Electroacupuncture suppresses surgical trauma stress-induced lymphocyte apoptosis in rats

Can peri-surgical electroacupuncture relieve immunity suppression? A pilot study in dogs

General anesthesia and surgical stress can suppress the immunological response by acting both directly on the immune system and indirectly on the hypothalamic-pituitary-adrenal axis and the sympathetic nervous system. Disturbance of the immune system during the perioperative period can lead to complications such as wound-healing disorders and infections up to sepsis. Effectiveness of acupuncture in regulating the immune function by increasing leukocyte numbers and inhibiting inflammatory response has been proven. This study aimed to explore the impact of electroacupuncture (EAP) on the dynamic balance of the immune system and immune cell populations in dogs undergoing surgery. Twelve healthy bitches scheduled for elective ovariectomy were divided into two groups according to whether (EAP, n=6) or not (CTR, n=6) a peri-operative electroacupuncture treatment was performed. Levels of leukocytes (neutrophils, monocytes, T- and B-cells) and immunoglobulins M (IgM) and A (IgA) were measured in blood samples collected before (T0), 1 h (T1) and 2.5 h (T2) after anesthesia induction. Leukocytes count decreased from T0 to T1 in both groups and restored within 1.5 h in EAP group whereas remained significantly lower in CTR group (P<0.02). In particular, neutrophils and monocytes increased in dogs receiving EAP (P<0.01) while T-cells decreased in CTR group (P<0.04) at T2. B-cells and cytotoxic T-cells decreased in EAP dogs (P<0.04) at T2. No differences in helper T-cells, IgM and IgA levels were recorded between groups and over time. Our results suggest a modulatory effect of EAP on the immune system which is early expressed on neutrophils, monocytes and T-cells.

The autonomic nervous system: A potential link to the efficacy of acupuncture

The autonomic nervous system (ANS) is a diffuse network that regulates physiological systems to maintain body homeostasis by integrating inputs from the internal and external environment, including the sympathetic, parasympathetic, and enteric nervous systems (ENS). Recent evidence suggests that ANS is one of the key neural pathways for acupuncture signal transduction, which has attracted worldwide attention in the acupuncture field. Here, we reviewed the basic and clinical research published in PubMed over the past 20 years on the effects of acupuncture on ANS regulation and homeostasis maintenance. It was found that acupuncture effectively alleviates ANS dysfunction-associated symptoms in its indications, such as migraine, depression, insomnia, functional dyspepsia, functional constipation. Acupuncture stimulation on some specific acupoints activates sensory nerve fibers, the spinal cord, and the brain. Using information integration and efferents from a complex network of autonomic nuclei of the brain, such as the insular cortex (IC), prefrontal cortex, anterior cingulate cortex (ACC), amygdala (AMG), hypothalamus, periaqueductal gray (PAG), nucleus tractus solitarius (NTS), ventrolateral medulla (VLM), nucleus ambiguus (AMB), acupuncture alleviates visceral dysfunction, inflammation via efferent autonomic nerves, and relieves pain and pain affect. The modulating pattern of sympathetic and parasympathetic nerves is associated with acupuncture stimulation on specific acupoints, intervention parameters, and disease models, and the relationships among them require further exploration. In conclusion, ANS is one of the therapeutic targets for acupuncture and mediates acupuncture's actions, which restores homeostasis. A systemic study is needed to determine the rules and mechanisms underlying the effects of acupoint stimulation on corresponding organs mediated by specific central nervous networks and the efferent ANS.

Electroacupuncture Attenuates Surgical Stress-Induced Reduction of T Lymphocytes through Modulation of Peripheral Opioid System

OBJECTIVE

To investigate the action mechanisms of electroacupuncture (EA) on postoperative immunosuppression.

METHODS

Male C57BL/6 mice (5`-7 weeks old) were randomly divided into: the sham injury group, the surgical trauma stressed group, the EA group [surgery + 2/100 Hz EA at Neiguan (PC 6)], and the EA+ Nal (surgery + EA + intraperitoneal injection of naloxone). Abdominal surgical trauma stress mice model was established. EA was performed on bilateral PC 6 acupoints by an EA apparatus (2/100 Hz) for 20 min once a day for 3 days. The mRNA expressions of MOR, DOR, and KOR in thymus and L3`-L5 dorsal root ganglions (DRG) were determined by quantitative real-time polymerase chain reaction (qRT-PCR) and the protein expressions of MOR, DOR, and KOR in thymus were measured by Western blot. Flow cytometry assay was used to detect the levels of T lymphocyte subtypes in the peripheral blood.

RESULTS

Surgical trauma induced decreased the mRNA expression level of MOR in both thymus (P<0.01) and L3`-L5 DRGs (P<0.05). Moreover, EA treatment not only significantly attenuated the MOR protein and mRNA expression in the thymus (both P<0.05), but also markedly increased expression of DOR and KOR opioid receptor in thymus (P<0.01). However, the mRNA expressions of opioid receptors were not regulated by EA in the DRG (all P>0.05). Furthermore, T lymphocyte population of CD3⁺ and CD4⁺ was decreased in the peripheral blood after surgical trauma (both P<0.01). EA treatment can significantly elevate the population of CD₃⁺ (P<0.01), CD₄⁺ (P<0.05) and CD₈⁺ T cells (P<0.01). Intraperitoneal injection of the non-selective opioid receptor antagonist naloxone blocked the up-regulation of T lymphocytes by EA.

CONCLUSION

EA may improve postoperative immunosuppression through the peripheral opioid system.

Effects of perioperative transcutaneous electrical acupoint stimulation on monocytic HLA-DR expression in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass: study protocol for a double-blind randomized controlled trial

BACKGROUND

Cardiac surgery involving cardiopulmonary bypass (CPB) is known to be associated with a transient postoperative immunosuppression. When severe and persistent, this immune dysfunction predisposes patients to infectious complications, which contributes to a prolonged stay in the intensive care unit (ICU), and even mortality. Effective prevention and treatment methods are still lacking. Recent studies revealed that acupuncture-related techniques, such as electroacupuncture and transcutaneous electrical acupoint stimulation (TEAS), are able to produce effective cardioprotection and immunomodulation in adult and pediatric patients undergoing cardiac surgery with CPB, which leads to enhanced recovery. However, whether perioperative application of TEAS, a non-invasive technique, is able to improve immunosuppression of the patients with post-cardiosurgical conditions is unknown. Thus, as a preliminary study, the main objective is to evaluate the effects of TEAS on the postoperative expression of monocytic human leukocyte antigen (-D related) (mHLA-DR), a standardized "global" biomarker of injury or sepsis-associated immunosuppression, in patients receiving on-pump coronary artery bypass grafting (CABG).

METHODS

This study is a single-center clinical trial. The 88 patients scheduled to receive CABG under CPB will be randomized into two groups: the group receiving TEAS, and the group receiving transcutaneous acupoint pseudo-electric stimulation (Sham TEAS). Expression of mHLA-DR serves as a primary endpoint, and other laboratory parameters (e.g., interleukin [IL]-6, IL-10) and clinical outcomes (e.g., postoperative infectious complications, ICU stay time, and mortality) as the secondary endpoints. In addition, immune indicators, such as high mobility group box 1 protein and regulatory T cells will also be measured.

DISCUSSION

The current study is a preliminary monocentric clinical trial with a non-clinical primary endpoint, expression of mHLA-DR, aiming at determining whether perioperative application of TEAS has a potential to reverse CABG-associated immunosuppression. Although the immediate clinical impact of this study is limited, its results would inform further large-sample clinical trials using relevant patient-centered clinical outcomes as primary endpoints.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02933996. Registered on 13 October 2016.

Nerve Stimulation: Immunomodulation and Control of Inflammation

Neuronal stimulation is an emerging field in modern medicine to control organ function and re-establish physiological homeostasis during illness. Transdermal nerve stimulation with electroacupuncture is currently endorsed by the World Health Organization (WHO) and the National Institutes of Health (NIH), and is used by millions of people to control pain and inflammation. Recent advances in electroacupuncture may permit activation of specific neuronal networks to prevent organ damage in inflammatory and infectious disorders. Experimental studies of nerve stimulation are also providing new information on the functional organization of the nervous system to control inflammation and its clinical implications in infectious and inflammatory disorders. These studies may allow the design of novel non-invasive techniques for nerve stimulation to help to control immune and organ functions.

Modulation of Acupuncture on Cell Apoptosis and Autophagy

Acupuncture has been historically practiced to treat medical disorders by mechanically stimulating specific acupoints. Despite its well-documented efficacy, its biological basis largely remains elusive. Recent studies suggested that cell apoptosis and autophagy might play key roles in acupuncture therapy. Therefore, we searched PubMed, Embase, Web of Science, and China National Knowledge Infrastructure (CNKI), aiming to find the potential relationship between acupuncture and cell apoptosis and autophagy. To provide readers with objective evidence, some problems regarding the design method, acupoints selection, acupuncture intervention measure, and related diseases existing in 40 related researches were shown in this review. These findings demonstrated that acupuncture has a potential role in modulating cell apoptosis and autophagy in animal models, suggesting it as a candidate mechanism in acupuncture therapy to maintain physiologic homeostasis.

p38 Mitogen-activated protein kinase is required for electroacupuncture restoration of CD4+/CD8+ homeostasis and cytokine expression in a rodent model of surgical trauma

Cumulative evidences addressed that electroacupuncture (EA) was favorably effective in the treatment of trauma stress-induced immunodeficiency and physical disorders. However, the salutary effects of EA under operation trauma conditions mediated via p38 MAPK remain unknown. Hence, our study aimed to further investigate the effects of EA on CD4(+)/CD8(+) homeostasis and cytokine expressions, and evaluate the p38 MAPK signaling regulatory mechanism of EA effects.

Novel polyacetylenes from Coreopsis tinctoria Nutt

Phytochemical investigation of the 95% EtOH extract of Coreopsis tinctoria Nutt. resulted in the isolation of two novel polyacetylenes, (2S)-(3Z,11E)-decadiene-5,7,9-triyne-1,2-diol (1) and (2R)-(3E,11Z)-decadiene-5,7,9-triyne-1,2-diol (2), together with two known polyacetylenes (3 and 4). The structures of these novel compounds were determined by extensive two-dimensional nuclear magnetic resonance, high-resolution mass spectrometry, and optical rotation. Compounds 1, 2, and 4 were evaluated for their anti-proliferative activities against C26 cell growth and inhibitory effects on the lipo-poly-saccharides-induced nitric oxide production using murine macrophage RAW 264.7 cells. However, compounds 1, 2, and 4 just showed weak activities.

Electroacupuncture inhibits apoptosis of splenic lymphocytes in traumatized rats through modulation of the TNF-α/NF-κB signaling pathway

Surgical trauma leads to a severe deterioration of the immune system. Electroacupuncture (EA) may improve the immunodeficiency that occurs following surgery; however, the underlying signaling mechanisms require further study. In the present study, 40 rats were equally randomized into four groups: Control; Control + EA; Trauma; Trauma + EA. EA was applied at the 'Zusanli' (ST36) and 'Lanwei' (Extra37) acupoints, immediately following surgery. The splenic T cells were isolated from the rats 24 h after surgery. The apoptotic rate of the lymphocytes was measured by flow cytometric analysis, and western blotting was used to determine the protein expression levels of caspase-3, caspase-8, tumor necrosis factor (TNF)-α and TNF receptor 1 (TNFR1). The DNA binding activity of nuclear factor (NF)-κB was determined using Trans-AM® ELISA-based kits. The results of the present study showed that surgical trauma induced apoptosis of splenic lymphocytes, and significantly increased the protein expression levels of caspase-3 and caspase-8. This was accompanied by increased expression levels of TNF-α and TNFR1, and a marked reduction in the activity of NF-κB in splenic T cells. Administration of EA significantly decreased the expression levels of caspase-3, caspase-8, TNF-α and TNFR1, elevated the activity of NF-κB, and suppressed the apoptotic rate of the lymphocytes. The data suggests that EA may inhibit the apoptosis of splenic lymphocytes induced by surgical trauma, and ameliorate the postoperative immunosuppression. This may be mediated by the downregulation of TNF-α expression levels and upregulation of the activity of NF-κB.

Role of HO-1 in protective effect of electro-acupuncture against endotoxin shock-induced acute lung injury in rabbits

Heme oxygenase (HO)-1 has been reported to play a great role in attenuating lung injury during endotoxic shock in our previous research. Although electro-acupuncture has been explored to reduce oxidative stress and decrease inflammatory reaction in animals with endotoxic shock, the mechanism of this effect is still unclear. The aim of this study was to determine whether HO-1 is involved in the effect of electro-acupuncture on the injured lung during endotoxic shock in rabbits. Sixty New England white rabbits were randomly divided into groups C, Z, ES, EA, AP, and EAZ. Before inducing endotoxic shock, group ES received no electro-acupuncture, while group EA received electro-acupuncture at ST36 (zusanli) and BL13 (feishu) acupoints on both sides for five days and group AP received electro-acupuncture (EA) stimulation at a non-acupoint. Groups ES, AP, EA, and EAZ received LPS to replicate the experimental model of injured lung induced by endotoxic shock, and electro-acupuncture was performed throughout the procedure with the same parameter. Groups EAZ and Z received the HO-1 inhibitor, ZnPP-IX, intraperitoneally. The animals were sacrificed by blood-letting at 6 h after LPS administration. The blood samples were collected for serum examination, and the lungs were removed for pathology examination, detection of alveolaer epithelial cell apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay (TUNEL assay), determination of wet to dry ratio, measurement of Evans blue (EB) contents, and determination of HO-1protein and mRNA expression. According to the results, EA at ST36 and BL13 could increase the expression of HO-1. At the same time, index of quantitative assessment (IQA) score and the number of TUNEL-positive cells decreased, while electro-acupuncture at the other points did not exert this effect, and pretreatment with ZnPP-IX in group EAZ suppressed the efficacy of electro-acupuncture preconditioning. In summary, electro-acupuncture stimulation at ST36 and BL13, while not the non-acupoint, could attenuate the lung injury during the endotoxic shock, and this effect was due to increased expression of HO-1.

Effects of electroacupuncture at Zusanli (ST36) on inflammatory cytokines in a rat model of smoke-induced chronic obstructive pulmonary disease

OBJECTIVE

Improvement in lung function was reported after acupuncture treatment of chronic obstructive pulmonary disease (COPD), but little is known about the underlying mechanisms. Because an immune response imbalance could be seen in COPD, we hypothesize that electroacupuncture (EA) may play a role in regulating inflammatory cytokines and contribute to lung protection in a rat model of smoke-induced COPD.

METHODS

A COPD model using male Sprague-Dawley rats exposed to cigarette smoke was established. The rats were randomly divided into four groups (control, sham, COPD, and COPD plus EA), and COPD model was evaluated by measuring pulmonary pathological changes and lung function. EA was applied to the acupuncture point Zusanli (ST36) for 30 min/d for 14 d in sham and COPD rats. Bronchoalveolar lavage fluid (BALF) was used to measure levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and malonaldehyde (MDA).

RESULTS

Compared with the control rats, COPD rats had significant changes in lung resistance (RL) and lung compliance (CL) (both P<0.01), bronchi and bronchiole airway obstruction (P<0.01), and levels of MDA, TNF-α, and IL-1β (P<0.01). There were no significant differences between the control and the sham groups. Compared with the COPD rats, the COPD plus EA rats had decreased RL and increased CL (both P<0.05), and reduced bronchi and bronchiole airway obstruction (P<0.05, P<0.01, respectively), while levels of TNF-α, IL-1β, and MDA in BALF were lowered (P<0.05 and P<0.01, respectively). However, TNF-α and IL-1β levels of the EA group rats remained higher than those of the control group (P<0.05).

CONCLUSION

EA at ST36 can reduce lung injury in a COPD rat model, and beneficial effects may be related to down-regulation of inflammatory cytokines. The anti-inflammatory and antioxidant effects may prolong the clinical benefit of EA.

Electroacupuncture inhibits apoptosis in annulus fibrosis cells through suppression of the mitochondria-dependent pathway in a rat model of cervical intervertebral disc degradation

The purpose of this study was to investigate whether treatment with electroacupuncture (EA) inhibited mitochondria-dependent apoptosis in annulus fibrosis (AF) cells in a rat model of cervical intervertebral disc degradation induced by unbalanced dynamic and static forces. Forty Sprague-Dawley rats were used in this study, of which 30 underwent surgery to induce cervical intervertebral disc degradation, 10 rats received EA at acupoints Dazhui (DU 14) and Shousanli (LI 10). TUNEL staining was measured to assess apoptosis in AF cells, immunohistochemistry was used to examine Bcl-2 and Bax expression, colorimetric assays were used to determine caspase 9 and caspase 3 activities and RT-PCR and western blotting were used to assess the mRNA and protein expression of Crk and ERK2. Treatment with EA reduced the number of AF-positive cells in TUNEL staining, increased Bcl-2-positive cells and decreased Bax-positive cells in immunohistochemical staining, significantly inhibited the activation of caspases-9 and -3, and enhanced the mRNA and protein expression of Crk and ERK2. Our data show that EA inhibits AF cell apoptosis via the mitochondria-dependent pathway and up-regulates Crk and ERK2 expression. These results suggest that treatment with may be a good alternative therapy for preventing cervical spondylosis.

Acupuncture and Immunomodulation

Acupuncture is a well-known form of Asian medical treatment and it is used not only as an effective curative method but also to prevent illness and mai ntain health. It is used for the production of analgesic effect; stress related physical-mental disorders and homeostasis. Electroacupuncture (EA) stimulation, an application of electrical current on acupuncture needles, is one of the most popular types of this traditional therapy. In recent years, intensive studies have been carried out to explain the underlying mechanisms of the efficacy of acupuncture. An increase in the release of endogen opioid peptides is generally accepted to be a keystone pathway that affects the immune system after the acupuncture application. To understand the huge gap between specific skin point applications and immune responses, a vast number of accumulating data of experimental and clinical studies in the literature have been collected. This paper reviews the data to explain the updated mechanisms related to immune modulation via acupuncture therapy.

The effects of electroacupuncture on TH1/TH2 cytokine mRNA expression and mitogen-activated protein kinase signaling pathways in the splenic T cells of traumatized rats

BACKGROUND

Surgical trauma contributes to postoperative immune suppression, which is associated with an increased susceptibility to subsequent infections. Electroacupuncture (EA) can alleviate pain and exert immunoregulatory effects. However, the mechanism underlying the immnuomodulation effects of EA is not fully elucidated. Therefore, we investigated the effects of EA on T helper (Th)1/Th2 cytokine production and mRNA expression and evaluated the signaling regulatory mechanism of EA effects.

METHODS

Rats were divided into four groups (n = 24 each): control, trauma, trauma (T) + sham EA, and T + EA. EA was applied to Zusanli (ST36) and Lanwei (Extra37) acupoints at 20 min after surgery for 30 min, and then performed once a day on postoperative days 1-5. Splenic T cells were isolated and the production and mRNA expression of interleukin (IL)-2, interferon-gamma, IL-4, and IL-10 were assayed. The activation of mitogen-activated protein kinase and the DNA binding activity of nuclear factor (NF)-kappaB and activator protein (AP)-1 were examined.

RESULTS

Paw withdrawal threshold and paw withdrawal latency were significantly increased in the T + EA group compared with the trauma group from postoperative day 1 (paw withdrawal threshold: 5.8 +/- 0.7 vs 3.0 +/- 0.7 g; paw withdrawal latency: 7.0 +/- 0.8 vs 4.5 +/- 0.5 s; P < 0.001) to day 5 (9.0 +/- 0.6 vs 5.5 +/- 0.6 g; 12.0 +/- 1.3 vs 7.0 +/- 0.8 s; P < 0.001). Th1 cytokine (IL-2 and interferon-gamma) production and mRNA expression in splenic T cells of traumatized rats were significantly decreased on postoperative day 3 (P < 0.001, trauma group versus control group), whereas Th2 cytokine (IL-4 and IL-10) production and mRNA expression were increased (P < 0.001). This was accompanied with a significant depression in the activity of extracellular-regulated protein kinase (ERK)1/2, p38, NF-kappaB, and AP-1 (P < 0.001, trauma group versus control group). EA administration increased Th1 cytokine protein and mRNA expression, suppressed Th2 cytokine protein and mRNA expression (P < 0.05, T + EA group versus trauma group), and increased the activity of ERK1/2, p38, NF-kappaB, and AP-1 (P < 0.001, T + EA group versus trauma group).

CONCLUSIONS

EA regulates a balance between Th1 and Th2 cytokines at protein and mRNA levels in splenic T cells, and, at least in part, involves the signaling pathways of ERK1/2, p38, NF-kappaB, and AP-1. The findings suggest that EA may improve immune suppression after surgical trauma.

Electroacupuncture downregulates TLR2/4 and pro-inflammatory cytokine expression after surgical trauma stress without adrenal glands involvement

Cumulative evidences suggest that electroacupuncture (EA) can modulate immune function, but the mechanism needs further study. In the present study, the contribution of EA on toll-like receptors 2 and 4 (TLR2/TLR4) and pro-inflammatory cytokine expression after surgical trauma stress were investigated. The mRNA level of both TLR2/4 and pro-inflammatory cytokine was measured by quantitative real-time PCR. ELISA and Western blot assay were chosen for TLR2/TLR4 protein expression and pro-inflammatory cytokine production, respectively. The results showed that surgical trauma stress increased TLR2 mRNA and TLR2/4 proteins in the spleen and augmented pro-inflammatory cytokines (e.g. IL-1beta) mRNA and protein expression in the spleen and plasma. These effects could be deteriorated by adrenalectomy (ADX). EA at "Zusanli" acupoint significantly inhibited surgical trauma-induced TLR2 mRNA and TLR2/4 protein expression in spleen and pro-inflammatory cytokine expression in the spleen and plasma. ADX, however, could not block the effect of EA. These results suggested that surgical trauma stress primes the innate immune system for enhanced TLR2 expression and pro-inflammatory cytokine production. EA inhibits TLR2/4 and pro-inflammatory cytokines to produce an anti-inflammatory effect in a surgical trauma stress model, without adrenal gland involvement.

Non-pharmacological techniques for pain management in neonates

Significant progress in understanding the physiology, clinical correlates, and consequences of neonatal pain have resulted in greater attention to pain management during neonatal intensive care. A number of nonpharmacological therapies have been investigated, including nonnutritive sucking, with and without sucrose use, swaddling or facilitated tucking, kangaroo care, music therapy, and multi-sensorial stimulation. Although the efficacy of these approaches is clearly evident, they cannot provide analgesia for moderate or severe pain in the neonate. Further, some of these therapies cannot be effectively applied to all populations of critically ill neonates. Acupuncture, an ancient practice in Chinese medicine, has gained increasing popularity for symptom control among adults and older children. Acupuncture may provide an effective nonpharmacological approach for the treatment of pain in neonates, even moderate or severe pain, and should be considered for inclusion in a graduated multidisciplinary algorithm for neonatal pain management.

Sympathetic nervous system mediates surgical trauma stress-induced splenocyte apoptosis in rats

Surgical trauma stress has been reported to induce immunosuppression. The mechanisms involved are still unclear. The present study was designed to assess the role of the sympathetic nervous system in regulating splenocyte apoptosis induced by surgical trauma stress. Our results showed that the rats that underwent surgical trauma stress exhibited a significant reduction in splenic cellularity, the loss of splenocytes was likely mediated by apoptosis, for a substantial increase in apoptosis was observed by using DNA gel electrophoresis and TUNEL assay. At the same time, an increase in Fas(CD95/Apo-1) protein expression in splenocytes was also observed. These effects were significantly abolished by either chemical sympathectomy or beta-adrenergic receptor antagonist propranolol. The data clearly revealed that the sympathetic nervous system especially beta-adrenergic receptors was involved in surgical trauma-induced immune alterations via a mechanism of apoptotic cell death.

Role of phospholipase D2 in anti-apoptotic signaling through increased expressions of Bcl-2 and Bcl-xL

We have previously reported that Fas-resistant A20 cells (FasR) have phospholipase D (PLD) activity upregulated by endogenous PLD2 overexpression. In the present study, we investigated how overexpressed PLD2 in FasR could generate survival signals by regulating the protein levels of anti-apoptotic Bcl-2 and Bcl-xL. To confirm the effect of PLD2 on Bcl-2 protein levels, we transfected PLD2 into wild-type murine B lymphoma A20 cells. The transfected cells showed markedly the increases in Bcl-2 and Bcl-xL protein levels, and became resistant to Fas-induced apoptosis, similar to FasR. Treatment of wild-type A20 cells with phosphatidic acid (PA), the metabolic end product of PLD2 derived from phosphatidylcholin, markedly increased levels of anti-apoptotic Bcl-2 and Bcl-xL proteins. Moreover, PA-induced expressions of Bcl-2 and Bcl-xL were enhanced by propranolol, an inhibitor of PA phospholydrolase (PAP), whereas completely blocked by mepacrine, an inhibitor of phospholipase A(2) (PLA(2)), suggesting that PLA(2) metabolite of PA is responsible for the increases in Bcl-2 and Bcl-xL protein levels. We further confirmed the involvement of arachidonic acid (AA) in PA-induced survival signals by showing that 1,2-dipalmitoyl-sn-glycero-3-phosphate (DPPA), PA without AA, was unable to increase Bcl-2 and Bcl-xL proteins. Moreover, PA notably increased cyclooxygenase (COX)-2 protein expression, and PA-induced expression of both Bcl-2 and Bcl-xL was inhibited by NS-398, a specific inhibitor of COX-2. Taken together, these findings demonstrate that PA generated by PLD2 plays an important role in cell survival during Fas-mediated apoptosis through the increased Bcl-2 and Bcl-xL protein levels which resulted from PLA(2) and AA-COX2 pathway.