Exclusion criteria: acute exacerbations of chronic diseases,
malignant diseases, diabetes mellitus, hypertension, kidney diseases,
acute and chronic hepatitis, liver failure and autoimmune disease.
- Choose all workers in the criteria and not in exclusion
criteria into the research.
2.1.3. Study on animals
* Experimental animals: 360 male white house-mice, 20 -
25 gram, divided into 3 lots.
- Control lot (108 mice) (lot 1).
- Lot infected lead acetate (108 mice) (lot 2).
- Lot infected lead acetate and drinking/with SNLSK to
protect (108 mice) (lot 3).

* Toxic method: Semichronic toxic method under toxic model
of El-Sayed I. H, Lotfy. M et al (2006); Flora G, Gupta D et al (2013)
- Lot 1 (n = 108): drink 0,2mL of distilled water in mornings
every day, continuous in 15 days, 30 days and 45 days.
- Lot 2 (n = 108): drink 0,2mL of lead acetate solution (20
mg/kg/day) in mornings every day, continuous in 15 days, 30 days
and 45 days.
- Lot 3 (n = 108): drink 0,1mL of Panax vietnamensis
biomass solution (375 mg/kg/day). After drinking SNLSK for one
hour, mice are drunk 0,2mL of lead acetate solution (20 mg/kg/day),
continuous in 15 days, 30 days and 45 days.
* Method of blood drawn for testing: Mice are killed at the
time of experiment and blood is taken at two eye sockets.
* Prior to the implementation of experiment: (36 mice).
- 12 mice are randomly selected, taken blood and divided
into 2 parts to test blood formula and blood lead level.
9
- 12 next mice are randomly in the remainder, taken blood
and divided into 2 parts to test the activity of SOD, erythrocyte GPx
and TAS, activity of peroxidase, plasma MDA, -SH.
- 12 remaining mice are taken blood to test biochemistry index.
* After the implementation of experiment: (324 mice).
- At the time of 15 days, 30 days and 45 days after the
implementation of experiment, 108 mice (each lot: 36 mice) are
randomly selected, killed and taken blood for the experiment.
* Research targets and techniques: as on humans.
2.3. Data processing
The data is processed by medical statistical methods and used
softwares such as EpiInfo 2005 (Version 3.3.2), EpiCalc 2000.
2.4. Ethnic issues in the research.

level
(µg/dL)
4,26±2,28 36,54±18,36 23,82±7,54 57,66±9,73
Blood lead level in group II, IIB have considerable change.
3.1.2.The result of test of SOD, GPx, peroxidase, -SH, MDA, TAS
in the research groups.
Table 3.7. The change of some antioxidant index in group I, II
Group
Content
Group I (n=55)
(
X
±SD)
Group II
(n=110)(
X
±SD)
p
SOD (U/g Hb) 1212.87±180.70 1578.26±180.65 p<0.001
GPx (U/g Hb) 64.46±8.57 54.29±7.82 p<0.001
Peroxidase (µg/mg) 0.019±0.006 0.021±0.008 p>0.05
- SH (mmol/mg) 0.685±0.092 0.461±0.120 p<0.001
MDA (µmol/L) 3.19±0.42 4.01±0.49 p<0.001
TAS (mmol/L) 1.58±0.22 1.42±0.21 p<0.001
Table 3.11. The correlation of SOD, GPx, peroxidase, MDA, TAS
with blood lead level in group II
Content r p Linear equation
SOD
(U/gHb)
BLL

Group
Content
Group I(n=55)
(
X
±SD)
Group II(n=110)
(
X
±SD)
p
RBC (T/L) 5.19±0.48 4.88±0.51 p<0.001
Hemoglobin
(g/L)
154.21±11.14 149.07±10.16 p<0.01
Hematocrid (%) 46.28±3,40 43.98±6,02 p<0.01
WBC (G/L) 7.10±1.36 7.18±1.49 p>0.05
PLT (G/L) 225.42±46,35 234.06±39.28 p>0.05
3.1.4. The result of test of biochemical blood indices in the research groups.
Table 3.15. The change of AST, ALT, GGT, total bilirubin
in plasma in group I, II.
Group
Content
Group I (n=55)
(
X
±SD)
Group II (n=110)
(
X

(mmol/L)
4.70±0.72 4.69±0.69 p>0.05
Triglycerid
(mmol/L)
1.68±0.64 1.72±0.71 p>0.05
3.2. Result of research on animals.
3.2.1. The mean blood lead level in experimental mice.
Table 3.21. Blood lead level (BLL) in the research lots (L)
L
BLL (µg/dL)
p
Date
o
(n=12)(a)
Date
15
(n=12)(b)
Date
30
(n=12)(c)
Date
45
(n=12)(d)
L 1
2.99±0.82 2.92±0.63 2.91±0.83 2.96±0.82
p
ba
>0.05
p
ca

p
32
<0.05
p
21
<0.05
p
32
<0.05
p
21
<0.05
p
32
<0.05
13
3.2.2. The result of a number of index of antioxidant in experimental
mice
Table 3.22. The change of activity of SOD of RBC at times
L
Activity of SOD (U/gHb)
p
D
o
(n=12)
(a)
D
15
(n=12)
(b)

L 3
1056.8±74.6 1138.3±45.0 1144.8±43.0 1138.4±40.7
p
ba
<0.05
p
ca
<0.05
p
da
<0.05
p
p
21
<0.05
p
32
<0.05
p
21
<0.05
p
32
<0.05
p
21
<0.05
p
32
<0.05

L 2 55.49±6.85 43.82±5.44 38.80±4.47 37.47±4.80
p
ba
<0.05
p
ca
<0.05
p
da
<0.05
L 3 55.49±6.85 50.14±4.01 49.92±2.99 50.07±3.72
p
ba
<0.05
p
ca
<0.05
p
da
<0.05
p
p
21
<0.05
p
32
<0.05
p
21
<0.05

L 1
0.062±0.005 0.063±0.005 0.062±0.006 0.064±0.004
p
ba
>0.05
p
ca
>0.05
p
da
>0.05
L 2
0.062±0.005 0.068±0.008 0.067±0.008 0.069±0.005
p
ba
<0.05
p
ca
>0.05
p
da
<0.05
L 3
0.062±0.005 0.063±0.004 0.063±0.006 0.065±0.005
p
ba
>0.05
p
ca
>0.05

D
15
(n=12)
(b)
D
30
(n=12)
(c)
D
45
(n=12)
(d)
L 1 1.89±0.06 1.88±0.05 1.89±0.03 1.90±0.0
7
p
ba
>0.05
p
ca
>0.05
p
da
>0.05
L 2 1.89±0.06 1.65±0.07 1.41±0.11 1.22±0.0
9
p
ba
<0.05
p
ca

p
32
<0.05
15
Table 3.26. The change of concentration of plasma MDA
at times
L
Concentration of MDA (µmol/L)
p
D
o
(n=12)
(a)
D
15
(n=12)
(b)
D
30
(n=12)
(c)
D
45
(n=12)
(d)
L 1 1.52±0.14 1.52±0.10 1.54±0.08 1.53±0.09
p
ba
>0.05
p

<0.05
p
21
<0.05
p
32
<0.05
p
21
<0.05
p
32
<0.05
Bảng 3.27. The change of concentration of plasma TAS at times
L
Concetration of TAS (mmol/L)
p
D
o
(n=12)
(a)
D
15
(n=12)
(b)
D
30
(n=12)
(c)
D

p
da
<0.05
p p
21
<0.05
p
32
<0.05
p
21
<0.05
p
32
<0.05
p
21
<0.05
p
32
<0.05
16
3.2.3. The result of test of peripheral blood formula in
experimental mice.
Table 3.28. The change of the number of RBC at times
L
Number of RBC (T/L)
p
D
o

<0.05
p
da
<0.05
L 3
7.81±0.34 7.28±0.38 7.31±0.35 7.30±0.29
p
ba
<0.05
p
ca
<0.05
p
da
<0.05
p
p
21
<0.05
p
32
<0.05
p
21
<0.05
p
32
<0.05
p
21

da
>0.05
L 2 90.5±4.2 80.4±3.9 77.7±3.8 75.6±4.5
p
ba
<0.05
p
ca
<0.05
p
da
<0.05
L 3 90.5±4.2 84.6±3.7 85.0±4.4 85.8±4.9
p
ba
<0.05
p
ca
<0.05
p
da
<0.05
p
p
21
<0.05
p
32
<0.05
p

L 1 38.3±5.6 39.2±5.1 37,9±5,4 40.0±4.4
p
ba
>0.05
p
ca
>0.05
p
da
>0.05
L 2 38.3±5.6 34.6±4.6 33,8±4,3 32.1±5.0
p
ba
>0.05
p
ca
<0.05
p
da
<0.05
L 3 38.3±5.6 37.7±3.9 37.4±4.1 36.6±4.7
p
ba
>0.05
p
ca
>0.05
p
da
>0.05

(n=12)(a) D
15
(n=12)
(b)
D
30
(n=12)
(c)
D
45
(n=12)
(d)
L 1
55.79±10.31 52.03±7.05 48.79±7.12 50.14±6.64
p
ba
>0.05
p
ca
>0.05
p
da
>0.05
L 2
55.79±10.31 59.14±13.77 61.42±11.71 66.14±10.85
p
ba
>0.05
p
ca

<0.05
p
32
<0.05
Table 3.32. The change of activity of AST in plasma at times
L
Activity of AST (U/L)
p
D
o
(n=12)
(a)
D
15
(n=12)
(b)
D
30
(n=12)
(c)
D
45
(n=12)
(d)
L 1
271.9±91.0 268.6±67.3 265.4±59.7 268.1±33.9
p
ba
>0.05
p

>0.05
p
32
>0.05
p
21
<0.05
p
32
>0.05
p
21
<0.05
p
32
<0.05
Table 3.33. The change of activity of GGT in plasma at times
19
L
Activity of GGT (U/L)
p
D
o
(n=12)
(a)
D
15
(n=12)
(b)
D

3.03±0.95 3.19±0.79 3.13±0.89 3.10±0.98
p
ba
>0.05
p
ca
>0.05
p
da
>0.05
p
p
21
<0.05
p
32
<0.05
p
21
<0.05
p
32
<0.05
p
21
<0.05
p
32
<0.05
CHAPTER 4 - DISCUSSION

reduced concentration of selenium in blood causing decreased activity
of GPx, or the increase of H
2
O
2
because when SOD activity increases
resulting in the increase of H
2
O
2
while H
2
O
2
inhibits GPx; besides lead
has effects on group SH of GPx causing enzyme inhibiton.
4.1.3. The effects of lead and peroxidase activity.
After SOD deoxidizes free radicals, generates a lot of H
2
O
2
,
peroxidase involves in the process of removing H
2
O
2
, peroxidase
uses H
2
O

blood lead level concentration led to decreased group SH and blood.
4.1.5. Effects of lead on the concentration of plasma MDA
For lead-exposing workers, the average concentration of
plasma MDA in group II increases compared to that in group I
(p<0.001) and that in group IIA, IIB increased compared to group I
(p<0.05). MDA positively correlates (r = 0.57, p <0.01) with blood
21
lead levels. For experimental animals, the average concentration of
MDA in Lot 2 increases compared to that in Lot 1 at the same time
and at the time before causing toxicity (p <0.05).
4.1.6. The effects of lead on the concentration of plasma TAS
For lead-exposing workers, the concentration of plasma TAS
in group II decreases compared to group I (p<0.001) and that in
group IIA, IIB decreases compared to group IIA and group IIB
(p<0.05), there is an inverse correlation between TAS and blood lead
levels (r = -0.32; p<0.05). For experimental animals, the average
concentration of TAS in Lot 2 decreases compared to the time before
causing toxicity and compared to Lot 1 at the same time (p<0.05).
4.2. The effects of lead on biochemical indices
4.2.1. The effects of lead on the concentration of urea, creatinine in
blood.
For lead-exposing workers, the average concentration of urea,
creatinine in blood in group II are higher than that in group I
(p<0.01), that in group IIB are higher than that in group I, IIA
(p<0.05); the concentration of urea, reatinin in blood positively
correlate with blood lead levels (r = 0.32, r = 0.38, p<0.5). For
experimental animals, in Lot 2 the average concentration of urea,
creatinine in blood increase compared with that in Lot 1 at the same
time of the study and compared with the time before causing toxicity
(p<0.05). Because lead is mainly eliminated out of the body through

) can be generated
less leading to lower activity of SOD. Kim. S. H et al (2003), a research
on volunteers showed that long-term use of ginseng may enhance the
effect of antioxidant potential of the body by improving the system of
antioxidants such as SOD, catalase . Nguyen Trong Diep et al (2012),
showed that Panax vietnamenis biomass has the effectiveness of
increasing SOD activity of radiation exposed rats and equivalent
effectiveness as Belaf.
* GPx activity of erythrocyte: average GPx activity of
erythrocyte in Lot 3 is higher than that in Lot 2 at the same time of the
study, but still lower than that in the initial time (p <0.05). Panax
vietnamenis biomass has the effectiveness of reducing blood lead levels
in Lot 3 compared to Lot 2. As a result, the activity of GPx in Lot 2 is
higher than that in Lot 3. Nguyen Trong Diep et al (2012) showed that
Panax vietnamenis biomass has the effectiveness of increasing GPx
activity of radiation exposed rats and equivalent effectiveness as Belaf.
Kilikdar D et al (2011) found that garlic is active in increasing the
activity of GSH, SOD in Lot causing lead poisoning compared to Lot
causing lead poisoning without using garlic
23
* The concentration of -SH group in blood: The concentration
of -SH group in blood in Lot 3 is higher than tht in Lot 2 at the same
time of study, but still lower than before causing toxicity (p <0.05) .
Panax vietnamenis biomass is active in reducing blood lead levels of
lead toxicity in which poisoning mechanism of lead has been widely
known as inhibiton of enzyme containing -SH group, so when blood
lead level increases resulting in the decreased concentration of -SH
group in blood. In Lot 2, blood lead levels decrease compared with Lot 3
leading to the higher concentration of -SH group.
* The concentration of plasma MDA: the concentration of

The average activity of ALT, AST, GGT in Lot 3 is lower
than that in Lot 2 (p <0.05). Nguyen Van Long (2011), the activity of
ALT, AST in lot of white house-mice poisoned by CCl
4
and drunk
Panax vietnamenis biomass (1.2 g/kg) reduced compared with
poisoned Lot without using Panax vietnamenis biomass (p <0.01),
the weight of liver increased less (p <0.05) and the histopathological
images showed that damage of liver is milder, the number of liver
necrosis in rats is less. Nguyen Thi Thu Huong et al (2006), Tran Q.
L et al (2001), Panax vietnamenis biomass has the effectiveness of
protecting liver cells when causing damages to experimental liver.
CONCLUSION
1. The changes of some antioxidant indexes and serum
biochemistry in people occupationally exposed to inorganic lead
and experimental animals.
1.1. In workers occupationally exposed to inorganic lead.
- Reduce the activity of antioxidant enzymes such as
erythrocyte GPx, -SH group, plasma total antioxidant status (TAS) in
blood lead level > 10 µg/dL (group II) compared to blood lead level
≤ 10 µg/dL (group I) (p<0.001). GPx, -SH and TAS have inverse
correlation with blood lead level (r = -0.49; r = -0.68 and r = -0.32).
Increase the activity of antioxidant enzymes, erythrocyte SOD, plasma
MDA level in group II compared to group I (p<0.001). SOD, MDA have
positive correlation with blood lead level (r = 0.45; r = 0.57).
- Increase the activity of enzymes such as AST, ALT, GGT,
urea level and creatinine in group II compared to group I (p<0.05 and
p<0.01). Activity of GGT, urea and creatinine level have positive
correlation with blood lead level (r = 0.31; r = 0.32 và r = 0.38).
25