Ind Health

To formulate more accurate guidelines for musculoskeletal disorders (MSD) linked to Hand-Arm Vibration Syndrome (HAVS), delineation of the response of bone tissue under different frequencies and duration of vibration needs elucidation. Rat-tails were vibrated at 125\ue2\u20ac\u2026Hz (9 rats) and 250\ue2\u20ac\u2026Hz (9 rats), at 49 m/s(2), for 1D (6 rats), 5D (6 rats) and 20D (6 rats); D=days (4\ue2\u20ac\u2026h/d). Rats in the control group (6 rats for the vibration groups; 2 each for 1D, 5D, and 20D) were left in their cages, without being subjected to any vibration. Structural and biochemical damages were quantified using empty lacunae count and nitrotyrosine signal-intensity, respectively. One-way repeated-measure mixed-model ANOVA at p<0.05 level of significance was used for analysis. In the cortical bone, structural damage quantified through empty lacunae count was significant (p<0.05) at 250\ue2\u20ac\u2026Hz (10.82 \uc2\ub1 0.66) in comparison to the control group (7.41 \uc2\ub1 0.76). The biochemical damage was significant (p<0.05) at both the 125\ue2\u20ac\u2026Hz and 250\ue2\u20ac\u2026Hz vibration frequencies. The structural damage was significant (p<0.05) at 5D for cortical bone while the trabecular bone showed significant (p<0.05) damage at 20D time point. Further, the biochemical damage increased with increase in the duration of vibration with a significant (p