Evaluating the Histopathological Effects of Short-term and Long-term Doses of Ketamine Injection on Heart Tissue of Male and Female Rats

Introduction: Ketamine is a general anesthetic drug that acts by inhibiting the NMDA receptoran important component of excitatory neurotransmission. Existing of NMDA receptors all over the central nervous system and the special type of anesthesia induced by ketamine, called dissociative anesthesia  has led to its use as an analgesic and also paved the way for abuse. Ketamine affects the cardiovascular system by increasing indices such as heart rate, blood pressure, and cardiac output. Methods: For further evaluation of ketamine effects on heart tissue, we used 15 male and 15 female Wistar rats and divided them into 6 groups, including male and female control groups (MC and FC), male and female short-term exposure (MS and FS), and male and female long-term exposure (ML and FL) to ketamine. Each group included 5 Wistar rats. The ML and FL groups received 75mg of ketamine once a week for 4 weeks in the posterior muscle of the thigh and the MS and FS groups received 25mg of ketamine 3 times a week for 4 weeks at the same site. Results: After preparation of histopathological slides, it was observed that only in the group of female mice receiving long-term ketamine, empty spaces and intercellular distances increased, and in the group of male mice receiving long-term ketamine, in addition to the increase of intercellular spaces, tissue accumulations were also observed in the heart tissue. Conclusion: This study showed that long-term ketamine injection in both sexes can cause some qualitative changes in heart tissue. Expanding the duration of long-term exposure to ketamine and more studies based on sexes can lead to more findings.