
Oxidative Stress in castrated cats / Polat et al. ______________________________________________________________________________________
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INTRODUCTION
Castration is the process of eliminating the source of hormones 
that create sex–related physical and behavioral characteristics in 
order to prevent reproduction in male cats (Felis catus) and dogs 
(Canis lupus familiaris). Surgical removal of testicles is the most widely 
used castration technique in all mammalian species [1, 2]. In many 
Countries (such as USA, England), castration processes are used 
to prevent the uncontrolled population growth of cats and dogs. 
However, in some Countries (such as Germany, Norway, Sweden), 
castration is seen as an unethical practice [1, 3].
It has been stated by some international organizations (American 
Veterinary Medical Association, American Animal Hospital Association, 
British Small Animal Veterinary Association) that castration in 
the prepubertal period is acceptable. In some studies [1, 4], it has 
been stated that castrations performed at an early age in cats and 
dogs have no or very few side effects. However, many veterinarians 
oppose castration in the prepubertal period due to the orthopedic and 
oncological risks that may occur in later ages [1, 5]. In addition, it also 
causes problems such as the narrowing of the urethra, which prevents 
the urinary catheter from passing, and the increase in obesity.
Today, there are discussions about the advantages and 
disadvantages of the castration process. With the castration process, 
the excessive increase in cat and dog populations are prevented, the 
risk of formation of some genital system diseases (some prostate 
pathologies, some testicular tumors) and the control of unwanted 
behaviors (aggression, urinating in inappropriate places) are provided 
[1, 2]. Again, some studies report that the life span of castrated cats 
and dogs is prolonged [6, 7]. Castration has both advantages and 
disadvantages. Some studies have found an increased incidence 
of osteosarcoma and prostate tumors in castrated cats [1, 8, 9, 10]. 
Again, some studies report an increased risk of obesity [11, 12, 13], 
some orthopedic problems [14, 15], and diabetes mellitus (especially 
Burmese breed) [1, 16] in cats after castration.
It is known that the castration process has an effect on some 
hematological parameters and the levels of oxidative stress factors 
[2, 17, 18]. Aengwanich et al. [2] reported that there were signicant 
changes in the neutrophil/lymphocyte ratio in dogs after castration 
(surgical method). Surgical operations are one of the important stress 
factors for living beings. The deterioration of the oxidant/antioxidant 
balance in the body in favor of oxidants under the inuence of any 
stress factor is called oxidative stress. Oxidative stress causes the 
body's resistance to degenerative diseases to decrease. In addition 
to causing cardiovascular system diseases and neurodegenerative 
central nervous system diseases, it also causes oncological diseases by 
damaging the Deoxyribonucleic acid (DNA) helix [2, 19, 20, 21, 22, 23, 24].
In this study, changes in some blood parameters and oxidative stress 
factors in preoperative and postoperative periods were evaluated in 
castrated cats. Thus, by investigating the effect of castration on the 
formation of oxidative stress, it was aimed to evaluate the decrease 
or increase in body resistance against some degenerative diseases in 
the body. At the same time, it was determined whether the castration 
process would cause a change in some blood parameters, and its 
effect on the health status of cats was investigated.
MATERIALS AND METHODS
Ethical approval and study plan
This study was carried out in accordance with ethical principles 
with the approval of Fırat University Animal Experiments Local Ethics 
Committee (dated: 22.03.2021, numbered: 28617). The study was 
carried out on 19 cats brought to Fırat University Animal Hospital 
Surgery Clinic for castration. In the study, the changes in the levels 
of some blood parameters and oxidative stress factors in the 
preoperative and postoperative period of the cats were evaluated.
Collecting blood samples
For the study, 5 mL blood was collected from cats both in tubes with 
10% Ethylenediaminetetraacetic acid (EDTA) and in tubes with vacuum 
gel and clot activator on the preoperative and postoperative 10th day. The 
cephalic vein in the forearm was used when blood samples were taken.
Anesthesia and castration procedure
Before the castration procedure, 2 mg·kg
-1
 Xylazine hydrochloride 
was administered intramuscularly to the cats. After 10 min, anesthesia 
was achieved by administering Ketamine hydrochloride at a dose of 
10 mg·kg
-1
 intramuscularly [25].
After shaving and disinfection of the scrotum of the cats, the 
operation area was limited to the operation cover. The testicles were 
limited and the scrotum skin was tightened (FIG. 1A). An incision 
long enough for the testicles to protrude was made into the skin of 
the scrotum, parallel to the raphe scroti (FIG. 1B,1C). After the soft 
tissues and tunica vaginalis were cut, the testis was taken out and 
separated from all its connections (FIG. 1D). After the hemostatic 
forceps were placed on the part of the testicular cord towards the 
body, a ligature was applied by transxation method using absorbable 
suture material (FIG. 1E,1F). The same procedure was performed 
for the second testis. In the postoperative period, Povidin–iodine 
solution was applied to the operation wound for 3 days (d) and 
parenteral antibiotics (Sülcid, 0.25mg) were administered for 3 d. 
For postoperative pain management, 0.2 mg·kg
-1
 meloxicam was 
administered subcutaneously to all cats.
The cats that made up the material of the study were from different 
breeds, aged 12–36 months. The surgeons performing and assisting 
the operations were the same in all operations. Each of the operations 
lasted an average of 3–4 min. All cats included in this study were 
castrated during the summer months.
Measurement of hematological parameters
Hemogram and leukogram values of the cats were done with whole 
blood analyzer (Hasvet Mindray BC–5000 Vet branded, Turkey). In order 
to determine the oxidative stress factors, blood samples in tubes with 
vacuum gel and clot activator were centrifuged at 3000 G for 10 min.
Determination of total oxidant status (TOS) activity
TOS activity of serum tissue was studied using Total Oxidant Status 
kit (Rel Assay Diagnostics). 250 µL of buffer solution was added to all 
wells. 37 µL of standard sample was added to the standard well and 
37 µL of sample was added to the sample well. The rst reading was 
made at 530 nm. 12 µL of substrate solution was added to all wells and 
incubated at room temperature (20 – 25°C) for 10 min with shaking.