Color quantification and comparison of multiple recovery methods in different bovine and porcine tissues

Abstract

Cadaver dissection is still considered an essential procedure for anatomy education. Since the description of Formaldehyde (FA), multiple solutions and reagents have been applied and developed to stop the natural decomposition process. All of them aiming to slow down/stop corpses decay and to ameliorate specimen's appearance, by avoiding enzyme activity and acting as fungicides and bactericides. Nevertheless, hard and soft fixated cadavers used in anatomy classes still lose live aspects of a human body regarding shape, smell and color.Tissues preserved with FA, as the most common reagent to fixate cadavers in spite of its known health drawbacks exhibit a dramatic color change, especially in muscle tissue due to the effects of chemical reactions with myoglobin. We compared color recovery in previously FA fixated specimens after six color recovery reagents were applied and a low FA solution was used as final preservation.Five groups were treated. Each group included four tissues: bovine skeletal muscle (SM) and liver, porcine cardiac muscle (CM) and kidney. All specimens were obtained under our IACUC endorsement 17‐021 and acquired as food industry products, in order to avoid human tissue loss until results were obtained.All specimens were fixated with 10% V/V FA before immersed in their respectively assigned solution. Color recovery proposed agents were: mineral textile stain, sodium bicarbonate, sodium bisulfite, Lauryl‐dimethyl‐benzyl‐ammonium bromide (LB) and oxidative KOH degradation. At a 45‐day mark, all groups except LB, were submerged in a low (2%) FA solution used at our laboratory. LB group was kept submerged in the same solution. After six months standardized pictures were taken for all specimens.To quantify color recovery, three color spaces were used: Red, Blue, Green (RGB), Hue, Saturation, Value (HSV) and Luminescence a and b (Lab). An algorithm was developed in Matlab® and histogram analysis was pursued, highlighting maximum red color distribution in each channel.RGB has three channels: red, blue and green color distribution. At HSV space, a color ring from 0 to 360° was used for Hue, a 0 to 1 scale was used for Saturation (white to pure color) and a 0 to 1 scale was used for Value (black to white). For Lab space, the mean of each channel was used to find the delta E, allowing to calculate color difference between images.Amongst the solutions the least amount of change in color was obtained with the mineral textile stain. At RGB space for SM, liver, CM and kidney showed the maximum red color at 256, 11, 256 and 255 respectively. Compared at six with values 146, 170, 188 and 218 respectively. In HSV, SM presented a Hue at first day of 354,40° and 4,23° at six months, and a Saturation of 0,56 and 0,55. Liver showed a Hue change from 9,88° to 14,11° and Saturation from 0,73 to 0,64. CM exhibited a color reduction from 352,94° to 14,12° for Hue and from 0,43 to 0,66 for Saturation. Kidney presented from 358,58° to 11,29° for Hue and 0,35 to 0,57 for Saturation. The delta E for SM was 7.26, liver 14.17, CM 30.74 and kidney 18.13. The best color space to compare with the human perception is HSV, which demonstrated the loss of color and the distribution in its HSV values.With the developed algorithm no solution preserved color significantly, reflected not only in the maximum and minimum reduction of each canal, but its distribution and displacement in the histogram.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.