NORA Manufacturing Sector Strategic Goals
927002Q - Animal Models of Hand-Arm Vibration SyndromeStart Date: 10/1/2004
End Date: 9/30/2009
Principal Investigator (PI)Name: Kristine Krajnak
Funded By: NIOSH
Primary Goal Addressed3.0
Secondary Goal AddressedNone
Attributed to Manufacturing75%
The goals of these studies are to use animal models to establish dose response relationships between vibration and soft tissue injuries, and understand the cellular mechanisms underlying the development of these injuries. Employees in the manufacturing, mining and construction sectors are often exposed to upper limb vibration through the use of powered hand tools. This type of vibration exposure can result in damage to soft tissues of the hands and arms. By understanding the cellular responses of soft tissues to vibration exposure, we can determine what types of vibration exposures are most damaging so that more effective prevention and treatment strategies can be developed. In addition, dose-response data can be used to improve existing guidelines limiting vibration exposure and guidelines describing methods for diagnosing vibration-induced injuries. These studies will contribute to the following sector and cross-sector strategic goals: Construction Sector Goal 7, Manufacturing Goal 3, and the musculoskeletal cross-sector goals 2 and 3. All these goals focus on reducing the number and severity of musculoskeletal disorders in the workplace.
It is hypothesized that prolonged exposure to vibration will cause peripheral and systemic changes in both vascular and nervous systems and that these changes are dependent in part on multiple exposure, environmental, and individual risk factors. Several different animal models will be developed to study the pathophysiological mechanisms associated with prolonged exposure to vibration. In some models, the tails, or paws of restrained rats are exposed to vibration under conditions in which the duration and magnitude of vibration are highly controlled. In another model, unrestrained rats are trained with operant conditioning techniques to voluntarily and repetitively pull on a vibrating bar to achieve prolonged vibration exposures. Each model has unique advantages that will allow for the study of different mechanisms associated with vibration-related occupational disorders. In all cases, the underlying cellular and molecular mechanisms of vibration-related disorders will be studied. Functional deficits concomitant with the prolonged vibration exposures also will be assessed with techniques commonly used with human subjects, such as temporary tactile and thermal perception shifts, peripheral blood flow, and neurometry, grip strength and manual dexterity. The principal investigators comprise a multidisciplinary team that is uniquely situated in a state-of-the-art research facility with access to advanced biological and engineering support. This project also will involve multiple internal and external collaborations with experts in the fields of hand-transmitted vibration, vascular biology, and neurophysiology.
• Characterize the cellular and molecular changes that occur in peripheral vasculature and nerves in response to prolonged vibration exposures.
The Bureau of Labor Statistics (2004) reports that approximately 1.5 million workers use powered and pneumatic hand tools on the job. The majority of workers using these tools are employed in the manufacturing, mining and construction sectors. Workers using powered hand tools are exposed to high levels of upper limb vibration. Depending on occupation and other exposure factors, approximately 50% of these workers will develop Hand-Arm Vibration Syndrome (HAVS). HAVS is characterized by vasospasms in the fingers and hands, loss of tactile and thermal sensation in the digits, reductions in grip strength and reductions in manual dexterity. There is evidence that factors such as duration of exposure, acceleration rate of the vibration, and cold working environments serve as risk factors for developing HAVS. However, comprehensive surveillance and basic scientific studies in this area have been limited, precise exposure limits have not been determined, and the role that these factors play in the development of vascular, nervous system and muscle and joint damage has not been established. HAVS has significant long-term effects on vascular, sensory and motor function, and is a work-related musculoskeletal disorder and thus a NORA cross-sector-related research priority. The goal of these studies is to use animal models to determine the risk associated with factors linked to the development of HAVS (e.g., vibration frequency, amplitude, duration, and applied force) and to understand the underlying cellular mechanisms responsible for causing this disorder. These studies will provide data that can be used to improve exposure guidelines for the workplace and identify effective monitoring and prevention strategies, along with treatment interventions for HAVS.