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The Antinociceptive Effect of Light-Emitting Diode Irradiation on Incised Wounds Is Correlated with Changes in Cyclooxygenase 2 Activity, Prostaglandin E2, and Proinflammatory Cytokines

View Article: PubMed Central - PubMed

ABSTRACT

Background. Light-emitting diode (LED) phototherapy has been reported to relieve pain and enhance tissue repair through several mechanisms. However, the analgesic effect of LED on incised wounds has never been examined. Objectives. We examined the analgesic effect of LED therapy on incision pain and the changes in cyclooxygenase 2 (COX-2), prostaglandin E2 (PGE2), and the proinflammatory cytokines interleukin 6 (IL-6), IL-1β, and tumor necrosis factor α (TNF-α). Methods. Rats received LED therapy on incised skin 6 days before incision (L-I group) or 6 days after incision (I-L group) or from 3 days before incision to 3 days after incision (L-I-L group). Behavioral tests and analysis of skin tissue were performed after LED therapy. Results. LED therapy attenuated the decrease in thermal withdrawal latency in all the irradiated groups and the decrease in the mechanical withdrawal threshold in the L-I group only. The expression levels of COX-2, PGE2, and IL-6 were significantly decreased in the three LED-treated groups, whereas IL-1β and TNF-α were significantly decreased only in the L-I group compared with their levels in the I groups (p < 0.05). Conclusions. LED therapy provides an analgesic effect and modifies the expression of COX-2, PGE2, and proinflammatory cytokines in incised skin.

No MeSH data available.


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Changes in mRNA levels of interleukin-6 (IL-6), IL-1β, and tumor necrosis factor α (TNF-α) after LED irradiation. Compared with the C groups, significant upregulation of IL-1β, IL-6, and TNF-α was noted in all the I groups (a, b, and c). Significantly decreased expression of IL-6 was noted in all the LED-irradiated groups compared with the incision only group (a). After LED irradiation, significantly decreased expression of IL-1β and TNF-α was noted only in the L-I group (b, c). C indicates LED irradiation for 6 days on sham skin incision in the paw contralateral to the LED-irradiated paw; I indicates incision only; L-I indicates LED irradiation for 6 days before skin incision; I-L indicates LED irradiation for 6 days after skin incision; L-I-L indicates LED irradiation from 3 days before skin incision to 3 days after skin incision. ∗p < 0.05 compared with the C and LED-irradiated groups; #p < 0.05 compared with the C groups. The values represent the means ± SD.
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fig4: Changes in mRNA levels of interleukin-6 (IL-6), IL-1β, and tumor necrosis factor α (TNF-α) after LED irradiation. Compared with the C groups, significant upregulation of IL-1β, IL-6, and TNF-α was noted in all the I groups (a, b, and c). Significantly decreased expression of IL-6 was noted in all the LED-irradiated groups compared with the incision only group (a). After LED irradiation, significantly decreased expression of IL-1β and TNF-α was noted only in the L-I group (b, c). C indicates LED irradiation for 6 days on sham skin incision in the paw contralateral to the LED-irradiated paw; I indicates incision only; L-I indicates LED irradiation for 6 days before skin incision; I-L indicates LED irradiation for 6 days after skin incision; L-I-L indicates LED irradiation from 3 days before skin incision to 3 days after skin incision. ∗p < 0.05 compared with the C and LED-irradiated groups; #p < 0.05 compared with the C groups. The values represent the means ± SD.

Mentions: The production of IL-6, COX-2, PGE2, IL-1β, and TNF-α from skin tissue in response to incision and the inhibitory effects of LED irradiation are shown in Figures 3 and 4. Compared with the C groups, significant upregulation of COX-2, PGE2, IL-6, IL-1β, and TNF-α was noted. The expression levels of COX-2, PGE2, and IL-6 were significantly decreased in the LED-treated groups compared with those in groups I-3 h, I-3 d, and I-6 d (p < 0.05) (Figures 3(a), 3(b), 3(c), 3(d), and 4(a)). IL-1β and TNF-α were significantly decreased in the L-I group compared with their levels in group I-3 h (p < 0.05) (Figures 4(b) and 4(c)). However, compared with the I-6 d and I-3 d groups, in the I-L and L-I-L groups, no significant differences in the expression of IL-1β or TNF-α were noted (Figures 4(b) and 4(c)).


The Antinociceptive Effect of Light-Emitting Diode Irradiation on Incised Wounds Is Correlated with Changes in Cyclooxygenase 2 Activity, Prostaglandin E2, and Proinflammatory Cytokines
Changes in mRNA levels of interleukin-6 (IL-6), IL-1β, and tumor necrosis factor α (TNF-α) after LED irradiation. Compared with the C groups, significant upregulation of IL-1β, IL-6, and TNF-α was noted in all the I groups (a, b, and c). Significantly decreased expression of IL-6 was noted in all the LED-irradiated groups compared with the incision only group (a). After LED irradiation, significantly decreased expression of IL-1β and TNF-α was noted only in the L-I group (b, c). C indicates LED irradiation for 6 days on sham skin incision in the paw contralateral to the LED-irradiated paw; I indicates incision only; L-I indicates LED irradiation for 6 days before skin incision; I-L indicates LED irradiation for 6 days after skin incision; L-I-L indicates LED irradiation from 3 days before skin incision to 3 days after skin incision. ∗p < 0.05 compared with the C and LED-irradiated groups; #p < 0.05 compared with the C groups. The values represent the means ± SD.
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fig4: Changes in mRNA levels of interleukin-6 (IL-6), IL-1β, and tumor necrosis factor α (TNF-α) after LED irradiation. Compared with the C groups, significant upregulation of IL-1β, IL-6, and TNF-α was noted in all the I groups (a, b, and c). Significantly decreased expression of IL-6 was noted in all the LED-irradiated groups compared with the incision only group (a). After LED irradiation, significantly decreased expression of IL-1β and TNF-α was noted only in the L-I group (b, c). C indicates LED irradiation for 6 days on sham skin incision in the paw contralateral to the LED-irradiated paw; I indicates incision only; L-I indicates LED irradiation for 6 days before skin incision; I-L indicates LED irradiation for 6 days after skin incision; L-I-L indicates LED irradiation from 3 days before skin incision to 3 days after skin incision. ∗p < 0.05 compared with the C and LED-irradiated groups; #p < 0.05 compared with the C groups. The values represent the means ± SD.
Mentions: The production of IL-6, COX-2, PGE2, IL-1β, and TNF-α from skin tissue in response to incision and the inhibitory effects of LED irradiation are shown in Figures 3 and 4. Compared with the C groups, significant upregulation of COX-2, PGE2, IL-6, IL-1β, and TNF-α was noted. The expression levels of COX-2, PGE2, and IL-6 were significantly decreased in the LED-treated groups compared with those in groups I-3 h, I-3 d, and I-6 d (p < 0.05) (Figures 3(a), 3(b), 3(c), 3(d), and 4(a)). IL-1β and TNF-α were significantly decreased in the L-I group compared with their levels in group I-3 h (p < 0.05) (Figures 4(b) and 4(c)). However, compared with the I-6 d and I-3 d groups, in the I-L and L-I-L groups, no significant differences in the expression of IL-1β or TNF-α were noted (Figures 4(b) and 4(c)).

View Article: PubMed Central - PubMed

ABSTRACT

Background. Light-emitting diode (LED) phototherapy has been reported to relieve pain and enhance tissue repair through several mechanisms. However, the analgesic effect of LED on incised wounds has never been examined. Objectives. We examined the analgesic effect of LED therapy on incision pain and the changes in cyclooxygenase 2 (COX-2), prostaglandin E2 (PGE2), and the proinflammatory cytokines interleukin 6 (IL-6), IL-1&beta;, and tumor necrosis factor &alpha; (TNF-&alpha;). Methods. Rats received LED therapy on incised skin 6 days before incision (L-I group) or 6 days after incision (I-L group) or from 3 days before incision to 3 days after incision (L-I-L group). Behavioral tests and analysis of skin tissue were performed after LED therapy. Results. LED therapy attenuated the decrease in thermal withdrawal latency in all the irradiated groups and the decrease in the mechanical withdrawal threshold in the L-I group only. The expression levels of COX-2, PGE2, and IL-6 were significantly decreased in the three LED-treated groups, whereas IL-1&beta; and TNF-&alpha; were significantly decreased only in the L-I group compared with their levels in the I groups (p &lt; 0.05). Conclusions. LED therapy provides an analgesic effect and modifies the expression of COX-2, PGE2, and proinflammatory cytokines in incised skin.

No MeSH data available.


Related in: MedlinePlus