Reversal of Hepatomegaly Following Cessation of Kratom Consumption in C57BL/6 Male and Female Mice

Kratom is derived from the leaves of a Southeast Asian plant, Mitragyna speciosa . Mitragynine is one of several compounds in kratom, but has been shown to bind to the opioid receptors. Numerous people in the United States take kratom to alleviate pain, help with depression, and as a substitute during opioid withdrawal. Little is known about the effects kratom has on various organ systems. The objective of the current study was to determine if hepatomegaly caused by 10 days of consuming kratom can be reversed after 30 days of discontinuance of kratom. A kratom tea was made by placing the kratom powder in a tea bag and boiling for 10 min in spring water that was brought to a pH 4 with fresh lemon juice. Mice received a liquid diet for 3 days of acclimation. Beginning on day 6, mice received the liquid diet (control) or the liquid diet made with kratom tea with various doses of mitragynine (0.175 mg/kg BW −1 ) as determined by HPLC. These doses were based on allometric scaling to approximate human doses. Mice were paired fed for 10 days and tissues collected day 11 from half the mice. The remaining mice were weaned back to their pellet diet and tissues were collected 4 weeks later. Blood was collected via heart puncture and serum stored at −20°C to be analyzed for liver enzyme function and mitragynine concentration. Kidneys and small intestines were collected for analyses in future studies. Livers were collected, wet weight recorded, and portions were snap frozen in liquid nitrogen for RNA analysis and embedded in OCT or fixed in 10% buffered formalin for histology. Consumption of daily large doses of kratom appeared to have no outward health issues when the daily activities of the mice were observed. Liver size was greater (P < 0.01) on day 11 in mice consuming kratom (4.42 ± 0.31% of body weight; n = 10) as compared to controls (6.52 ± 0.31% of body weight; n = 6). At 4 weeks following cessation of kratom, liver size was no different in kratom‐treated (4.88 ± 0.44% of body weight; n = 6) as compared to control mice (4.51 ± 0.27% of body weight; n = 10). Adhesions of the liver to the diaphragm, stomach, right kidney, or small intestine were observed at 4 weeks in mice that received kratom. Alterations to enzymes or inflammatory cytokines in liver tissue have not yet been evaluated. Consumption of kratom in as few as 10 days causes hepatomegaly that can be reversed if kratom is discontinued. The extent of liver damage and dysfunction and effects on future health status has yet to be determined. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .