______________________________________________________________________Revista Cientifica, FCV-LUZ / Vol. XXXIII, rcfcv-e33260, 1 – 9
7 of 9
The results of this study showed that the vital parameters of heart
rate, respiration, and temperature were depressed at 2 h post-OHE
and then returned to normal after the recovery phase. In the study,
anesthesia was provided with Ketamine, a centrally effective
N-methyl-D-aspartate (NMDA) antagonist, and xylazine, an alpha 2
adrenergic receptor agonist. The suppression of all vital parameters
at 2 h post-OHE shows that the depth of pharmacological action of
the anesthetics continued. With the return of vital values to normal
levels in the following h the effect of the anesthetics was seen to
have disappeared. Numerous studies that have used various surgical
procedures and anesthesia regimens to assess the alterations in
hematochemical parameters in OHE bitches have reported varying
results [16]. Intraoperative blood loss of less than 15% of blood
volume is not anticipated to result in clinical symptoms in non-anemic
human patients, although the loss of less than 30% of intraoperative
blood volume has been proposed as a red cell transfusion trigger in
otherwise healthy people [17].
Dogs (Canis lupus familiaris) and cats have been reported to be
more likely to develop hospital-acquired anemia when cumulative
phlebotomy volumes exceed 3% of their total blood volume and when
undergoing surgery [18]. No difference in RBC, Hb, Hct, MCV, MCHC,
PLT and MPV values was determined in the current study, which was
consistent with the ndings of a previous study of OHE in cats [19].
This can be attributed to the fact that the OHE surgery performed
was minimally invasive with minimal bleeding.
OHE is an intrusive operation with postoperative pain ranging from
mild to severe [5, 20]. Surgical trauma induces a stress reaction
and increases muscle activity because of injury to superficial
nerve terminals, which stimulates the corticotropic releasing
hormone (CRH). Following hypothalamic activation, CRH promotes
adrenocorticotropin hormone (ACTH) and causes the adrenal
gland to produce cortisol [21]. As a result of tissue damage, organ
manipulation, and inammation, OHE is well known to produce pain
and stress. In a previous study, 2 h after OHE, dogs had considerably
greater peak plasma cortisol levels [22]. Neutrophils migrate from
the neutrophil pool to the circulating neutrophil pool in response to
cortisol, although this can also be augmented by neutrophil release
from the bone marrow storage pool and decreased migration of
neutrophils to tissues [23]. It has been reported that neutrophilia
and lymphocytopenia are seen in dogs undergoing OHE [24]. Another
study of dogs showed that OHE led to stress leukogram such as
leukocytosis, neutrophilia, lymphocytopenia, and eosinopenia [25].
However, in a recent study of cats, neutrophilia and lymphocytopenia
were observed on the 2nd d after OHE, and eosinophilia on the 10thd
[19]. In the current study, leukocytosis with neutrophilia started to
appear at 2 h after OHE and peaked at 24 h, but then returned to
the baseline level. However, lymphocytopenia, monocytopenia, and
interestingly eosinophilia was noted in the cats after OHE in the
current study. This may have been due to circulating stress hormones
originating from OHE.
NLR, PLR, MLR, and MPV/PLT are biomarkers of systemic
inammatory response, which are potentially diagnostic [26, 27].
There is a growing amount of evidence indicating the potential utility
of these indexes in veterinary care. Previous research in veterinary
medicine has associated increased NLR with canine sepsis [26], dogs
with chronic enteropathy [28], feline hypertrophic cardiomyopathy
[29], and tumor size in cats [30]. Recently, ndings have been reported
proving that NLR can be an effective stress and inammation marker
in cats undergoing OHE [19]. In the current study, NLR increased in
the rst two h following OHE, peaked in the next 24 h, and then started
to decline on the 7
th
d to the pre-OHE level.
Previous studies support that this may be related to OHE-induced
stress and inammatory status. Related to systemic inammatory
reactive diseases and PLT function and activity, the rise in PLR has
been reported to be caused by an increase in platelet count and a
reduction in lymphocyte count in peripheral blood [31]. Increased
thrombopoietin and cytokine levels during inammation result in
increased megakaryocytes, which stimulate PLT production and
decrease their size [32]. PLT are important in initial hemostasis
because they adhere to the damaged vascular bed induced by
subendothelial collagen exposure [33]. MPV/PLT and PLR indices
have been previously shown to be ineffective as systemic biomarkers
for disease activity in dogs, such as periodontitis and oropharyngeal
cancers [27]. In a previous study, increases in the mean PLT values
were observed in cats after OHE [34], whereas another cat study
showed that PLT, MPV and PLR were not significantly changed
post-OHE [19]. PLR increased following OHE in the current study,
and the MPV/PLT ratio decreased on the 7
th
d post-OHE. In general,
stress-induced hypercortisolemia, followed by platelet release into
blood cells and transient lymphopenia, inuences the degree of PLR
elevation in a variety of proinammatory and prothrombotic states
[31]. MLR is a simple biomarker of the host immune system. Research
has linked a high monocyte count to immune gene upregulation
and the generation of monocyte/macrophage-related cytokines
[35]. Although a previous study showed that monocyte levels did
not change, lymphocytes decreased after OHE in cats [19]. Another
study of domestic dogs in Nigeria reported a decrease in monocyte
levels 2 h after OHE, returning to pre-OHE levels, while decreased
lymphocyte levels were reported [3]. MLR and NLR formed similar
curves in the current study, increasing at 2 h post-OHE, peaking at
24 h, and then reverting to normal on the 7
th
d. OHE-induced stress
and inammation may have contributed to this response.
Native thiols (–SH) and total thiols (–SH+ –SS) are critical for the
detoxication of extracellular and intracellular reactive nitrogen and
oxygen species, which is a crucial component of cellular antioxidant
defences. Importantly, this oversees preservation of the redox state
of protein thiols necessary for deoxyribonucleic acid (DNA) synthesis
and repair [13]. Protein structural and functional alterations are
commonly caused by the loss of thiol groups, which is the principal
molecular process. It has been reported that surgery and trauma
decrease protein synthesis and increase protein catabolism and
oxidation, and these changes are related to the level and duration
of trauma [36]. In a previous study, total thiol was reported to be
a therapeutically relevant indicator of oxidative stress in cats with
pyometra that had undergone elective OHE [37]. In the current study,
it was hypothesized that the body's efforts to detoxify oxidative stress
and the oxygen free radicals generated by surgical trauma would be
the main cause of the greatly reduced thiol levels post-OHE. The
study results showed that natural and total thiol have a very high
negative correlation with NLR, a strong negative correlation with
MLR, and a moderate negative correlation with PLR. However, MPV/
PLT and native and total thiol did not correlate. Although there are
many human studies in the literature to explain the relationship
between thiols and NLR, PLR, and MLR, animal research is limited.
A negative correlation has been previously reported between NLR
and native and total thiol after gunshot injury in humans [38]. Total
thiol and native thiol levels have also been shown to be positively
correlated with lymphocyte levels and negatively correlated with NLR