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The influence of He-Ne laser on scar formation after trabeculectomy in rabbits
Jun Hu1, Gui-Gang Li, Hong Zhang
1Department of Ophthalmology, Tongji Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei Province, China.
Aim:
To investigate the influence of He-Ne lasers on scar formation in the filtration canal after trabeculectomy in a rabbit model, as well as to explore the mechanisms for preventing scar formation when using He-Ne lasers in vivo.
Methods:
Experiment 1: Four groups were established (four eyes in each group). In 12 eyes, the upper nasal limbus area next to the upper rectus muscle received 10 minutes of He-Ne laser irradiation (100, 150, 200mW/cm(2); 60, 90, 120J/cm(2)) every day for three days. Four eyes served as controls. Twenty-four hours after the final irradiation, the rabbits were sacrificed and the irradiated tissue was excised, fixed with paraformaldehyde and tested for proliferating cell nuclear antigen (PCNA), connective tissue growth factor (CTGF) and apoptosis (TUNEL). Experiment 2: Forty-two rabbits were randomly divided into two groups and standard trabeculectomy was performed in the right eyes either after 200mW/cm(2) He-Ne laser irradiation or not in the filtration area. The expression of PCNA and CTGF, apoptosis and collagen density in the filtration area were tested on the 7(th), 14(th) and 28(th) day after surgery.
Results:
Experiment 1: There were no more PCNA and CTGF positive cells in the He-Ne irradiation group than in the control group. No apoptotic cells were found in either group. Experiment 2: The expression of PCNA and CTGF was lower in the He-Ne irradiation group than in the control group on the 7(th) and 14(th) day after trabeculectomy surgery (P<0.05); no apoptotic cells were detected in either group. Collagen density was significantly lower in the He-Ne irradiation group than in the control group on the 14(th) and 28(th) day after surgery (P<0.05).
Conclusion:
Pretreating the filtration area with 200mW/cm(2) (120J/cm(2)) of He-Ne laser irradiation may be helpful in preventing scar formation after trabeculectomy, possibly due to the downregulation of the expression of PCNA, CTGF and collagen synthesis in fibroblasts.
Insights
Helium-neon (He-Ne) laser pretreatment may prevent scar formation after trabeculectomy by reducing key proteins like proliferating cell nuclear antigen (PCNA) and connective tissue growth factor (CTGF). This approach shows promise in glaucoma surgery by potentially downregulating fibroblast activity and collagen synthesis.
Area of Science:
- Ophthalmology
- Biomedical Engineering
- Regenerative Medicine
Background:
- Trabeculectomy is a surgical procedure to treat glaucoma by creating a new drainage channel for aqueous humor.
- Scar formation in the filtration area is a major cause of surgical failure after trabeculectomy.
- Identifying methods to prevent post-surgical scarring is crucial for improving long-term surgical outcomes.
Purpose of the Study:
- To evaluate the efficacy of Helium-Neon (He-Ne) laser irradiation in preventing scar tissue formation in the filtration canal post-trabeculectomy.
- To investigate the underlying mechanisms by which He-Ne laser influences scar formation in vivo.
Main Methods:
- Rabbits underwent He-Ne laser irradiation (200mW/cm(2)) on the filtration area before or after trabeculectomy.
- Tissue analysis included assessments for proliferating cell nuclear antigen (PCNA), connective tissue growth factor (CTGF), apoptosis, and collagen density.
- Expression levels and cellular changes were evaluated at various time points post-surgery.
Main Results:
- He-Ne laser irradiation did not increase PCNA, CTGF, or apoptotic cells in preliminary tests.
- Post-trabeculectomy, He-Ne laser treated eyes showed significantly lower PCNA and CTGF expression on days 7 and 14.
- Collagen density was notably reduced in He-Ne laser treated eyes on days 14 and 28 compared to controls.
Conclusions:
- Pretreatment with He-Ne laser (200mW/cm(2), 120J/cm(2)) appears to be a promising strategy for inhibiting scar formation after trabeculectomy.
- The mechanism likely involves the downregulation of PCNA, CTGF expression, and subsequent collagen synthesis in fibroblasts.
- He-Ne laser therapy may offer a novel approach to enhance the success rate of glaucoma filtration surgery.
