Effects of low energy laser therapy and herbal medication on ligament healing in rats

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Effects of low energy laser therapy and herbal medication on ligament healing in rats


Author: Fung, Tak-chee Dicky
Title: Effects of low energy laser therapy and herbal medication on ligament healing in rats
Degree: Ph.D.
Year: 2003
Subject: Hong Kong Polytechnic University -- Dissertations
Ligaments -- Wounds and injuries -- Radiotherapy
Connective tissues -- Diseases -- Radiotherapy
Department: Dept. of Rehabilitation Sciences
Pages: xxii, 250 leaves : ill. (some col.) ; 30 cm
Language: English
InnoPac Record: http://library.polyu.edu.hk/record=b1706026
URI: http://theses.lib.polyu.edu.hk/handle/200/917
Abstract: Low level laser therapy (LLLT) and herbal prescriptions have been used in the clinic for treatment of soft tissue injures. However, there is a lack of conclusive evidence supporting the use of these treatments for soft tissue injuries during the sub-acute and chronic stages of recovery. In light of this, the present series of studied were conducted in order to investigate the biomechanical and ultrastructural effects of gallium aluminum arsenide (GaAIAs) LLLT of dosages 31.6 and 63.2 Jcm-², and an external herbal remedy on injured rat medial collateral ligaments (MCLs) at 3 and 6 weeks post-injury. A total of 112 mature male Sprague-Dawley rats were tested. Eighty rats received surgical transection to their right MCLs and 32 rats received only skin wound to their right knee but no injury to the MCL served as sham operated controls. Thirty-two MCL injured rats were treated with LLLT for 7.5 minutes (n=16) or 15 minutes (n=16) at the time of surgery. Sixteen MCL-injured rats received a herbal plaster treatment. The remaining MCL-injured animals served as LLLT controls (n=16) and herb controls (n=16). All animals were tested at 3 weeks (n=56) or 6 weeks (n=56) after operation. The analyses included tissue biomechanical strength and ultrastructural collagen morphology. Results of biomechanical findings were analyzed using two-way analysis of variance (ANOVA), while that of ultrastructural morphology were analyzed with kruskal-Wallis test. For the biomechanical findings, all the LLLT-treated and herb-treated MCLs showed significantly higher ultimate tensile strength (UTS) and stiffness than the untreated controls (p < 0.01) at both testing periods. The UTS of both LLLT-treated groups and the stiffness of the herb-treated group were comparable to the sham operated groups at both testing periods. No significant difference was found in these biomechanical parameters between the two LLLT-treated groups. There was a significant increase in stiffness from 3 to 6 weeks post-injury (p < 0.05) in both dosage groups of the LLLT-treated animals. The stiffness of the herb-treated group was significantly higher than both LLLT-treated groups (p < 0.05) at both testing periods.
For the ultrastructural morphology studies, a total of 770,526 fibrils (about 13,700 fibrils per animal) were analyzed and it was found that the mean collagen fibril diameters in both the LLLT-treated and herb-treated groups were larger than the untreated controls (p < 0.001). Although the core mean collagen fibril diameters of the LLLT-treated and herb-treated groups were smaller than the sham groups (p < 0.001), the peripheral fibril sizes were comparable. From 3 to 6 weeks post-injury, the mass-averaged diameters of the core fibrils of the LLLT-treated and herb-treated groups approached the values of the sham groups. Most of the core fibrils in the LLLT-treated and herb-treated groups were large (about 200nm), whereas the collagen fibrils of the controls remained to be below 100nm throughout the studied period. These results demonstrated that both LLLT and the herbal remedy can restore UTS, stiffness and collagen fibril sizes from 3 to 6 weeks after complete transection injury of the MCL in rats. The herbal remedy is superior to LLLT in improving the structural stiffness of the scar. There is no further treatment effect when the LLLT dosage is increased from 31.6 to 63.2 Jcm-².

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