Basic study of the hepatic impairment induced by the total parenteral nutrition: The stereological analysis on the structure of the bile canaliculi and microvilli

Total parenteral nutrition has been used in surgical field. One of the side effects is hepatic impairment. In the present study, we use electron microscopy and stereology to evaluate the effects of different composition of TPN on the morphological changes of hepatic organelles, try to improve the knowledge of total parenteral nutrition associated cholestasis (TPN-AC). Twenty-five adult rats were divided randomly into four groups. Gr.I (N=6) was sham operated and fed with regular rat chow. Gr.II (N=6) Gr.III (N=7) and Gr.IV (N=6) were treated with intravenous infusion of TPN with different compositions. Gr.II 20% glucose and 3.5% Molipron F®, Gr.III 20% glucose and 3.5% Aminic®, Gr.IV 30% glucose and 3.5% Aminic®. The main difference between Molipron F® and Aminic® is the concentration of Branched Chain Amino Acid (BCAA); which is 22.6% (Molipron F®) versus 35.9% (Aminic®). After seven days of TPN treatment, the rats were sacrificed, liver tissue harvested for electron microscopic examination and stereology morphometric study. Microvilli become edematous, distorted and decreased in numbers in all TPN groups, most severe in Gr.II. Using the stereology technique, the relative length, surface, volume of bile canaliculi and microvilli were calculated. The surface density of bile canaliculi wall in Gr.III is 40% less than the control group, the volume density of bile canaliculi space remained unchanged in all four groups. The microvilli changed its surface density in Gr.III, which is significantly increased than the control group. From the above data, we concluded that bile canaliculi become expanded and rounded in Gr.III, the microvilli became elliptical and flattened, which is more efficient in driving the bile. With wider bile canaliculi pathways and more efficient mocrovilli in Gr.III, total parenteral nutrition associated cholestasis is less prominent in Gr.III. Branched chain amino acid enriched solution is a better solution in TPN. Stereology offer morphometric data is helpful in TPN-AC study.