To study the difference of the values of Young's modulus between the middle part and the inferior extremity of rabbit renal cortex.

Ten Japanese white rabbits were used for this study. The right renal vein was ligated. At time intervals of 15, 30, 60 and 90 minutes after ligation, the values of Young's modulus from different parts of the right renal cortex were recorded. Independent sample t test was used to compare the difference of the values of Young's modulus from the middle part and the inferior extremity of renal cortex at the same time point. Single factor variance analysis was used to compare the values of Young's modulus at the same point at difference time.

Before renal vein ligation, the values of Young's modulus from the middle part and the inferior extremity of renal cortex were (15.93±1.70) kPa and (4.66±1.4) kPa. After the ligation, the values from those two parts of the kidney were as follows: 15 min after ligation, (34.84±4.91) kPa and (10.95±3.09) kPa; 30 min after ligation, (41.55±3.19) kPa and (20.39±4.06) kPa; 60 min after ligation, (50.63±2.73) kPa and (30.96±4.98) kPa; 90 min after ligation, (56.61±2.96) kPa and (42.40±5.79) kPa. The value of Young's modulus from the middle part of renal cortex was significantly higher than the inferior extremity of renal cortex, and the difference was statistically significant (t=21.63, 7.44, 7.19, 5.26 and 2.41, all P<0.05). The values of Young's modulus from different parts of the renal cortex after renal vein ligation were significantly higher than those before the ligation (t=-3.30, 3.38, -2.47, 1.83, all P<0.05), and the values increased gradually with time increased after ligation (t=-5.31, 8.26, -7.81, 3.65, all P<0.05).

The values of Young's modulus from the middle part of renal cortex were higher than those of the inferior extremity of renal cortex determined by shear wave ultrasound elastic imaging technique. It is suggested that there is anisotropy in the renal cortex of rabbit. Prior to and within 90 min following renal vein ligation, the values of Young's modulus from the middle part of renal cortex were higher than those of the inferior extremity of renal cortex determined by shear wave ultrasound elastic imaging technique.