A neuroprotective herbal mixture inhibits caspase-3-independent apoptosis in retinal ganglion cells.

It was previously demonstrated that Menta-FX, a mixture of Panax quinquefolius L. (PQE), Ginkgo biloba (GBE), and Hypericum perforatum extracts (HPE), enhances retinal ganglion cell survival after axotomy. However, the mechanisms of neuroprotection remain unknown. The aim of this study is to elucidate the neuroprotective mechanisms of Menta-FX. Since PQE, GBE and HPE have all been observed to display anti-oxidative property, the involvement of anti-oxidation in Menta-FX's neuroprotective effect was investigated. Menta-FX lowered nitric oxide (NO) content in axotomized retinas without affecting nitric oxide synthase activity, suggesting that Menta-FX possibly exhibited a NO scavenging property. In addition, the effect of Menta-FX on the frequency of axotomy-induced nuclear fragmentation and caspase-3 activation was investigated. Menta-FX treatment significantly reduced nuclear fragmentation in axotomized retinas. Surprisingly, Menta-FX had no effect on caspase-3 activation, but selectively lowered caspase-3-independent nuclear fragmentation in axotomized retinal ganglion cells. In addition, inhibition of PI3K activity by intravitreal injection of wortmannin, a phosphoinositide-3 kinase (PI3K) inhibitor, completely abolished the neuroprotective effect of Menta-FX, indicating that Menta-FX's neuroprotective effect was PI3K-dependent. Data here suggest that Menta-FX displayed a PI3K-dependent, selective inhibition on a caspase-3-independent apoptotic pathway in axotomized RGCs, thus, highlighting the potential use of herbal remedies as neuroprotective agents for other neurodegenerative diseases.

The time effect of pressure on tissue viability: investigation using an experimental rat model.

An experimental rat model was used to investigate the time-pressure effect on tissue viability. External loading equivalent to 13.3 kPa (100 mm Hg) of pressure was applied to the greater trochanter and tibialis area of Sprague-Dawley rats using pneumatic indentors for duration of 6 hrs each day for 1 to 4 days. It was observed that postocclusive hyperemic responses were gradually increased at the trochanter throughout the 4 days of loading, whereas for the tibia there was a significant increase (P = 0.04) in postocclusive hyperemic flow between Days 2 and 3. In histologic evaluations, cutaneous tissue damage was observed at the trochanter area but not at the tibialis area after 2 consecutive days of load application. In contrast, degeneration of muscle cells characterized by numerous increases of nuclei occupying the central of the muscle fibers was observed after 2 days of load application at the tibialis. The situation was found to progress with time (P = 0.17). The presence of other histologic signs, including the internalization of peripherally located nuclei, replacement of muscle cells by fibrosis and adipose tissues, and the presence of pyknotic nuclei as well as karyorrhexis, confirmed that the affected tissues were damaged. These findings suggest that postocclusive hyperemia and the distress of tissues under loading could be closely related.

Mechanical effects of traction on lumbar intervertebral discs: A magnetic resonance imaging study.

BACKGROUND: Although traction has long been used for treating patients with low back pain (LBP), its effects are still inconclusive mainly because of limited high-quality evidence. OBJECTIVE: To provide evidence of the mechanism of traction on lumbar intervertebral discs. DESIGN: A quantitative approach with a repeated measurement protocol. METHOD: Nine participants (mean age = 22.1 ± 0.8 years) without any LBP history were recruited. Magnetic Resonance Images of the lumbar spine of each participant were recorded before and after 30 min of horizontal lying and directly after 30 min of horizontal traction of 42% body weight. The average, anterior, central, and posterior disc height and tilt angle of each lumbar disc and lumbar lordosis were measured. RESULTS: A significant increase in the average disc height for all lumbar discs, a significant reduction of lumbar lordosis and changes in tilt angle were observed after the application of 30 min of resting followed by 30 min of traction. A significant increase in the average disc height was observed only in lower lumbar discs after 30 min of traction. The increase in the posterior disc height was more apparent than that in the anterior disc height. CONCLUSIONS: Horizontal traction was evidently effective in increasing the disc height of lower lumbar levels, particularly in the posterior regions of the discs. Further evidence of the effects of traction of different modes, magnitudes, and durations on the change in disc height is required for proper control of traction applied to specific disc levels.

Effects of prolonged surface pressure on the skin blood flowmotions in anaesthetized rats--an assessment by spectral analysis of laser Doppler flowmetry signals.

The objective of this study is to assess the effect of prolonged surface compression on the skin blood flowmotion in rats using spectral analysis based on wavelets transform of the periodic oscillations of the cutaneous laser Doppler flowmetry (LDF) signal. An external pressure of 13.3 kPa (100 mmHg) was applied to the trochanter area and the distal lateral tibia of Sprague-Dawley rats via two specifically designed pneumatic indentors. The loading duration was 6 hours/day for 4 consecutive days. Five frequency intervals were identified (0.01-0.04 Hz, 0.04-0.15 Hz, 0.15-0.4 Hz, 0.4-2 Hz and 2-5 Hz) corresponding to endothelial related metabolic, neurogenic, myogenic, respiratory and cardiac origins. The absolute amplitude of oscillations of each particular frequency interval and the normalized amplitude were calculated for quantitative assessments. The results showed that (1) tissue compression following the above schedule induced significant decrease in the normalized amplitude in the frequency interval of 0.01-0.04 Hz both in the trochanter area (p < 0.001) and tibialis area (p = 0.023), (2) prolonged compression induced significant increase in the absolute amplitude (p = 0.004 for the trochanter area and p = 0.017 for the tibialis area) but significant decrease in the normalized amplitude (p = 0.023 for the trochanter area and p = 0.026 for the tibialis area) in the frequency interval of 0.15-0.4 Hz, and (3) at the tibialis area, the flowmotion amplitude (frequency interval 0.15-0.4 Hz) measured prior to the daily tissue compression schedule was found to be significantly higher on day 4 than the measurements obtained on day 1. However, this finding was not observed at the trochanter area. Our results suggested that prolonged compression might induce endothelial damage and affect the endothelial related metabolic activities.

Therapeutic ultrasound enhances medial collateral ligament repair in rats.

The purpose of this study was to evaluate the effects of therapeutic ultrasound (US) on medial collateral ligament healing. A total of 36 3-month-old male Sprague-Dawley rats with transected medial collateral ligaments were studied. Subjects were given 5-min pulsed US therapy (duty cycle; one application in 4 ms; 1:4) daily with different durations (1 day, 5 days and 10 days) and intensities (0, 0.5 and 2.3 W/cm2). After each treatment, the level of transforming growth factor beta-1 (TGF-beta1) of the ligament was measured. TGF-beta1 was not detected in the 1-day group. In the 5-day and 10-day groups, the levels of TGF-beta1 were significantly up-regulated in the high-dose subgroup (p < 0.05). The 10-day group also registered a significantly higher expression of TGF-beta1 than did the 5-day group (p < 0.05). The present findings suggest that pulsed US therapy may enhance ligament repair by up-regulating the extent of TGF-beta1 in a high-dose application. Long-term treatment with this therapy could obtain further improvement.

The Effect of Acupressure on Agitation and Salivary Cortisol in People with Dementia: A Pilot Study.

OBJECTIVES: This study aimed to identify the acupressure effect over time, compare the efficacy in different dosages, and identify feasibility issues with saliva sample collection and acupressure implementation in agitated nursing home residents with dementia. DESIGN: Time serial design with eight dosage-combination groups. SETTING: Three residential care homes (RCHs) in Hong Kong. PARTICIPANTS: Agitated RCH residents with dementia. INTERVENTIONS: Acupressure was performed for 9 minutes altogether on five acupoints: Fengchi (GB 20), Baihui (GV 20), Shenmen (HT 7), Niguan (PC 6), and Yingtang (EX-HN 3). Two frequencies (once and twice a day) and four durations (1, 2, 3, and 4 weeks) formed eight dosage combinations. OUTCOME MEASURES: The primary outcome was agitation, measured by the Cohen Mansfield Agitation Inventory. The secondary outcome was stress, measured by salivary cortisol. RESULTS: Twenty-four participants from three RCHs completed the study. Acupressure was successfully completed for 88% of total sessions, and 79.17% of participants completed more than 80% of expected sessions. The effect of acupressure on agitation onset was seen immediately at week 1 (p < 0.001), resurged at week 4 (p = 0.001), and was sustained until week 6 (p < 0.001). The effect on stress began immediately to a mild extent at week 1 (p = 0.011) and peaked at week 4 (p = 0.010). Acupressure was observed to show the largest effect when it was performed twice a day (p = 0.026) for 2 weeks (p = 0.005). Valid saliva samples were collected for 53.33% of participants. Hyposalivation caused this unsatisfactory yield of valid saliva samples. CONCLUSION: Acupressure can be conducted on agitated RCH residents with dementia, but low yield of saliva samples related to participants' hyposalivation is a problem. Preliminary findings suggest that acupressure is effective in reducing both agitation and stress. Its onset of effect was immediate, and the effect was sustained until 6 weeks after the intervention. The optimal dosage appears to be a course of acupressure twice a day for 2 weeks.

Electro-acupuncture potentiates the disulphide-reducing activities of thioredoxin system by increasing thioredoxin expression in ischemia-reperfused rat brains.

Reactive oxygen species can directly affect the conformation and activity of sulfhydryl-containing proteins by oxidation of their thiol moiety. During the process of ischemia-reperfusion, the thioredoxin (Trx) system (consisting of thioredoxin reductase (TR), Trx and NADPH) prevents susceptible proteins from this oxidative modification. Oxidative damage is one of the most damaging stress in ischemia. If oxidative stress could be minimized, the damage occurred will be minimized accordingly. We therefore investigated whether electroacupuncture (EA) treatment at Fengchi (GB20) or Zusanli (ST36) acupoints in post-ischemic rats could increase TR-related activities and Trx expression which would translate into maintaining the intact thiol moiety of susceptible proteins in the surrounding. Our results indicated that EA treatment at either acupoint increased the Trx expression in ischemic-reperfused brain tissues. Induced Trx expressed levels gradually increased from post-ischemia day 1 to day 4. Statistical analysis revealed that there was no observable difference in the effect of EA treatment at GB20 and ST36. Sham EA treatment did not induce any Trx expression. EA at either acupoint did not alter TR activities in both non-ischemic and ischemic-reperfused rat brains. Taken overall, our finding suggests that EA treatment at GB20 or ST36 could increase Trx expression which could minimize oxidative modifications of thiol groups of surrounding proteins.

Electroacupuncture provides a new approach to neuroprotection in rats with induced glaucoma.

OBJECTIVES: To investigate, using multifocal electroretinogram (mfERG), the effect of electroacupuncture (EA) on retinal function in rats with experimental glaucoma. DESIGN AND SUBJECTS: Glaucoma was induced in the right eyes of 15 adult female Sprague-Dawley rats by laser photocoagulation for three quarters of the perilimbal and episcleral vessels. The left eye of each rat was used as the control. The animals were divided into 3 groups: no treatment (non-EA control group), 2 Hz EA group, and 100 Hz EA group. EA treatment at different frequencies can produce different levels of analgesia and hence the effect of EA with different frequencies on glaucoma treatment was investigated. Both eyes of each rat in the EA experimental groups received 3 EA treatment sessions each week for 4 weeks. The retinal function was measured using mfERG after 4 weeks of EA treatment. RESULTS: There was no significant difference in the amplitude (both N1 trough and P1 peak) of mfERG firstorder kernel response between the treatment and control groups. In determining the waveform characteristics by the ratio of N1 amplitude to P1 amplitude (N/P ratio), obvious differences were found in the N/P ratio between the control eyes and the glaucoma eyes in the non-EA group and the 100 Hz EA treatment group, but similar values in the N/P ratio were observed between the control eyes and the glaucoma eyes in the 2 Hz EA treatment group. The waveform from the eyes with glaucoma was deformed in both the non-EA group and the 100 Hz EA group, but the waveform from the glaucomatous eye was preserved in the 2 Hz EA group. CONCLUSIONS: Application of EA at 2 Hz provides neuroprotection by preserving retinal function in rats with experimental glaucoma. Low frequency EA may be an alternative therapy in the treatment of glaucoma.

Electroacupuncture reduces the extent of lipid peroxidation by increasing superoxide dismutase and glutathione peroxidase activities in ischemic-reperfused rat brains.

Reactive oxygen species can be scavenged by superoxide dismutase (SOD) and glutathione peroxidase (GPx). During ischemia-reperfusion, the normal functioning of these antioxidant enzymes may be insufficient for the prevention of oxidant-induced peroxidation of membrane lipids and hence cerebral infarction. We therefore investigated whether electroacupuncture (EA) treatment at Fengchi points in post-ischemic rats could increase the antioxidant enzyme activities and thereby reduce the extent of lipid peroxidation. The results indicated that while EA did not alter the antioxidant enzyme activities in non-ischemic normal rat brains, ischemia-reperfusion caused significant increases in SOD and GPx activities. EA treatment further increased the antioxidant enzyme activities in ischemic-reperfused brain tissues, with a concomitant decrease in the extent of lipid peroxidation. Our finding suggests that EA treatment at Fengchi reduced the extent of lipid peroxidation in ischemic-reperfused rat brains, possibly by increasing the activities of SOD and GPx.

Effectiveness of multiple pre-ischemia electro-acupuncture on attenuating lipid peroxidation induced by cerebral ischemia in adult rats.

Free radicals induced by cerebral ischemia-reperfusion injury can trigger lipid peroxidation, leading to the production of malondialdehyde (MDA) and 4-hydroxy-2(E)-nonenal (4-HNE). Post-ischemia electroacupuncture (EA) therapy was able to reduce extent of lipid peroxidation. However, the effect of pre-ischemic EA therapy has not been reported. In this study, we aim to investigate the effectiveness of pre-ischemic EA therapy on lipid peroxidation in the rat ischemic injury model. Four groups of Sprague-Dawley rats were designed: Placebo group (without EA therapy), NA group (EA therapy on non-acupoint), GB20 group (EA therapy on Fengchi), and ST36 group (EA therapy on Zusanli). Half of each group (n = 6) received 30-minute EA therapy for 3 times and the other half group for 18 times before the occlusion of right middle cerebral artery. Right brains were taken for determination of concentration of MDA and the total of MDA plus 4-HNE. We found that multiple pre-ischemia EA therapy at either GB20 or ST36 can effectively reduce the amount of MDA produced after MCA occlusion. However, this reduction was not observed in the total amount of MDA and 4-HNE. In conclusion, pre-ischemia EA can partly regulate the lipid peroxidation in cerebral ischemia, where both GB20 and ST36 have a similar beneficial effectiveness.

Therapeutic ultrasound improves strength of achilles tendon repair in rats.

The purpose of this study was to evaluate the effects of therapeutic ultrasound on structural properties and functional performance of Achilles tendon healing. Thirty Sprague-Dawley rats with surgical hemitransected Achilles tendon were studied. Ten were treated daily with 1 MHz continuous ultrasound at 1.0 W/cm2 for 4 min, 11 at 2.0 W/cm2 for 4 min and nine served as control without treatment. Achilles functional index (AFI) was recorded preoperatively and on postoperative days 3, 10 and 30. On day 30, the rats were sacrificed and Achilles tendons were tested for load-relaxation, stiffness and ultimate tensile strength (UTS). Results showed that UTS of both low-dose (p=0.023) and high-dose (p=0.002) groups was significantly greater than in controls. No significant differences in AFI (p=0.179), load-relaxation (p=0.205) and stiffness (p=0.842) were found among groups. These findings suggested that both low- and high-dose therapeutic ultrasound accelerate the healing process of ruptured tendon.

The effects of electro-acupuncture and transcutaneous electrical nerve stimulation on patients with painful osteoarthritic knees: a randomized controlled trial with follow-up evaluation.

OBJECTIVES: To examine the relative effectiveness of electro-acupuncture (EA) and transcutaneous electrical nerve stimulation (TENS) in alleviating osteoarthritic (OA)-induced knee pain. DESIGN: Single-blinded, randomized controlled study. SUBJECTS: Twenty-four (24) subjects (23 women and 1 man), mean age 85, were recruited from eight subsidized Care & Attention Homes for the elderly. INTERVENTIONS: Subjects were randomly assigned to the EA, TENS, or control groups. Subjects in the EA group (n = 8) received low-frequency EA (2 Hz) on two acupuncture points (ST-35, Dubi and EX-LE-4, Neixiyan) of the painful knee for 20 minutes. Subjects in the TENS group (n = 8) received low-frequency TENS of 2 Hz and pulse width of 200 micros on the same acupuncture points for 20 minutes. In both treatment groups, electrical treatment was carried out for a total of eight sessions in 2 weeks. Eight subjects received osteoarthritic knee care and education only in a control group. All subjects were evaluated before the first treatment, after the last treatment, and at 2-week follow-up periods. RESULTS: After eight sessions of treatment, there was significant reduction of knee pain in both EA group and TENS group, as measured by the Numeric Rating Scale (NRS) of pain (p < 0.01). Prolonged analgesic effect was maintained in the EA and the TENS groups at a 2-week follow-up evaluation. The Timed Up-and-Go Test (TUGT) score of the EA group was significantly lower than that of the control group (p < 0.05), but such change was not observed in the TENS group. CONCLUSIONS: Both EA and TENS treatments were effective in reducing OA-induced knee pain. EA had the additional advantage of enhancing the TUGT results as opposed to TENS treatment or no treatment, which did not produce such corollary effect.

The use of electro-acupuncture in conjunction with exercise for the treatment of chronic low-back pain.

OBJECTIVES: To determine the effect of a series of electro-acupuncture (EA) treatment in conjunction with exercise on the pain, disability, and functional improvement scores of patients with chronic low-back pain (LBP). DESIGN: A blinded prospective randomized controlled study. SUBJECTS AND INTERVENTIONS: A total of 52 patients were randomly allocated to an exercise group (n = 26) or an exercise plus EA group (n = 26) and treated for 12 sessions. OUTCOME MEASURES: Numerical Rating Scale (NRS), Aberdeen LBP scale, lumbar spinal active range of movement (AROM), and the isokinetic strength were assessed by a blinded observer. Repeated measures analysis of variance (R-ANOVA) with factors of group and time was used to compare the outcomes between the two groups at baseline (before treatment), immediately after treatment, 1-month follow-up, and 3-month follow-up. The level of significance was set at p = 0.05. RESULTS: Significantly better scores in the NRS and Aberdeen LBP scale were found in the exercise plus EA group immediately after treatment and at 1-month follow-up. Higher scores were also seen at 3-month follow-up. No significant differences were observed in spinal AROM and isokinetic trunk concentric strength between the two groups at any stage of follow-up. CONCLUSIONS: This study provides additional data on the potential role of EA in the treatment of LBP, and indicates that the combination of EA and back exercise might be an effective option in the treatment of pain and disability associated with chronic LBP.

Comparison of the effectiveness between manual acupuncture and electro-acupuncture on patients with tennis elbow.

This is a single-blinded randomized controlled trial to compare the relative effectiveness between manual acupuncture (MA) and electro-acupuncture (EA) on the patients with chronic tennis elbow. Twenty patients recruited in the study were first introduced into control group for 2 weeks waiting period. Then, they were randomly assigned into either MA or EA group for acupuncture treatment. The acupuncture points of GB34 and ST38 were used in both treatment groups. In the MA group, the needle was retained for 20 minutes after the Deqi sensation obtained. In the EA group, electrical stimulation with 4 pulses/second frequency was applied and treatment lasted for 20 minutes. After 6 treatments within 2 weeks duration, significant differences were observed between groups favoring the electro-acupuncture in relation to pain relief (Pain visual analogue scale) and pain free hand grip strength (PFG). This study showed that electro-acupuncture is superior to manual acupuncture in treating patients with tennis elbow.

Treadmill pre-training ameliorates brain edema in ischemic stroke via down-regulation of aquaporin-4: an MRI study in rats.

OBJECTIVE: Treadmill pre-training can ameliorate blood brain barrier (BBB) dysfunction in ischemia-reperfusion injury, however, its role in ischemic brain edema remains unclear. This study assessed the neuroprotective effects induced by treadmill pre-training, particularly on brain edema in transient middle cerebral artery occluded model. METHODS: Transient middle cerebral artery occlusion to induce stroke was performed on rats after 2 weeks of treadmill pre-training. Magnetic resonance imaging (MRI) was used to evaluate the dynamic impairment of cerebral edema after ischemia-reperfusion injury. In addition, measurements of wet and dry brain weight, Evans Blue assay and Garcia scores were performed to investigate the cerebral water content, BBB permeability and neurologic deficit, respectively. Moreover, during ischemia-reperfusion injury, the expression of Aquaporin 4 (AQP4) was detected using immunofluorescence and Western bloting analyses. RESULTS: Treadmill pre-training improved the relative apparent diffusion coefficient (rADC) loss in the ipsilateral cortex and striatum at 1 hour and 2.5 hours after cerebral ischemia. In the treadmill pre-training group, T2W1 values of the ipsilateral cortex and striatum increased less at 7.5 hours, 1 day, and 2 days after stroke while the brain water content decreased at 2 days after ischemia. Regarding the BBB permeability, the semi-quantitative amount of contrast agent leakage of treadmill pre-training group significantly decreased. Less Evans Blue exudation was also observed in treadmill pre-training group at 2 days after stroke. In addition, treadmill pre-training mitigated the Garcia score deficits at 2 days after stroke. Immunofluorescence staining and Western blotting results showed a significant decrease in the expression of AQP4 after treadmill ischemia following pre-training. CONCLUSIONS: Treadmill pre-training may reduce cerebral edema and BBB dysfunction during cerebral ischemia/reperfusion injury via the down-regulation of AQP4.

Effects of Panax ginseng-containing herbal plasters on compressed intervertebral discs in an in vivo rat tail model.

BACKGROUND: Tienchi (Panax notoginseng) has been used in conservative treatments for back pain as a major ingredient of many herbal medicines. This study aims to investigate the effects of a herbal medicine containing tienchi on compressed intervertebral discs in rats. METHODS: Using an in vivo rat tail model, intervertebral disc compression was simulated in the caudal 8-9 discs of 25 rats by continuous static compression (11 N) for 2 weeks. An herbal medicine plaster (in which the major ingredient was tienchi) was externally applied to the compressed disc (n=9) for three weeks, and held in place by an adhesive bandage, in animals in the Chinese Medicine (CM) group. The effect of the bandage was evaluated in a separate placebo group (n=9), while no intervention with unrestricted motion was provided to rats in an additional control group (n=7). Disc structural properties were quantified by in vivo disc height measurement and in vitro morphological analysis. RESULTS: Disc height decreased after the application of compression (P < 0.001). The disc height decreased continuously in the control (P = 0.006) and placebo (P = 0.003) groups, but was maintained in the CM group (P = 0.494). No obvious differences in disc morphology were observed among the three groups (P = 0.896). CONCLUSION: The tienchi-containing herbal plaster had no significant effect on the morphology of compressed discs, but maintained disc height in rats.

Ultrastructural comparison of medial collateral ligament repair after single or multiple applications of GaAlAs laser in rats.

BACKGROUND AND OBJECTIVES: To examine single versus multiple applications of a gallium aluminum arsenide (GaAlAs) laser on the ultrastructural morphology of surgically injured medial collateral ligaments (MCLs) in rats. STUDY DESIGN/MATERIALS AND METHODS: Sixteen rats were studied with 12 receiving right MCL transection and 4 receiving sham injury. Group 1 (n = 4) received one session of laser (31.6 J/cm(2)) immediately after injury. Group 2 (n = 4) received 9 doses of transcutaneous laser (3.5 J/cm(2)). The controls (Group 3, n = 4) received one session of placebo laser, while the sham Group 4 (n = 4) received no treatment. Ultrastructural analyses were done with electron microscopy at 3 weeks. RESULTS: The mass-averaged diameters of collagen fibril in the core and periphery of MCLs treated with multiple laser were larger than the control and those with single laser treatment (P < 0.05). However, the sham injured group had larger fibrils than all other groups (P < 0.05). CONCLUSIONS: The repairing MCLs had smaller collagen fibrils than the sham injured ligaments. Multiple laser treatments enhanced the collagen growth in the repairing MCLs at 3 weeks after injury, which are superior to a single treatment with similar dosage.

Comparison of single and multiple applications of GaAlAs laser on rat medial collateral ligament repair.

BACKGROUND AND OBJECTIVES: To examine single versus multiple applications of the gallium aluminum arsenide (GaAlAs) laser on the healing of surgically injured medial collateral ligaments (MCLs) in rats. STUDY DESIGN/MATERIALS AND METHODS: Sixteen rats were studied, with 12 receiving surgical transection to their right MCL and 4 receiving a sham injury. Group 1 (n = 4) received a single dose of GaAlAs laser therapy (wavelength 660 nm, average power 8.8 mW, pulse 10 kHz, dosage 31.6 J/cm(2)) directly to their MCL during surgery. Group 2 (n = 4) received 9 doses of GaAlAs laser therapy applied transcutaneously on alternate days (wavelength 660 nm, average power 8.8 mW, pulse 10 kHz, dosage 3.5 J/cm(2)). The controls (Group 3, n = 4) received one session of placebo laser at the time of surgery, with the laser equipment shut down, while the sham injured Group 4 (n = 4) received no treatment. Biomechanical tests for structural stiffness, ultimate tensile strength (UTS), and load-relaxation were done at 3 weeks after injury. The stiffness and UTS data were normalized by expressing as a percentage of the left side of each animal before statistical analysis. RESULTS: The load-relaxation data did not show any differences between the groups (P = 0.18). The normalized stiffness levels of Groups 2 (81.08+/-11.28%) and 4 (92.66+/-13.19%) were significantly higher (P = 0.025) than that of the control Group 3 (58.99+/-15.91%). The normalized UTS of Groups 2 (81.38+/-5.68%) and 4 (90.18+/-8.82%) were also significantly higher (P = 0.012) than that of the control (64.49+/-9.26%). Although, Group 1 had higher mean stiffness and UTS values than the control, no statistically significant difference was found between these two groups. CONCLUSIONS: Multiple laser therapy improves the normalized strength and stiffness of repairing rat MCLs at 3 weeks after injury. The multiple treatments seem to be superior to a single treatment when the cumulative dosages are comparable between the two modes of application.

Effects of a therapeutic laser on the ultrastructural morphology of repairing medial collateral ligament in a rat model.

BACKGROUND AND OBJECTIVES: Low energy laser therapy has been shown to enhance mechanical strength of healing medial collateral ligament (MCL) in rats. The present study investigated its effects on the ultrastructural morphology and collagen fibril profile of healing MCL in rats. STUDY DESIGN/MATERIALS AND METHODS: Thirty-two mature male Sprague-Dawley (SD) rats were used. Twenty-four underwent surgical transection to their right MCLs and eight received only skin wound. Immediately after surgery, eight of the MCL transected rats were treated with a single dose of laser therapy at 63.2 J cm(-2), eight were treated with a single dose of laser therapy at 31.6 J cm(-2), the rest had no treatment and served as control. At 3 and 6 weeks after surgery, the MCLs were harvested and examined with electron microscopy for collagen fibril size, distribution, and alignment. RESULTS: Significant differences (P < 0.001) were found in fibril diameters from the same anatomical site and time period among different groups. The mass-averaged diameters of the laser-treated (64.99-186.29 nm) and sham (64.74-204.34 nm) groups were larger than the control group (58.66-85.89 nm). The collagen fibrils occupied 42.55-59.78, 42.63-53.94, and 36.92-71.64% of the total cross-sectional areas in the laser-treated, control and sham groups, respectively. Mode obliquity was 0.53-0.84 among the three groups. CONCLUSIONS: Single application of low energy laser therapy increases the collagen fibril size of healing MCLs in rats.

Therapeutic low energy laser improves the mechanical strength of repairing medial collateral ligament.

BACKGROUND AND OBJECTIVES: Low energy laser therapy has been shown to enhance collagen production but its effect on tissue strength is not well reported. We tested the effects of therapeutic laser on the strength of healing medial collateral ligaments (MCLs) in rats. STUDY DESIGN/MATERIALS AND METHODS: Twenty-four rats received surgical transection to their right MCL and eight received sham operation. After surgery, 16 received a single dose of gallium aluminum arsenide laser to their transected MCL for 7.5 minutes (n = 8) or 15 minutes (n = 8) and eight served as control with placebo laser, while the sham group didn't receive any treatment. The MCLs were biomechanically tested at either 3 or 6 weeks post-operation. RESULTS: The normalized ultimate tensile strength (UTS) and stiffness of laser and sham groups were larger than control (P < 0.001). The UTS of laser and sham groups were comparable. Laser and sham groups had improved in stiffness from 3 to 6 weeks (P < 0.001). CONCLUSIONS: A single dose of low energy laser therapy improves the UTS and stiffness of repairing MCL at 3 and 6 weeks after injury.