English abstract
Over 300 million people consume smokeless tobacco products (STPs) around the world with more than forty types. Afzal is one type of STPs which is used illegally in Oman and reported to contain hazardous chemicals such as nicotine, tobacco specific
nitrosamines and heavy metals. The aims of this study were to determine the lethal concentration (LC50) of Afzal on chick embryos, to study the effect of different concentrations of Afzal on the kidney of chick embryos using light microscopy (LM),
transmission electron microscopy (TEM) and scanning electron microscopy (SEM) including energy dispersive spectroscopy (EDS) and to elucidate possible histopathological effects on chick embryo kidney. Initially, lethal concentration (LC50) of Afzal STP on chick embryos was determined in which 11 concentrations were tested against embryos and found to be 3.3%. Based on LC50 results, 1%, 2% and 3% Afzal concentrations were selected to investigate its effect on kidney tissues. Egss were exposed then tissues were processed for light, transmission and scanning electron microscopy investigations. LC50 experiment findings showed that Afzal LC50 on chick embryos was 3.3% based on statistical probit analysis. Whereas, LM findings showed
intact architecture of renal corpuscles including Bowman's capsules, glomeruli and tubules compared in all tested groups. TEM findings were supportive which showed normal ultra-structural morphology of cortical tissues such as Bowman's capsules,
glomeruli and tubules. Foot processes, podocytes, mesangial cells, epithelial and endothelial cells were all intact. Moreover, there were no changes seen in the proximal convoluted tubules (PCTs) with their intact brush borders and distal convoluted tubules (DCTs). EDS findings did not show any presence of heavy metals on the PCTs. The present study indicated that all investigated groups of structural features revealed normal appearance of growing chick embryonic kidney tissues. Further studies on other embryonic organs such as liver and brain should be done for better understanding.
Keywords: smokeless tobacco product, Afzal, kidney, transmission electron microscopy, scanning electron microscopy, energy dispersive spectroscopy.
