A Time-Limited and Partially Reversible Model of Hypoganglionosis Induced by Benzalkonium Chloride Treatment.

Abstract

Serosal application of benzalkonium chloride (BAC) has been previously applied to produce a model of aganglionosis; however, confusion remains regarding the extent of chemical ablation of enteric myenteric plexus after BAC treatment. The time sequence of BAC-induced effects on the myenteric plexus of the rat colon was determined and followed the morphologic changes. After sacrifice of animals 7, 14, 28, 56, 84 or 168days postintervention, colonic tissue samples were removed, fixed in formalin, and cut into 5-μm longitudinal sections for histological analysis. The neural analysis was used to re-evaluate BAC treatments for the appropriate model. Compared with rats in sham groups, rats in 0.1%-30-min BAC group maintained only 15.27±4.80% of ganglia per section in a 1-cm/5-μm slice and 11.76±2.30% of ganglionic cells after 28days, the lower and stable number of ganglionic cells between Day 7 and 84 (from 11.67±2.10 to 19.05±5.10%). Although an increase, ganglionic cell numbers did not recover at Day168 when compared with the numbers in sham groups. The results showed that characteristics of rats in the 0.1%-30-min BAC group between Day 7 and 84 most closely kept in stable state, suggesting that these treatment parameters are ideal for producing a hypoganglia model of hypoganglionosis.