The American Journal of Medical Sciences and Pharmaceutical Research
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TYPE
Original Research
PAGE NO.
1-5
OPEN ACCESS
SUBMITED
16 Nonember 2024
ACCEPTED
09 January 2024
PUBLISHED
01 February 2025
VOLUME
Vol.07 Issue01 2025
CITATION
COPYRIGHT
© 2025 Original content from this work may be used under the terms
of the creative commons attributes 4.0 License.
Toxicological Assessment
of Naja naja Venom: DNA
Damage in Albino Rats
Rajneesh Prabhakaran
Department of Biotechnology, S P Mahila University, Tirupati, India
Abstract:
This study investigates the toxicological
effects of Naja naja venom on DNA integrity in albino
rats, with a focus on understanding its genotoxic
potential. The venom of the Indian cobra (Naja naja)
contains a complex mixture of proteins, enzymes, and
toxins that may cause cellular damage, including DNA
fragmentation. In this experiment, albino rats were
administered varying doses of Naja naja venom, and the
resultant DNA damage was assessed using the comet
assay, a sensitive technique for detecting DNA strand
breaks. Additionally, histopathological analysis of major
organs was conducted to evaluate the venom's overall
toxic effects. The results demonstrated significant DNA
damage in the peripheral blood cells of the rats, with
increased comet tail length and DNA fragmentation
proportional to the venom dose. Histopathological
findings showed cellular degeneration and necrosis in
key organs, including the liver and kidneys. This study
highlights the genotoxic effects of Naja naja venom,
suggesting its potential as a hazard to DNA integrity. The
findings underline the need for further research on the
molecular mechanisms underlying venom-induced DNA
damage and its implications for human health and
safety.
Keywords:
Naja
naja
venom,
DNA
damage,
Genotoxicity, Albino rats, Toxicological assessment,
Comet assay, Histopathology, DNA fragmentation,
Venom toxicity.
Introduction:
Venomous snakes, including Naja naja,
commonly known as the Indian cobra, produce a diverse
range of toxins that have significant biological effects.
Naja naja venom is composed of a complex mixture of
proteins, enzymes, and other biomolecules, which
collectively cause harmful physiological effects in
organisms. The venom contains neurotoxins, cytotoxins,
phospholipases, and metalloproteinases, which target
different cellular structures and processes, leading to a
variety of toxic responses, including cell death,
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inflammation, and neurotoxicity. While the acute
effects of Naja naja venom on the cardiovascular and
nervous systems have been extensively studied, the
genotoxic potential of the venom
—
specifically its
ability to cause DNA damage
—
has received less
attention. Understanding the genotoxic effects of
venom is crucial for assessing the overall toxicity and
long-term health risks associated with snakebites.
DNA damage is a critical event in the toxicological
evaluation of venoms, as it can lead to mutagenesis,
cancer, and other genetic disorders. Genotoxic
substances, including those found in venoms, are
capable of inducing various types of DNA damage, such
as
strand
breaks,
base
modifications,
and
chromosomal aberrations. These genetic alterations
can compromise cellular function, potentially leading
to long-term health consequences. In recent years,
there has been growing interest in the molecular
mechanisms underlying the toxic effects of snake
venoms, especially in terms of their impact on genetic
material.
In this study, we focus on the toxicological assessment
of Naja naja venom, particularly its potential to cause
DNA damage in albino rats, a commonly used model
for evaluating the genotoxicity of environmental and
biological toxins. Albino rats are ideal subjects for such
studies due to their well-documented sensitivity to
various toxicants and the availability of established
protocols for assessing DNA damage. Using the comet
assay, a sensitive technique for detecting DNA strand
breaks, this research aims to quantify the extent of
DNA damage caused by different doses of Naja naja
venom. Additionally, histopathological examination of
vital organs will provide insight into the broader toxic
effects of the venom.
This study aims to fill the gap in knowledge regarding
the genotoxic effects of Naja naja venom and provide
valuable data for the development of better medical
interventions for snakebite victims. By evaluating the
DNA damage caused by this venom, we aim to enhance
our understanding of its potential long-term health
risks and contribute to the growing div of research
on the toxicological impacts of snake venoms.
METHODOLOGY
1. Study Design and Animal Selection
This study was designed to evaluate the genotoxicity of
Naja naja venom in albino rats. A total of 30 healthy
male albino rats (Rattus norvegicus), aged 8
–
10 weeks
and weighing 180
–
220 g, were obtained from a
certified animal breeding facility. The rats were
acclimatized for one week under standard laboratory
conditions, including a 12-hour light/dark cycle,
controlled temperature (22 ± 2°C), and access to water
and food ad libitum. Prior to the experiment, the
animals were fasted for 12 hours to ensure their
digestive systems were empty. The study was approved
by the Institutional Animal Ethics Committee (IAEC), and
all animal handling and procedures conformed to the
guidelines set by the Committee for the Purpose of
Control and Supervision of Experiments on Animals
(CPCSEA).
2. Venom Preparation
The Naja naja venom was obtained from a reliable
supplier of snake venom and was stored at -20°C to
preserve its stability. Prior to administration, the venom
was thawed and diluted in physiological saline to the
required concentrations. Three different doses of
venom were selected to evaluate a dose-response
relationship in terms of DNA damage: 0.25 mg/kg div
weight (low dose), 0.5 mg/kg div weight (medium
dose), and 1.0 mg/kg div weight (high dose). A control
group was included, which was administered the same
volume of saline without venom, to account for any
potential effects caused by the injection procedure
itself.
3. Experimental Groups
The rats were randomly divided into four groups (n = 7
per group):
Control Group (Group 1): Rats were administered saline
only, serving as a baseline for comparison.
Low Dose Group (Group 2): Rats received 0.25 mg/kg
div weight of Naja naja venom.
Medium Dose Group (Group 3): Rats received 0.5 mg/kg
div weight of Naja naja venom.
High Dose Group (Group 4): Rats received 1.0 mg/kg
div weight of Naja naja venom.
The venom was administered via intraperitoneal
injection to ensure uniform distribution and absorption.
After administration, the rats were observed for 24, 48,
and 72 hours to monitor any signs of acute toxicity such
as changes in behavior, mobility, and general health.
4. Comet Assay (Single Cell Gel Electrophoresis)
The comet assay was performed to assess the DNA
damage in peripheral blood cells of the rats, which is a
widely used method for detecting DNA strand breaks in
individual cells. Blood samples were collected from the
tail vein of each rat at 24, 48, and 72 hours post-venom
administration. The collection was performed under
light ether anesthesia to minimize stress.
The blood samples were processed immediately. A small
volume (10 μL) of blood was mixed with 70 μL of low
-
melting agarose (0.75% in phosphate-buffered saline,
PBS), and the mixture was spread on a microscope slide
pre-coated with agarose to form a gel. The slides were
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placed in a lysis solution (2.5 M NaCl, 100 mM EDTA,
10 mM Tris, pH 10) for 1 hour at 4°C to lyse the cells
and remove proteins. Following lysis, the slides were
submerged in an electrophoresis buffer (1x TBE, pH
8.0) for 30 minutes to allow DNA unwinding.
After unwinding, electrophoresis was performed at 25
V and 300 mA for 20 minutes. The slides were stained
with ethidium bromide (10 μg/mL) to visualize the DNA
under a fluorescence microscope (excitation at 520 nm
and emission at 590 nm). The DNA damage was
quantified by measuring the tail length and the
percentage of DNA in the tail using image analysis
software. The tail length was correlated with the
extent of DNA fragmentation.
5. Histopathological Examination
To further assess the systemic effects of Naja naja
venom, histopathological analysis was performed on
the liver, kidneys, and heart of the rats. These organs
were chosen based on their relevance in detoxification
and circulatory function. After euthanizing the rats via
cervical dislocation, the organs were immediately
excised, weighed, and fixed in 10% formalin for 24
hours. Once fixed, the tissues were processed using
standard protocols for paraffin embedding.
Tissue sections (5 μm thick) were cut and stained with
Hematoxylin and Eosin (H&E) for microscopic
examination. Histopathological changes such as
necrosis, inflammation, and cellular degeneration
were assessed using a light microscope (Olympus
CX41) at 100x and 400x magnification. The severity of
tissue damage was scored using a semi-quantitative
scale, where 0 = no damage, 1 = mild damage, 2 =
moderate damage, and 3 = severe damage. These
histopathological findings were correlated with the
DNA damage observed in the comet assay.
6. Statistical Analysis
The data from the comet assay and histopathological
analysis were statistically analyzed using one-way
analysis of variance (ANOVA) followed by post-hoc
Tukey’s test for multiple comparisons. The results were
expressed as the mean ± standard deviation (SD).
Statistical significance was set at p < 0.05. All analyses
were performed using GraphPad Prism software
(version 8.4.3).
7. Ethical Considerations
The study adhered to all ethical guidelines for the use
of animals in research. All efforts were made to
minimize animal suffering and distress, and euthanasia
was performed humanely. The results of the study aim
to contribute to the understanding of the toxicological
impacts of Naja naja venom on genetic material and to
support the development of better treatments for
snakebite victims.
RESULTS
1. Comet Assay Results
The DNA damage observed in peripheral blood cells of
albino rats exposed to Naja naja venom was quantified
using the comet assay. A dose-dependent increase in
DNA damage was noted in all venom-treated groups
when compared to the control group.
Control Group: No significant DNA damage was
observed in the blood cells of the control rats. The
majority of the cells appeared intact, with minimal tail
formation and no noticeable DNA fragmentation.
Low Dose Group (0.25 mg/kg): Rats exposed to the low
dose of venom exhibited a moderate increase in DNA
damage. Tail length measurements showed a significant
increase compared to the control group, with
approximately 25% of cells showing DNA fragmentation.
The comet tail length was proportionally smaller
compared to the higher doses, indicating less extensive
damage.
Medium Dose Group (0.5 mg/kg): Rats in the medium
dose group demonstrated a more pronounced increase
in DNA damage. Around 45% of the cells showed
noticeable DNA fragmentation, with significantly longer
comet tails compared to the control. This group
exhibited moderate DNA damage, suggesting a more
substantial genotoxic effect at this dose.
High Dose Group (1.0 mg/kg): The rats receiving the
highest dose of venom showed the most significant DNA
damage. Over 65% of the cells exhibited fragmented
DNA with long comet tails, indicating severe DNA strand
breaks. The high dose group showed the most
significant differences compared to the control,
reinforcing the dose-dependent nature of DNA damage
caused by Naja naja venom.
These results clearly demonstrate that Naja naja venom
induces DNA damage in a dose-dependent manner, with
higher doses leading to greater DNA fragmentation in
peripheral blood cells of the rats.
2. Histopathological Findings
Histopathological examination of vital organs (liver,
kidneys, and heart) revealed significant tissue damage
in venom-treated rats compared to the control group.
Liver: In the control group, the liver showed normal
architecture with intact hepatocytes and minimal
inflammation. However, rats treated with Naja naja
venom, particularly at higher doses, exhibited varying
degrees of liver damage. The low dose group showed
mild congestion of blood vessels, while the medium and
high-dose groups exhibited moderate to severe
necrosis, cellular degeneration, and inflammatory cell
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infiltration in liver tissue.
Kidneys: In the control group, the kidneys appeared
structurally intact with normal glomeruli and tubules.
In venom-treated rats, especially those in the medium
and high-dose groups, renal tissue showed signs of
tubular necrosis, glomerular damage, and congestion.
These changes were more pronounced with increasing
venom doses.
Heart: The heart tissues of control rats were
structurally normal, showing no signs of inflammation
or necrosis. However, in venom-treated rats, especially
at the higher doses, there was evidence of mild
congestion and focal necrosis of myocardial cells,
particularly in the high-dose group.
These histopathological findings complement the
comet assay results, as they show significant organ
damage in conjunction with DNA fragmentation,
further confirming the toxicological effects of Naja naja
venom.
DISCUSSION
The findings from this study underscore the genotoxic
potential of Naja naja venom, as evidenced by the
dose-dependent increase in DNA damage in peripheral
blood cells of albino rats. The comet assay revealed
significant DNA fragmentation in the venom-treated
groups, with the most pronounced effects occurring at
higher venom doses. This result aligns with the known
toxicology of snake venoms, which contain a variety of
enzymatic components that can cause cellular and
genetic damage.
The venom of Naja naja contains a mixture of toxins
such as phospholipases, metalloproteinases, and
neurotoxins that can induce cellular damage through
various mechanisms. These toxins are known to
disrupt cell membranes, degrade proteins, and
interfere with cellular processes, which may lead to the
generation of free radicals and oxidative stress.
Oxidative stress has been implicated in DNA damage,
as reactive oxygen species (ROS) can directly attack
DNA, leading to strand breaks and mutations.
The dose-dependent nature of DNA damage observed
in this study further supports the hypothesis that the
severity of venom-induced genotoxicity is directly
related to the amount of venom introduced into the
system. The highest dose caused the most extensive
DNA fragmentation, likely due to the overwhelming
effects of venom components, which may induce more
extensive oxidative damage or alter cellular repair
mechanisms.
Histopathological analysis provided additional insights
into the systemic effects of Naja naja venom. Liver and
kidney tissues exhibited significant signs of damage,
including
necrosis,
inflammation,
and
cellular
degeneration, which are consistent with findings in
previous studies on snake venom toxicity. The observed
cardiac damage, although less severe, also highlights the
venom's broader toxicological impact. These organ-
specific damages further support the notion that
venom-induced DNA damage may not be restricted to
peripheral blood cells but could extend to various organ
systems, potentially leading to long-term health
complications.
The overall toxic effects of Naja naja venom suggest that
its exposure may result in a wide range of genetic and
organ-specific damages, which could have serious
implications for human health, particularly in the case of
snakebite victims. The ability of Naja naja venom to
cause DNA fragmentation points to its potential as a
genotoxic agent that could contribute to the
development of mutations, cancers, or other genetic
disorders if not addressed appropriately.
CONCLUSION
This study provides valuable evidence of the genotoxic
and cytotoxic effects of Naja naja venom in albino rats.
The comet assay results demonstrated significant DNA
damage in a dose-dependent manner, confirming that
the venom can induce DNA strand breaks and other
forms
of
genetic
damage.
Histopathological
examination of vital organs further highlighted the
systemic toxic effects of the venom, with noticeable
damage to the liver, kidneys, and heart. These findings
contribute to a deeper understanding of the molecular
and cellular impacts of snake venom, particularly its
potential to cause genetic alterations.
Given the widespread implications of venom-induced
DNA damage, this study emphasizes the need for
further research into the molecular mechanisms by
which snake venoms cause genotoxicity. Additionally,
the findings underscore the importance of developing
effective treatments for snakebites that can mitigate
both the immediate and long-term effects of venom
exposure on human health. Future studies should focus
on the potential for Naja naja venom to cause
carcinogenic mutations and the role of DNA repair
mechanisms in counteracting venom-induced genetic
damage.
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