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Effects of low level laser treatment on the survival of axotomized retinal ganglion cells in adult Hamsters.

So KF, Leung MC, Cui Q - Neural Regen Res (2014)

Bottom Line: Injury to axons close to the neuronal bodies in the mammalian central nervous system causes a large proportion of parenting neurons to degenerate.We also found that single dose and early commencement of laser irradiation were important in protecting retinal ganglion cells following optic nerve axotomy.These findings thus convincingly show that appropriate laser treatment may be neuroprotective to retinal ganglion cells.

View Article: PubMed Central - PubMed

Affiliation: GHM Institute of CNS Regeneration, and Guangdong Key Laboratory of Brain Function and Diseases, Jinan University, Guangzhou, Guangdong Province, China ; Department of Anatomy, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China ; Department of Ophthalmology, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China.

ABSTRACT
Injury to axons close to the neuronal bodies in the mammalian central nervous system causes a large proportion of parenting neurons to degenerate. It is known that optic nerve transection close to the eye in rodents leads to a loss of about half of retinal ganglion cells in 1 week and about 90% in 2 weeks. Using low level laser treatment in the present study, we demonstrated that treatment with helium-neon (660 nm) laser with 15 mW power could delay retinal ganglion cell death after optic nerve axotomy in adult hamsters. The effect was most apparent in the first week with a short period of treatment time (5 minutes) in which 65-66% of retinal ganglion cells survived the optic nerve axotomy whereas 45-47% of retinal ganglion cells did so in optic nerve axotomy controls. We also found that single dose and early commencement of laser irradiation were important in protecting retinal ganglion cells following optic nerve axotomy. These findings thus convincingly show that appropriate laser treatment may be neuroprotective to retinal ganglion cells.

No MeSH data available.


Related in: MedlinePlus

Effect of single dose laser irradiation treatment (1 day) on the day of optic nerve injury compared with 7 consecutive treatment days (7 days).The average numbers of the granular blue-labeled retinal ganglion cells (RGCs) in the laser groups with single dose laser irradiation are not statistically different from those in the corresponding groups with 7 consecutive days of laser irradiation (P > 0.05), but both 1-minute (min) and 5 min groups irrespective of single dose or 7 consecutive days of laser treatment are neuroprotective (P < 0.001). Data are expressed as the mean ± SD. ***P < 0.001 (one-way analysis of variance followed by Bonferroni multiple comparison test).
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Figure 4: Effect of single dose laser irradiation treatment (1 day) on the day of optic nerve injury compared with 7 consecutive treatment days (7 days).The average numbers of the granular blue-labeled retinal ganglion cells (RGCs) in the laser groups with single dose laser irradiation are not statistically different from those in the corresponding groups with 7 consecutive days of laser irradiation (P > 0.05), but both 1-minute (min) and 5 min groups irrespective of single dose or 7 consecutive days of laser treatment are neuroprotective (P < 0.001). Data are expressed as the mean ± SD. ***P < 0.001 (one-way analysis of variance followed by Bonferroni multiple comparison test).

Mentions: Since prolonged laser irradiation did not appear to have a better action on RGC survival, we next examined the effect of single dose laser treatment on RGC viability. As Figure 4 shows, single dose of low level laser irradiation rendered similar neuroprotective effects to the 7 consecutive day treatment regimes, and there were no statistically significant difference between single dose and 7-day treatment of 1-, 5- and 10-minute groups (Figure 4). The average numbers of surviving RGCs in a single dose of 1- and 5-minute laser treatment groups were 51,257 ± 2,144/retina (n = 6) and 54,759 ± 5,895/retina (n = 5), respectively; both values were significantly (P < 0.001) higher than the axotomy control (Figure 4). Similar to what was observed in 7 consecutive day treatment group, 10-minute laser irradiation exerted poor neuroprotective effect, and the average number of GB-labeled RGCs was 42,580 ± 1,490/retina (n = 5). This value was no longer significantly higher than the axotomy control. These data indicate that a single dose of laser treatment for a short time duration (1–5 minutes) renders a similar neuroprotective effect on RGCs as 7 days of laser irradiation treatment.


Effects of low level laser treatment on the survival of axotomized retinal ganglion cells in adult Hamsters.

So KF, Leung MC, Cui Q - Neural Regen Res (2014)

Effect of single dose laser irradiation treatment (1 day) on the day of optic nerve injury compared with 7 consecutive treatment days (7 days).The average numbers of the granular blue-labeled retinal ganglion cells (RGCs) in the laser groups with single dose laser irradiation are not statistically different from those in the corresponding groups with 7 consecutive days of laser irradiation (P > 0.05), but both 1-minute (min) and 5 min groups irrespective of single dose or 7 consecutive days of laser treatment are neuroprotective (P < 0.001). Data are expressed as the mean ± SD. ***P < 0.001 (one-way analysis of variance followed by Bonferroni multiple comparison test).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4281419&req=5

Figure 4: Effect of single dose laser irradiation treatment (1 day) on the day of optic nerve injury compared with 7 consecutive treatment days (7 days).The average numbers of the granular blue-labeled retinal ganglion cells (RGCs) in the laser groups with single dose laser irradiation are not statistically different from those in the corresponding groups with 7 consecutive days of laser irradiation (P > 0.05), but both 1-minute (min) and 5 min groups irrespective of single dose or 7 consecutive days of laser treatment are neuroprotective (P < 0.001). Data are expressed as the mean ± SD. ***P < 0.001 (one-way analysis of variance followed by Bonferroni multiple comparison test).
Mentions: Since prolonged laser irradiation did not appear to have a better action on RGC survival, we next examined the effect of single dose laser treatment on RGC viability. As Figure 4 shows, single dose of low level laser irradiation rendered similar neuroprotective effects to the 7 consecutive day treatment regimes, and there were no statistically significant difference between single dose and 7-day treatment of 1-, 5- and 10-minute groups (Figure 4). The average numbers of surviving RGCs in a single dose of 1- and 5-minute laser treatment groups were 51,257 ± 2,144/retina (n = 6) and 54,759 ± 5,895/retina (n = 5), respectively; both values were significantly (P < 0.001) higher than the axotomy control (Figure 4). Similar to what was observed in 7 consecutive day treatment group, 10-minute laser irradiation exerted poor neuroprotective effect, and the average number of GB-labeled RGCs was 42,580 ± 1,490/retina (n = 5). This value was no longer significantly higher than the axotomy control. These data indicate that a single dose of laser treatment for a short time duration (1–5 minutes) renders a similar neuroprotective effect on RGCs as 7 days of laser irradiation treatment.

Bottom Line: Injury to axons close to the neuronal bodies in the mammalian central nervous system causes a large proportion of parenting neurons to degenerate.We also found that single dose and early commencement of laser irradiation were important in protecting retinal ganglion cells following optic nerve axotomy.These findings thus convincingly show that appropriate laser treatment may be neuroprotective to retinal ganglion cells.

View Article: PubMed Central - PubMed

Affiliation: GHM Institute of CNS Regeneration, and Guangdong Key Laboratory of Brain Function and Diseases, Jinan University, Guangzhou, Guangdong Province, China ; Department of Anatomy, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China ; Department of Ophthalmology, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China.

ABSTRACT
Injury to axons close to the neuronal bodies in the mammalian central nervous system causes a large proportion of parenting neurons to degenerate. It is known that optic nerve transection close to the eye in rodents leads to a loss of about half of retinal ganglion cells in 1 week and about 90% in 2 weeks. Using low level laser treatment in the present study, we demonstrated that treatment with helium-neon (660 nm) laser with 15 mW power could delay retinal ganglion cell death after optic nerve axotomy in adult hamsters. The effect was most apparent in the first week with a short period of treatment time (5 minutes) in which 65-66% of retinal ganglion cells survived the optic nerve axotomy whereas 45-47% of retinal ganglion cells did so in optic nerve axotomy controls. We also found that single dose and early commencement of laser irradiation were important in protecting retinal ganglion cells following optic nerve axotomy. These findings thus convincingly show that appropriate laser treatment may be neuroprotective to retinal ganglion cells.

No MeSH data available.


Related in: MedlinePlus