Alterations in Neurons of the Brainstem Due to Administration of Inhaled Tetrahydrocanabinol: A Quantitative Histopathology Study on Rats

Abstract

A Quantitative Histopathology study on rats’ brainstem was used to analyze morphological alterations in the neurons and glial cells of rats that received inhaled tetrahydrocanabinol for 4, 8 and 12 weeks. Puffing of smoke was performed with the use of a Hamilton syringe delivering 100ml puffs at 20s intervals into the nose only manifold. Smoke was first pumped into a 500ml dilution chamber with the aid of a vacuum pump. The smoke was then displaced from the dilution chamber through the nose-only manifold at 300ml/min; the rats received inhaled THC at 5ml/sec for 5 minutes. After administration for varying durations a selective cell staining of the neurons and glial cells in the rat’s pons, medulla and midbrain was carried out and used to study visible morphological changes in the tissues. Sections from the pons, medulla and midbrain were stained on slides for viewing under the microscope and photographed. Quantitative and qualitative histopathology study of photomicrographs was then used to analyze changes in the morphology and number of neurons. There was an increase in the ratio of neuronal cells comparing between the control and the treated groups with the pons (1:8), medulla (1:3) and the midbrain (1:5) which suggests neurogenesis and on further analysis of the slides show evidence of cell division. These findings can be of great importance in the study of neurodegenerative diseases and in understanding the influence of THC on brain.