Potential effects of ultraviolet-C radiation on the mole rats (<i>Spalax leucodon</i>) hematological values

doi:10.4236/ajmb.2013.34030

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American Journal of Molecular Biology, 2013, 3, 235-240 AJMB

http://dx.doi.org/10.4236/ajmb.2013.34030 Published Online October 2013 (http://www.scirp.org/journal/ajmb/)

Potential effects of ultraviolet-C radiation on the mole rats

(Spalax leucodon) hematological values

Huseyin Turker

Department of Biological Science, Ankara University, Ankara, Turkey

Email: [email protected]

Received 27 August 2013; revised 25 September 2013; accepted 7 October 2013

permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

ABSTRACT UV beams are known to enable photosynthesis in

plants and vitamin D synthesis in human, kill pathogen

microorganisms and provide heat for the survival of life.

On the other hand, solar dermatitis, sun burn, pigmenta-

tion, cataract and skin cancer formation, acne, echymosis,

keratosis, photodermatosis, light sensitivity, mutation,

actinic elastosis and sensitivity to infections due to im-

mune deficiency may be seen due to over exposure to

UV beams [1,2,6,7]

In this study, the effect of ultraviolet-C (UVC) radia-

tion on hematologic parameters of mole rats (Spalax

leucodon) was studied. Ten mole rats of both sexes,

weighing 150 - 200 g, were used. The rats were ex-

posed to 8 hours daily UVC radiation for 45 days.

Before the radiation exposure (as a control) and on

day 7, 14, 30 and 45, blood specimens were obtained

from the experimental groups. Then blood samples

were analyzed and compared to the control groups. A

significant decrease or increase of hematological pa-

rameters was observed in some experimental groups

in terms of the control groups of values (p < 0.05).

Alterations in other hematological parameters were

not found to be statistically significant (p > 0.05).

These results showed that the UVC radiation has sig-

nificant effects on some hematological parameters of

mole rats according to the radiation exposure time

and a dose.

Keywords: Ultraviolet Radiation; Mole Rats (Spalax

leucodon); Hematological Parameters

1. INTRODUCTION

To our knowledge, plenty of data have been gathered

concerning the effects of UVA and UVB radiations on

biochemical, hematological or histopathological charac-

teristics of animals [8-18], but similar studies done with

UVC radiation on the hematological cells on Mole rats

(Spalax leucodo n) have not been encountered.

For this reason, the mole rats were selected as they

lived in the underground galleries, and had no UV expo-

sure in their habitat. Therefore, they were exposed to an

artificially produced UVC radiation in the lab, and the

hematological changes were compared with the control

group.

2. MATERIALS AND METHODS

Ten adult mole rats of both sexes (Spalax leucodon),

weighing 150 - 200 g were used in this study. All animals

were caught in the rural areas of Ankara, Turkey. All rats

were kept at the laboratory for 10 days at a stable tem-

perature (20 ± 2 degrees centigrade) in order to ensure

adaptation of the animals to their new environment. And

then they were placed in special cages called terrarium

(Figure 1).

Sunlight exposure harms biologic systems via ultraviolet

(UV) radiation due to its short wave length and high en-

ergy. The wave length of UV beams was emitted by sun

changes between 200 - 400 nm. UV beams are classified

according to their wavelength; UVA (320-400) UVB

(280-320) and UVC (200-280) [1,2].

All rats were placed to terrarium separately and a con-

stant UVC dosage was applied. All animals were fed

with carrot, potato and plant roots, and no special diet

was given.

UVC radiation is especially important in terms of its

harmful effects on the living beings. Fortunately, the

majority of this radiation is filtered by the ozone (O3)

layer. As the thickness of this layer has reduced in recent

years, it is estimated that skin cancer, cataract and im-

mune deficiency syndrome cases will increase in the near

future [3-5].

A “Mazda TG” ultraviolet lamp in 30 W powers and in

90 cm length was placed to the upper cover of the terrar-

ium. The intensity of the UV emitted from the lamp was

OPEN ACCESS

H. Turker / American Journal of Molecular Biology 3 (2013) 235-240

236

Figure 1. The terrarium where the rats were ex-

posed to UVC radiation.

measured to be 254 nm in wavelength and the energy in

one second was found to be 0.0014 joule/cm2. Sunlight

period was taken into account and rats were exposed to

UVC for 8 hours per day (between 08:00 - 17:00 hours)

during 45 days. A feeding interval was given at midday

for 1 hour. A timer was used to control the UVC expo-

sure times.

Blood specimens of 2 cc were obtained to 1 ml EDTA

tubes from the intra cardiac route under light ether anes-

thesia, before UVC exposure (at day 0) and on days 7, 14,

30 and 45. After waiting for 10 minutes at a room tem-

perature, samples were centrifugated at 2500 rpm for 10

minutes. The plasma was separated and put into different

tubes and analysis was performed. Erythrocyte, leuko-

cyte, hemotocyrite, neutrophil, lymphocyte monocyte,

eosinophil, basophile and hemoglobin values were meas-

ured with Contraves Digicel 3100-H.

Data were analyzed using the SPSS for Windows soft-

ware, Version 18.00(SPSS Inc., Chicago, IL, USA). The

differences between means of the control and experi-

mental groups were evaluated by Wilcoxon Signed

Ranks Test. “Two-Related Samples Tests” was applied

for further analysis. At the end of the study, all rats were

taken to the areas they had been caught.

The experiment was carried out in accordance with the

Ankara University guidelines for the care of the experi-

mental animals. Besides, guiding principles for experi-

mental procedures presented in the World Medical Asso-

ciation’s Declaration of Helsinki, regarding animal ex-

perimentation were followed in the study.

3. RESULTS

Blood parameters of the UVC exposed rats were pre-

sented in Table 1. Statistically significant changes in

some blood parameters were documented after 45 days.

Erythrocyte counts on day 14, 30 and 45, hemoglobin

value on day 45, leukocyte counts on day 30 and 45,

neutrophil values on day 7, 14 and 30, monocyte value

on day 30 were found statistically significant (p < 0.05)

compared to day 0 (control) values whereas hematocryte,

lymphocyte, eosinophil and basophile values were found

statistically insignificant (p > 0.05).

Ta ble 1. The hematological findings from control and exposed

animals (Mole rats) to UVC radiation according to exposure

time (7, 14, 30 and 45 days).

Radiation Period (Days)

Variables 0 d

(n = 10)7

(n = 10) 14

(n = 10) 30

(n = 10)45

(n = 10)

Erythrocyte

(106/mm3)

8.57 ±

0.95

8.76 ±

1.42

7.53 ±

1.00a

7.65 ±

1.40a

9.65 ±

0.89b

Hemoglobin

(g/dl)

12.46 ±

1.27

11.58 ±

1.17

12.56 ±

1.30

13.22 ±

0.83

13.60 ±

0.81b

Hematocryte

(%)

46.20 ±

4.54

44.50 ±

3.80

46.80 ±

4.70

48.20 ±

5.11

50.40 ±

4.92

Leukocyte

(103/mm)

29.90 ±

13.85

36.50 ±

18.75

41.00 ±

19.14

45.40 ±

19.31a

54.40 ±

17.43a

Lymphocyte

(%)

29.30 ±

6.42

33.80 ±

11.97

33.40 ±

17.66

29.50 ±

8.84

29.70 ±

10.12

Neutrophil

(%)

66.90 ±

6.40

58.20 ±

4.56a

56.20 ±

2.97a

55.60 ±

4.06a

63.00 ±

2.78

Monocyte

(%)

6.30 ±

2.49

5.20 ±

2.20

8.80 ±

4.54

13.80 ±

7.92b

6.40 ±

2.17

Eosinophil

(%)

0.70 ±

1.05

1.90 ±

1.79a

1.10 ±

1.19

0.50 ±

0.84

0.40 ±

0.51

Basophiles

(%)

1.50 ±

1.84

0.90 ±

1.52

0.50 ±

0.52

0.80 ±

0.63

1.70 ±

0.67

a,bMean values with different superscripts in the column are significantly

different (p < 0.05).

4. DISCUSSION

All living beings on the earth are exposed to UV radia-

tion emitted from the sun. It is clear that previously ab-

sorbed UV radiation would affect the outcome of the

studies carried out on these living beings. On the other

hand, mole rats used in this study live in underground

galleries and are not exposed to sun emitted radiation. It

is too hard to observe the effect of UV radiation on vis-

cera of the animals that are exposed to sunlight all

through their life. Blood parameters play a very impor-

tant role in body functions and they are also affected

from sun light. For these reasons, we thought that mole

rats would be a better model to evaluate the effect of UV

radiation on hematological parameters.

Rats were exposed to UVC radiation and changes on

their hematological parameters were compared to base-

line (day 0) values. With UVC exposure, the erythrocyte

counts on day 14, 30 and 45 were found statistically sig-

nificant (p < 0.05). According to these data, a significant

decrease in erythrocyte values (from 8.76 ± 1.42 to 7.65

± 1.40) on the 14th, 30th days, but an increase (9.65 ±

0.89) was noted on the 45th day of UV exposure (Figure

2). Our findings correlate well with the data derived from

human, fish, rats and mice [11,17-19].

There was no significant effects of UVC on hemoglo-

bin value along the experiment (p > 0.05), however, sta-

H. Turker / American Journal of Molecular Biology 3 (2013) 235-240 237

Figure 2. Erythrocyte values.

tistically significant increase was noted on day 45 (13.60

± 0.81) (p < 0.05) (Figure 3). The increase is consistent

with the studies performed on humans [19] and rats [11],

but decrease in hemoglobin values were performed on

mice, calves, sheep and fish [9,17,18,20].

In our study, there was no statistically significant ef-

fects on hemotocyrite values along the UVC radiation

exposure (p > 0.05) (Figure 4). This finding was consis-

tent with the studies on primate and fish [8] and incon-

sistent with the studies on rats and fish [11,13,17,18].

Leukocyte counts showed significant increase with

UV radiation on day 30 and 45 (from 45.40 ± 19.31 to

54.40 ± 17.43) compared to the control group (p < 0.05)

(Figure 5). This might be due to the protection of the

organisms from the harmful effects of the sunlight. It has

been reported that even strain differences are the cause of

different immune responses to UV radiation [21]. The

increase of leukocyte numbers during the experiment

probably due to the secretion of IL-1 from melanocytes

and keratinocytes of skin via effects of UV radiation. IL-

1 activates bone marrow to release its leukocyte stores

into circulation [22]. Our results were consistent with the

studies on mice and rats [14,15], while no changes or

decrease in some studies [8,11,13,23,24].

In the present study, there was a significant effects of

UVC on lymphocyte percentage (p > 0.05) (Figure 6).

Similar results have been shown in some studies done

before [11,25,26].

In our study, with UV radiation a significant decrease

in the neutrophil, values (from 58.20 ± 4.56 to 55.60 ±

4.06) were observed on day 7, 14 and 30 compared to the

control group (p < 0.05) (Figure 7). These results were

consistent with the studies done on dogs and human [27,

28], but inconsistent with some studies on calves, pri-

mates and humans [8,20,29].

In the present study, a significant increase in monocyte

value (13.80 ± 7.92) was shown on day 30 (p < 0.05)

(Figure 8), but there were no significant effects on eosi-

nophil and basophile values during the UV experiment (p

> 0.05) (Figures 9 and 10). Our findings were correlated

with the studies carried out on primates, mice and rats

Figure 3. Hemoglobin values.

Figure 4. Hematocryte values.

Figure 5. Leukocyte values.

Figure 6. Lymphocyte values.

[8,10,15], but not correlated with the other studies in the

literature [12,25].

These results stressed that UVC radiation is also effec-

tive on the hematological parameters, like other types of

radiation. Animals exposed to radiation shows increased

H. Turker / American Journal of Molecular Biology 3 (2013) 235-240

238

“Far ultraviolet radiation” with a wavelength of 100 -

1700 A˚ has enough energy for ionization. This is the

type of ultraviolet radiation that is effective on the living

beings. The longer exposure time of UV radiation shows

more harmful effects on living beings. Loss in ozone

layer will result with increased UVC exposure that will

cause skin cancer, cataract and immune deficiency and

impairs blood parameters [1,7].

Hematological and biochemical blood parameters are

fundamental for the diagnosis of various diseases-both

metabolic and infectious [32]. Higher leukocyte values

indicate infectious disease. Heterophyl and eosinophil

increase point out microbial and parasitical infections

respectively and basophile domination indicates a para-

sitic disease [32,33].

Figure 7. Neutrophil values.

Figure 8. Monocyte values.

Figure 9. Eosinophil values.

Figure 10. Basophiles values.

leukocyte counts and some granulocyte counts. This is an

indicator of radiation provoked immune system damage

[15]. Increased erythrocyte and hemoglobin values in

mole rats, just like the Ostrichs, may be enlightened by

the ability of fast running and high oxygen consumption

and transport rates [30,31].

5. CONCLUSION

In conclusion, according to UV radiation exposure in

mole, rats were documented to cause some hematologi-

cal values along the experiment. There was a significant

increase in leukocyte counts, hemoglobin and monocyte

value and a decrease in erythrocyte number and neutro-

phil values during the experiment. Statistically signifi-

cant changes in hematocryte, eosinophil and basophile

values could not be documented. These results indicate

that the smaller wave UVC radiation has greater effects

on some blood parameters than the others.

6. ACKNOWLEDGEMENTS

The author thanks Ali BILGILI (Faculty of Veterinary Medicine, An-

kara University, Turkey) and Turan GUVEN (Gazi Education Faculty,

Department of Biology, Gazi University, Turkey) for assisting of ex-

periment and Levent ALTINTAS (Pharmacology and Toxicology

Department, Faculty of Veterinary Medicine, Ankara University, Tur-

key) for the biochemical exams and analysis of values.

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