It has been known since ancient times that lead is virtually toxic to every organ of body including central nervous system where it may manifest as encephalopathy and hyposmia yet the exact mechanism of these clinical manifestations remains inconclusive. The present study was aimed to see the microscopic changes in the olfactory bulb of mice induced by oral administration of a lead compound in adult albino mice. A total number of 36 adult albino mice of either sex were included in the present study consisting of equal numbers in both control and experimental groups. Experimental group received 4.5% and 5% lead nitrate and lead acetate trihydrate orally and with dietary supplement for a period of 3 weeks then animals of all groups were euthanized with overdose of general anaesthesia and perfused with 10% formalin. Olfactory bulbs were dissected out and processed for paraffin embedding. Sections of 10μ thick were stained with H&E and observed under light microscope. On gross examination brains from the experimental group revealed generalized edema and petechial haemorrhages. Histopathology of the olfactory bulbs revealed edema and congestion with vacuoles of variable sizes almost throughout. Distortion of glomeruli, clumping of periglomerular cells and increasing number of pyknotic cells were also noticed. It was concluded that lead has toxic effects on the central nervous system including olfactory bulb in the form of edema, microscopic hemorrhages and neuronal loss which may explain the clinical manifestations of lead toxicity.
