The Possible Protective Role of Resveratrol against Zinc Oxide Nanoparticles Induced Hepatic Tissue Injury in Adult Albino Rat

Abstract Background Zinc oxide nanoparticles (ZnO NPs) are widely used in industries and medications. This may elevate the probability of their existence in the environment, which may have harmful side effects on different body organs, especially on the liver. So it became mandatory to search for natural hepatoprotective elements such as Resveratrol. Aim of the Work The aim of the present work was to determine the effect of zinc oxide nanoparticles on the histological structure and biochemical markers of the liver of adult male albino rats and to evaluate the possible protective role of Resveratrol. Material and Methods 40 adult male albino rats aged 3-6 months, were divided randomly into four groups; Group I (Control group), which consisted of 10 male albino rats with free access to food (rat chew) and water; Group II (ZnO NPs group), which included 10 male albino rats, which received a dose of 50 mg/kg body weight ZnO NPs through oral gavage daily for 4 weeks; Group III (Resveratrol group) was composed of 10 male albino rats which received a dose of 20 mg/kg body weight Resveratrol through oral gavage daily for 4 weeks, and Group IV (ZnO NPs + Resveratrol group) included 10 male albino rats which were co-administered with a combination of ZnO NPs at a dose of 50mg/kg body weight and Resveratrol at a dose of 20 mg/kg body weight dose through oral gavage daily for 4 weeks. At the end of the experiment, blood samples were collected for serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP). All the animals were sacrificed, and the liver was extracted and processed into paraffin blocks for light microscopic examination. A morphometric study and a statistical analysis were done. Results The present work demonstrated that liver sections obtained from adult male albino rats that received ZnO NPs showed disorganized hepatic architecture, severe affection of the hepatocytes, which had small darkly stained nuclei, and deep acidophilic cytoplasm. The hepatocytes sometimes showed extensive cytoplasmic vacuolations. Most hepatocytes had small apoptotic nuclei and were surrounded by clear halos. While some hepatocytes lost their cell boundaries and coalesced together. Central veins were dilated, distorted, and congested with areas of epithelial lining detachment. Most of the blood sinusoids appeared congested with marked inflammatory cell infiltration. The portal tracts showed vascular congestion, dilatation, and proliferation of the bile ducts. There was a marked increase in the collagen deposition around the portal tracts, central veins, and in-between hepatocytes. Marked depletion of glycogen content with sporadic positive PAS reactions within the cytoplasm of the hepatocytes was also noticed. Hepatocyte apoptosis was evident by a significant increase in caspase-3 expression compared to the control group. On the other hand, ZnO NP +Resveratrol group showed the restoration of normal hepatic lobules with few areas of subcapsular haemorrhage. Most hepatocytes appeared polygonal in shape, with acidophilic cytoplasm and central rounded vesicular nuclei. While few hepatocytes appeared degenerated with dark stained pyknotic nuclei and cytoplasm showed hydropic degeneration. Most of the blood sinusoids returned to their normal sizes with flattened endothelial cells. However, sometimes they were congested, dilated, and contained Kupffer cells. Some central veins appeared congested. The portal tract also returned to its normal size with a marked decrease in inflammatory cell infiltration and showed apparent minimal collagen fiber deposition. Another finding in the present work was that Resveratrol restored the glycogen content of the hepatocytes which were depleted in ZnO NPs group. This was marked by a strong PAS positive reaction in the cytoplasm of most hepatocytes, with few hepatocytes with weak PAS reaction. Resveratrol co-treatment with ZnO NPs significantly reduced the degeneration and necrosis of hepatocytes. This was evident in our study by the apparent negative Caspase-3 reaction in the cytoplasm of most hepatocytes. Clear deterioration of liver function tests was observed in ZnO NPs group compared with the control, with marked improvement in the group treated with ZnO NPs and Resveratrol together. Conclusion The present study demonstrated the degenerative and hepatotoxic effects of ZnO NPs on the histological structure and function of the liver and the hepatoprotective role of Resveratrol against these effects.