Page 48 - World Journal of Laparoscopic Surgery

Effects of CO Pneumoperitoneum and Enteric Disturbance on β-endorphin in SD Rats
2
difference between group A and C was significant (P < colleagues measured a significant increase in β-EP levels
0.01). It was 3.77 ± 0.51 ng/ml, 2.99 ± 0.70 ng/ml and during acupuncture and transcutaneous stimulation even
2.67 ± 0.54 ng/ml at 10, 20 and 40 minutes respectively in before skin incision for abdominal surgery and also before
19
group C, vs 2.53 ± 0.86 ng/ml, 1.46 ± 0.11 ng/ml and 1.34 laryngoscopy for intubation had been performed. Elevated
± 0.14 ng/ml in group B (P < 0.01). serum EP and cortisol levels were observed in animals and
humans subjected to major stress. Hamit Okur et al reported
DISCUSSION that there was a linear correlation between β-EP and cortisol
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values and the injury severity. Increased β-EP and cortisol
Over the past few decades, corticotropin-releasing factor
(CRF) signaling pathways have been shown to be the main generation contributes to the acute phase reaction and
coordinators of endocrine, behavioral and immune responses hypermetabolic response that accompanies trauma. The
1-4
to stress. The central effectors of stress response are the secretion of cortisol plays a central role in mediating the
metabolic responses to stress. Under perioperative
corticotrophin-releasing hormone (CRH) and locus
coeruleus-norepinephrine (LC-NE) /sympathetic systems. conditions, corticotroph-type POMC derivatives such as
The CRH system activates stress response and is subject to ACTH or β-EP immunoreactive material (β-endorphin IRM)
modulation by cytokines, hormones and neurotransmitters. have been reported to be released in conditions of
preoperative stress, surgical injury, or postoperative
This stress system is tonically active, but both physical and 21,22
emotional stressors that exceed a critical threshold increase pain. Study of Marschall, et al indicates that although
its activity further. The principal role of glucocorticoids β-END and ACTH are both produced by the pituitary and
during the stress response is thought to be restraint of the derived from a common precursor, the type of stimuli (pre-
effectors of stress response. 5,6 vs postsurgical stress) seems to differentially affect their
23
β-EP is an opioid peptide representing the C-terminal 31 plasma levels.
acid residue fragment of proopiomelanocortin (POMC). The The stress response caused by surgery is conditioned
release of β-EP from the pituitary into the cardiovascular by several factors such as anxiety, incision size, enteric
disturbance (enteric exposure and drawing), exposure of
compartment under physical or emotional stress has been
frequently reported. It is well-established that in the pituitary abdominal organs to air, temperature change, operation
gland CRH stimulates the release of beta-endorphin via a duration, operated organ and operative type, pain,
7-9
cAMP-linked mechanism. Guillemin et al first reported hemorrhage and infection. Avoidance of enteric disturbance,
less hemorrhage, smaller incision size and shorter operation
that β-EP was released from the pituitary into the blood in
rats under stress, and that all kinds of stress could stimulate duration contribute to lowering stress response of
the secretion of serum β-EP, which was controlled by the laparoscopic surgery. To obtain excellent exposure in
hypothalamus, mainly by adenohypophysis synthesis, and laparotomy, it is necessary to incise the abdomen and pull
from POMC and its precursor substances. 10,11 The the intestine. As laparoscopic surgery and induction of
concentration of serum β-EP increased with stress responses pneumoperitoneum cause minimal activation of the stress
caused by different factors, reached the peak 5 ~ 10 minutes hormones, they should result in a lower stress response on
after continuum of the stress factors, and then decreased the part of the patient, and possibly a shorter recovery time.
gradually. But whether reducing intraoperative pulling of the intestine
In parallel with an increase in plasma β-EP concentration truly reduced the extent and shortened the duration of
during stress, an elevation in adrenocorticotropic hormone perioperative stress response, thus reducing trauma and
(ACTH) and cortisol plasma concentrations was observed. 12- promoting patient rehabilitation was not conclusive.
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Stress could stimulate the secretion of serum β-EP, inhibit The results of this study show that serum β-EP was
activity of the sympathetic-adrenal system, regulate the stress elevated, and the degree of elevation was related to the
intensity, and inhibit secretion of ACTH, glucocorticoid and severity of injury. Surgery is a stressful stimulus that elicits
15
vasopressin. H. Harbach et al found cortisol as a ‘long- inflammatory, endocrine and metabolic responses consisting
term parameter’ of the endocrine response to stress. 16-18 In of increased levels of stress hormones, leading to substrate
their previous studies, β-endorphin was measured under mobilization. 24,25 These changes together constitute the stress
different stress conditions. In parallel with an increase in β- response. Laparoscopic surgery causes minimal activation
EP concentrations during stress, an elevation in ACTH and of the stress hormones while laparotomy results in a more
plasma cortisol concentrations was observed. Kho and obvious response of the stress hormones, probably due to

World Journal of Laparoscopic Surgery, January-April 2010;3(1):49-53 51