Manganese-enhanced magnetic resonance imaging for studying olfactory dysfunction in rats / 中华耳鼻咽喉头颈外科杂志

ABSTRACT

<p><b>OBJECTIVE</b>To study the olfactory function in rats by manganese-enhanced magnetic resonance imaging (MEMRI) and explore the regeneration of olfactory system from the imaging.</p><p><b>METHODS</b>Thirty-five adult male Sprague-Dawley (SD) rats were randomly divided into three groups. Twenty rats with bilateral nasal instillation of TritonX-100 were used as olfactory dysfunction model group (M group). The rats in this group received menthocamphorate stimulation. Ten rats with bilateral nasal instillation of sterile saline were used as olfactory normal group (N group), and were randomly divided into two groupsone group received menthocamphorate stimulation (N1 group), another group received odorless air (N2 group). The remaining five rats were used as the blank control (control group). All images were acquired with a 7.0 T micro-MR scanner. Signal-to-noise ratios (SNR) in the olfactory bulb (OB) were measured by Image J.</p><p><b>RESULTS</b>MEMRI could clearly show the normal olfactory pathway in rats. MEMRI displayed a reversible change during the stages of olfactory recovery after injury. For the olfactory dysfunction model group (M group), the total volume of rat olfactory bulb at the initial, the 10th day, the 20th day, the 30th day and the 60th day were (49.44 ± 0.81), (32.85 ± 0.79), (27.78 ± 1.07), (35.89 ± 1.04), (43.63 ± 1.13) mm(3) respectively. At the 20th day after olfactory injury, the SNR in the OB was the lowest for 9.78 ± 0.07, when at the 60th day, the SNR recovered to 30.68 ± 1.01, which increased to near normal (N1group, 33.08 ± 0.15; N2 group, 31.31 ± 1.12), the SNR had no significant difference among the three groups (F = 3.04, P > 0.05).</p><p><b>CONCLUSION</b>The MEMRI is an objective method to detect the olfactory function, and the olfactory system has the regenerative property after injury.</p>