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Substance P and beta-endorphin mediate electro-acupuncture induced analgesia in mouse cancer pain model.

Lee HJ, Lee JH, Lee EO, Lee HJ, Kim KH, Kim SH, Lee KS, Jung HJ, Kim SH - J. Exp. Clin. Cancer Res. (2009)

Bottom Line: Opioid analgesics are generally used to combat the pain associated with cancerous conditions.These agents not only inhibit respiratory function and cause constipation, but also induce other significant side effects such as addiction and tolerance, all of which further contribute to a reduced quality of life for cancer patients.It also indicated that EA treatment could be used as an alternative therapeutic method for cancer pain due to a consequent decrease in substance P and increase in beta-endorphin levels.

View Article: PubMed Central - HTML - PubMed

Affiliation: College of Oriental Medicine, Kyung-Hee University, Seoul 130-701, South Korea. strong79@khu.ac.kr

ABSTRACT

Background: Opioid analgesics are generally used to combat the pain associated with cancerous conditions. These agents not only inhibit respiratory function and cause constipation, but also induce other significant side effects such as addiction and tolerance, all of which further contribute to a reduced quality of life for cancer patients. Thus, in the present study, the effects of electro-acupuncture treatment (EA) on mechanical allodynia were examined in a cancer pain mouse model.

Methods: In order to produce a neuropathic cancer pain model, S-180 sarcoma cells were inoculated around the sciatic nerve of left legs of Balb/c mice. Magnetic Resonance Imaging (MRI) scanning confirmed the mass of S-180 cancer cells embedded around the sciatic nerve. Mechanical allodynia was most consistently induced in the mouse sarcoma cell line S-180 (2 x 10(6)sarcoma cells)-treated group compared to all the other groups studied. EA stimulation (2 Hz) was administered daily to ST36 (Zusanli) of S-180 bearing mice for 30 min for 9 days after S-180 inoculation.

Results: EA treatment significantly prolonged paw withdrawal latency from 5 days after inoculation. It also shortened the cumulative lifting duration from 7 days after inoculation, compared to the tumor control. Also, the overexpression of pain peptide substance P in the dorsal horn of the spinal cord was significantly decreased in the EA-treated group compared to the tumor control on Day 9 post inoculation. Furthermore, EA treatment effectively increased the concentration of beta-endorphin in blood and brain samples of the mice to a greater extent than that of the tumor control as well as the normal group. The concentration of beta-endorphin for EA treatment group increased by 51.457% in the blood and 12.6% in the brain respectively, compared to the tumor control group.

Conclusion: The findings of this study suggest that a S-180 cancer pain model is useful as a consistent and short time animal model. It also indicated that EA treatment could be used as an alternative therapeutic method for cancer pain due to a consequent decrease in substance P and increase in beta-endorphin levels.

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A: Representative photographs of a coronal section showing SP expression in the spinal cord. Photographs (200 ×) illustrate SP immunoreactive neurons in the mouse superficial dorsal horn (SDH) of L3–5 levels. (a) Control, (b) Tumor control, (c) EA treated group. Arrows indicate SP positive cells. B&C: EA treatment increased the level of β-endorphin in blood and brain compared to untreated tumor control. B: level of β-endorphin in blood C: level of β-endorphin in brain. Values of β-endorphin are expressed as means ± SE. Different superscripts(a, b, c) indicate p < 0.05 statistical significance between groups using ANOVA test-Turkey's procedure.
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Figure 4: A: Representative photographs of a coronal section showing SP expression in the spinal cord. Photographs (200 ×) illustrate SP immunoreactive neurons in the mouse superficial dorsal horn (SDH) of L3–5 levels. (a) Control, (b) Tumor control, (c) EA treated group. Arrows indicate SP positive cells. B&C: EA treatment increased the level of β-endorphin in blood and brain compared to untreated tumor control. B: level of β-endorphin in blood C: level of β-endorphin in brain. Values of β-endorphin are expressed as means ± SE. Different superscripts(a, b, c) indicate p < 0.05 statistical significance between groups using ANOVA test-Turkey's procedure.

Mentions: Nine days after inoculation, immunohistochemistry was performed using antibodies against substance P, in sections of spinal cord dorsal horn of mice. As shown in Fig. 4A, substance P was overexpressed in the tumor control group compared to that of the normal control, suggesting that the tumor mass could activate neuropathic pain-related proteins. On the contrary, EA treatment for 9 days effectively reduced the expression of pain peptide substance P in the dorsal horn section of the spinal cord of mice compared to the untreated tumor control group. To elucidate its analgesic mechanism, the levels of β-endorphin in blood and brain tissues of mice were analyzed after EA treatment. As shown in Fig. 4B, the level of β-endorphin in blood samples of the tumor control group was significantly increased up to 2.8754 ± 0.0278 ng/mL compared to that of the normal group, 1.3236 ± 0.0041. On the contrary, EA treatment significantly increased the β-endorphin levels up to 4.355 ± 0.2972 ng/mL more than the tumor control group, 2.8754 ± 0.0278 ng/mL. Consistently, as shown in Fig. 4C, the level of β-endorphin in the brain tissues of mice within the tumor control group was significantly increased up to 4.0115 ± 0.3848 ng/mL compared to that of the normal group, 2.668 ± 1.069 ng/mL. In contrast, EA treatment significantly increased the level of β-endorphin up to 9.0847 ± 0.5901 ng/mL more than that of the tumor control group, 4.0115 ± 0.3848 ng/mL.


Substance P and beta-endorphin mediate electro-acupuncture induced analgesia in mouse cancer pain model.

Lee HJ, Lee JH, Lee EO, Lee HJ, Kim KH, Kim SH, Lee KS, Jung HJ, Kim SH - J. Exp. Clin. Cancer Res. (2009)

A: Representative photographs of a coronal section showing SP expression in the spinal cord. Photographs (200 ×) illustrate SP immunoreactive neurons in the mouse superficial dorsal horn (SDH) of L3–5 levels. (a) Control, (b) Tumor control, (c) EA treated group. Arrows indicate SP positive cells. B&C: EA treatment increased the level of β-endorphin in blood and brain compared to untreated tumor control. B: level of β-endorphin in blood C: level of β-endorphin in brain. Values of β-endorphin are expressed as means ± SE. Different superscripts(a, b, c) indicate p < 0.05 statistical significance between groups using ANOVA test-Turkey's procedure.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2724388&req=5

Figure 4: A: Representative photographs of a coronal section showing SP expression in the spinal cord. Photographs (200 ×) illustrate SP immunoreactive neurons in the mouse superficial dorsal horn (SDH) of L3–5 levels. (a) Control, (b) Tumor control, (c) EA treated group. Arrows indicate SP positive cells. B&C: EA treatment increased the level of β-endorphin in blood and brain compared to untreated tumor control. B: level of β-endorphin in blood C: level of β-endorphin in brain. Values of β-endorphin are expressed as means ± SE. Different superscripts(a, b, c) indicate p < 0.05 statistical significance between groups using ANOVA test-Turkey's procedure.
Mentions: Nine days after inoculation, immunohistochemistry was performed using antibodies against substance P, in sections of spinal cord dorsal horn of mice. As shown in Fig. 4A, substance P was overexpressed in the tumor control group compared to that of the normal control, suggesting that the tumor mass could activate neuropathic pain-related proteins. On the contrary, EA treatment for 9 days effectively reduced the expression of pain peptide substance P in the dorsal horn section of the spinal cord of mice compared to the untreated tumor control group. To elucidate its analgesic mechanism, the levels of β-endorphin in blood and brain tissues of mice were analyzed after EA treatment. As shown in Fig. 4B, the level of β-endorphin in blood samples of the tumor control group was significantly increased up to 2.8754 ± 0.0278 ng/mL compared to that of the normal group, 1.3236 ± 0.0041. On the contrary, EA treatment significantly increased the β-endorphin levels up to 4.355 ± 0.2972 ng/mL more than the tumor control group, 2.8754 ± 0.0278 ng/mL. Consistently, as shown in Fig. 4C, the level of β-endorphin in the brain tissues of mice within the tumor control group was significantly increased up to 4.0115 ± 0.3848 ng/mL compared to that of the normal group, 2.668 ± 1.069 ng/mL. In contrast, EA treatment significantly increased the level of β-endorphin up to 9.0847 ± 0.5901 ng/mL more than that of the tumor control group, 4.0115 ± 0.3848 ng/mL.

Bottom Line: Opioid analgesics are generally used to combat the pain associated with cancerous conditions.These agents not only inhibit respiratory function and cause constipation, but also induce other significant side effects such as addiction and tolerance, all of which further contribute to a reduced quality of life for cancer patients.It also indicated that EA treatment could be used as an alternative therapeutic method for cancer pain due to a consequent decrease in substance P and increase in beta-endorphin levels.

View Article: PubMed Central - HTML - PubMed

Affiliation: College of Oriental Medicine, Kyung-Hee University, Seoul 130-701, South Korea. strong79@khu.ac.kr

ABSTRACT

Background: Opioid analgesics are generally used to combat the pain associated with cancerous conditions. These agents not only inhibit respiratory function and cause constipation, but also induce other significant side effects such as addiction and tolerance, all of which further contribute to a reduced quality of life for cancer patients. Thus, in the present study, the effects of electro-acupuncture treatment (EA) on mechanical allodynia were examined in a cancer pain mouse model.

Methods: In order to produce a neuropathic cancer pain model, S-180 sarcoma cells were inoculated around the sciatic nerve of left legs of Balb/c mice. Magnetic Resonance Imaging (MRI) scanning confirmed the mass of S-180 cancer cells embedded around the sciatic nerve. Mechanical allodynia was most consistently induced in the mouse sarcoma cell line S-180 (2 x 10(6)sarcoma cells)-treated group compared to all the other groups studied. EA stimulation (2 Hz) was administered daily to ST36 (Zusanli) of S-180 bearing mice for 30 min for 9 days after S-180 inoculation.

Results: EA treatment significantly prolonged paw withdrawal latency from 5 days after inoculation. It also shortened the cumulative lifting duration from 7 days after inoculation, compared to the tumor control. Also, the overexpression of pain peptide substance P in the dorsal horn of the spinal cord was significantly decreased in the EA-treated group compared to the tumor control on Day 9 post inoculation. Furthermore, EA treatment effectively increased the concentration of beta-endorphin in blood and brain samples of the mice to a greater extent than that of the tumor control as well as the normal group. The concentration of beta-endorphin for EA treatment group increased by 51.457% in the blood and 12.6% in the brain respectively, compared to the tumor control group.

Conclusion: The findings of this study suggest that a S-180 cancer pain model is useful as a consistent and short time animal model. It also indicated that EA treatment could be used as an alternative therapeutic method for cancer pain due to a consequent decrease in substance P and increase in beta-endorphin levels.

Show MeSH
Related in: MedlinePlus