Introduction

Laminitis (Founder) is a common and severe disease in the horses (1). It's a complicated and interrelated sequence of inflammatory events and severely debilitating disease caused by inflammatory and pathologic changes of the laminar conjunction which offer the connection between the external hoof layer and 3^rd phalanx (2). Several structures along with dermo-epidermal junction, basement membrane, connective tissue of the laminar dermis, and the 3^rd phalanx are affiliated with the laminar architecture (3). When the laminar conjunction is disrupted and injured, the hoof-distal phalanx bond fails and laminitis arises (4). Impaired attachment between the external hoof layer and 3^rd phalanx cannot hold off the horse weight and ground reaction forces, leading to shearing and damaging the laminae and associated vasculature, drowning and/or circumvolution of the 3^rd phalanx; crushing the corium of the sole and coronet; and resulting in excruciating ache and lameness (5). The advancement of pathological changes can include fractious pain and foot deformation, may be career-ending, and ultimately result in the horse's demise. Various mechanisms including metabolic, mechanical and nutritional theories were introduced in spite of the laminitis etiology and pathogenesis have not been completely enlightening. (6). Thus, the treatment options are multifarious and directed at different components of the known pathophysiologic processes for achieving desired outcomes (7). While allopathic medicine has not been very successful in treating laminitis, there is circumstantial evidence that acupuncture reduces animal's lameness and suffering; however, evidenced-based scientific investigations are rare (8). Acupuncture has been widely applied as a complementary handling choice in human and veterinary medicine to produce analgesic effects, normalize physiologic functions, and treat clinical disorders (9).

Recently Kim et al. (10), showed that acupuncture therapy has been generally used in the veterinary medicine as a complementary treatment to chronic pain, inflammation and systemic disorders like equine laminitis. Acupuncture may be characterized as the stimulant of a definitive point on the body, known as an acupuncture point, or acupoint, with a specific method, resulting in a therapeutic effect (11).

The source of this treatment can be tracked to China as beginning as 2,200 to 3,000 BC. Historically, veterinary practitioners have used conventional acupuncture, bleeding needles, heat, cauterization and massage to provoke acupoints (12). Modern technology can also be used to excite acupoints, for instance electricity, laser, microwaves and injectable agents (13). Electro-acupuncture (EA) is a technique in which an electric current is passed to the animal through inserting a needle in an acupoint (14). The EA is generally considered to have stronger effects than other types of acupuncture methods and it has been adduced to be active for the laminitis treatment (15). It was hypothesized that acupuncture would reduce lameness severity in laminitic horses, for that many studies have lately concentrated on the impact of electroacupuncture in treating various aspects of equine illnesses like musculoskeletal, gastrointestinal, respiratory, and disorders of the reproductive system (16). Nevertheless, there is a lack of evidence-based research supporting the comparison between conventional acupuncture (CA) and EA in treating laminitis. So this investigation was intended to compare the efficiency of CA and EA in the laminitis treatment in racing horses.

Materials and methods

Animals

Twenty adult race horses aged between 18-22 years with laminitis from one geographical area were selected and initial degree of lameness, and lameness duration were recorded from 1/7/2019 to 1/10/2019.

Lameness evaluation

An objective evaluation of lameness was conducted using a wireless, body-mounted inertial gyroscope and accelerometer system called the “Lameness Locator” (Equinosis LLC, St. Louis, Missouri, USA). Three small wireless sensors were mounted on the horse's body. One axial accelerometer was mounted on the head and one on the pelvis, while a single-axial gyroscope was placed on the dorsal aspect of the right front pastern (17). The wireless data from the vertical expedition of the head and pelvis and angular speed of the right forelimb were collected using a laptop computer, analyzed, and reported as 'Vector Sum' (18,19). Additionally, Davidson (20) reported that lameness severity was evaluated at the same day by: a routine visual lameness examination following “American Association of Equine Practitioners” (AAEP) recommended 0 to 5 grading system as shown in table 1. Stride length measurements and force plate measurements. Lameness examination was performed before the 1^st week and nextthe CA and EA treatment. To ensure consistency and accuracy, the lameness evaluation was replicated three times for each horse and the arithmetic mean was calculated and used for statistical analyses.

The lengths of stride were measured when the animal walking above the sand-pit. The distance between the front edges of the imprint of each front leg was measured between successive strides. Five measurements were made to obtain (mean ± SD). Horses were led at a walk over the force plate which was mounted in a concrete walkway and concealed under the carpet. Responses for the four legs were recorded with an FM magnetic tape recorder (Model 3964A, Hewlett Packard, Palo Alto, California) for later analysis by a digital computer (Model PDP-12, Digital Equipment Corp, Maynard, Massachusetts) programmed to measure the maximal amplitude of the responses. The first five acceptable waveforms were utilized to obtain the (mean ± SD) for the maximal amplitude. The weight distribution percentage (%) between the four legs was calculated from the maximal amplitude values by mean for one leg/ summed mean for all legs × 100. The normal weight distribution is 30% and 20% for the front and hind legs, respectively; with this equation (21). The ultimate value at which every limb differed from these normal values was calculated and the four values were summed. This value was the "force plate index." Evaluation of all limbs was considered necessary since the lameness shifted in some horses.

Table 1: Clinical grading system of foreleg lameness (22)

Acupuncture treatments

Acupuncture therapy consisted of electric stimulation at acupuncture tips upon the front limbs that have been suggested for the therapy of laminitis (15). An examination of a diagnostic acupuncture palpation was performed on all horses and appropriate acupuncture points were chosen before each treatment. Starting from the 1^st week of study, electroacupuncture was applied for 20 minutes. Each horse in every treatment groups performed day-after-day for six consecutive weeks.

Lee and Faramarzi (23) clearly explained conventional acupuncture methods which included: dry needling, hemo-acupuncture, and aqua-acupuncture contingent on the problem nature and the treated acupuncture points area. For consistency, hemo-acupuncture (Small Intestine-1, Triple Heater-1, Large Intestine-1, QIAN-TI-TOU, and QIAN-TI-TOU mirror points) and dry needling (Heart-9, Pericardium-9, Lung-11, and QIANTI-MEN points) as shown in figure-1.

The points used for laminitis resembling points 100 - 117 at the forelimb and 140 - 149 at the hind limbs as shown in figure 2. These points are located caudal to the shoulder joint, caudal to the proximal metacarpal bone on the lateral aspect overlying the lateral palmar nerve, ventral and dorsal to the medial and lateral sesamoid bones, and on the foot. The probe of an acupuncture point finder (Hibiki-7 Acupuncture Point Finder, Asahi Corp., Japan) was moved over the skin until the point of decreased electric resistance was found (24).

The points were marked with indelible ink and all parameters were measured weekly.

Figure 1: Acupoints of the forelimbs (a,b) (24).

Statistical analysis

The statistical analyses were performed by Statically Analysis Software (SAS) application for Windows version 10. Descriptive analyses are presented as (means ± SD) for continuing variants. Data were not normally disseminated; thus, the non-parametric analysis was imperative. Lameness severity was analyzed via Wilcoxon signed-rank test. All statistical tests were one-sided and P

Figure 2: Acupoints of hind limbs (From the caudal view) (24).

Results

Assessment ofthe lameness levels after the CA and EA treatments were demonstrated in figures 3 and 4 both visual (following AAEP lameness grading) and objective (Lameness Locator) lameness examinations showed gradual statistical significant reduction (P<0.05) in the lameness severity and improvement in the gait of horses started at 4^th week after treatment and the decreasing continued significantly in 5^th and 6^th weeks. However, visual lameness examinations in figure 3 indicated a significant decrease (P<0.05) in AAEP grading in EA group 2.2 at 5^th week and decreased to 1.3 at the 6^th week, and simultaneously, remarkable significant difference (P<0.05) had been noticed in comparing with the averages of CA group at 5^th and 6^th weeks. In figure 4 objective lameness examination means, showed significant reduction (P<0.05) in lameness severity at fifth and sixth weeks at EA group when compared with the criteria at CA treated horses which reduced to 22.4 and 16.7, respectively. It also revealed significant decreasing (P<0.05) at last two weeks of this study in relative to other weeks. The stride lengths and force plate index averages revealed significant gradual improvement (P<0.05) in CA and EA in the left and right forelimb especially at the last three weeks (Figure 5 and 6).

Figure 3: Comparison of the lameness level difference between(CA) and (EA) treatment by visual (AAEP grading)lameness evaluation (mean ± SD). P-values

Figure 4: Comparison of the lameness level difference between CA and EA treatment by objective (lameness locator) lameness evaluation (mean ± SD). P-values

Figure 5: Stride lengths (mean ± SD) for conventional acupuncture (CA) and electroacupuncture (EA) for left and right forelimb treated horses.

Figure 6: Force plate indices (mean ± SD) for conventional acupuncture (CA) and electroacupuncture (EA) forelimb treated horses. P-values

Discussion

Veterinary literatures suggested that musculoskeletal diseases are responsive to acupuncture (25). Prescribed acupuncture points for treating laminitis have been portrayed (26). The laminitis treatment is multifaceted because of the complication of the laminitis and its pain. The objective of the treatment is to manage the pain and prevent a recurrence. Our study compared the response of lameness of racing horses to electroacupuncture treatment with conventional acupuncture; the outcomes uncovered that applying to EA treatment further decreased the lameness rigor in racing horses with laminitis.

We found that the lameness horses significantly improved after the (EA) treatment more idealistic and convened in comparing with CA. The management of lameness through controlling the pain in laminitic horses is a key element for determining prognosis and rehabilitation. Available treatments for laminitis are very limited, especially EA, mainly because of limited existing knowledge of the etiology and pathophysiology of the disease (27). Although several treatment options have been suggested to manage laminitis, they are influenced by the time and effort needed for application and by side effects (28). In a previous study reported by Parsons et al. (29) that 19% of laminitic horses referred to veterinary teaching hospitals suffered from permanent lameness, while 48% were eventually euthanized.

The neurophysiological mechanisms of acupuncture analgesia have been recorded and included: opiate and non-opiate pain modulation, hippocampal nitric oxide synthase activity, and the expression of various mediators of neurologic inflammation have been documented as well. (10).

Acupuncture provides a drug-free and safe alternative treatment with minimum side effects and rare adverse reactions (30). Acupuncture influences multiple systems which are usually involved in the laminitis development, such as musculoskeletal, gastrointestinal and immune systems (31). It has been recommended that acupuncture prevents and modifies the perception of pain at many various degrees of the nervous system including a raise in opioid peptides secretion, oxytocin concentration and serotonin receptors activation (32,33). In the present study, we used hemo-acupuncture as part of our treatment formula for all horses. Hemo-acupuncture causes bleeding at acupoints and is related to the phlebotomy effect, which might relieve extravasated blood stagnation and therefore improve local circulation (34).

Laminitis is linked to hypoperfusion, ischemia and necrosis of lamellae (35). It has been stated that destruction of the lamellar basement membrane is associated with activation and deactivation of metalloproteinases (MMPs), including MMP-9 and MMP-2 as well ADAMs (a disintegrin and metalloproteinases), originally also known as MDC proteins (metalloproteinase /disinterring/ cysteine -rich) with thrombospondin motifs-4 (ADAMTS-4); which are well significant in the laminitis development (36).

Moreover, earlier studies described that acupuncture inhibits expression and activation of metalloproteinases (MMPs) 2 and 9 that are associated with chronic laminitis (37). Hence, acupuncture may not only improve the immediate clinical signs, but may also prevent the progression and recurrence (e.g., the occurrence of acute episodes) of laminitis (38); yet, more research is warranted. The complex nature of laminitis and the acupuncture likelihood influence on several body systems suggest acupuncture as an appropriate ancillary treatment (39). Furthermore, acupuncture therapy does not interfere with other treatments such as therapeutic shoeing, medications, dietary restrictions; thus, it can be offered in parallel with other acute and chronic laminitis therapies (40). Acupuncture increases the synthesis of nitric oxide (NO) activity around acupoints (41).

The nitric oxide is a regulator key of local circulation and may improve local circulation of L-arginine and glyceryl trinitrate (42). Local impacts of acupuncture, including pain relief, alteration in local circulation, and mediation of inflammation, are associated with the increase of calcitonin peptide and synthesis of nitric oxide activity (NO) (43). Therefore, it is probable that acupuncture treatment improves lameness through pain modulation and local circulation, as well as preventing the exacerbation and relapse of laminitis (44).

Acupoints are central areas of decreased electrical resistance that are shared to specific anatomic locations; those points are associated with high concentrations of autonomic innervation, vacuolization, and lymphatic drainage/vessels within the fascia and muscles (45). Most of the acupoints that were used in the current study, involving HT-9, SI-1, TH-1, LI- 1, LU-11, PC-9, and QIAN-TI-MEN, have been prescribed by past studies (21). It has been suggested to use of QIAN-TI-TOU and its mirror points in the hoof pain therapy (46). The addition of QIAN-TI-TOU and its mirror points were deemed beneficial as local toe points to remedy the pain in laminitic patients.

Conclusion

From our results we concluded that there was a significant improvement in the movement of the horses with laminitis after continuedelectroacupuncture treatment when compared with conventional acupuncture treatment.

Acknowledgments

We would like to acknowledge all veterinary staff and nurses for their assistance and facility during animal handling.

Conflict of interest

The authors declared that there is no conflict of interest.