Modulation of heat shock protein immunolocalization in cerebral cortex by melatonin therapy in heat stressed rats
Journal of Histology and Histopathology
Heat stress leads clinically to manifestations of central nervous system dysfunction. Heat shock proteins (HSPs) function as molecular chaperones protecting the cells from damage. Melatonin has therapeutic and prophylactic effects on heatstroke-induced multiple organ dysfunction. The present work aimed to investigate the protective effect of melatonin against heat stress-induced histological and HSP60 immunoexpression alterations of cerebral cortex in adult male albino rats. Forty adult male
... ino rats were used and divided into three groups; I (control) II (3 days heat stressed) and III (3 days heat stressed with melatonin treatment). Cerebral cortex specimens were processed to prepare sections for light microscope examination and blood samples were obtained for oxidative stress and antioxidant analysis. Hematoxylin and eosin stained sections showed degenerative changes in cerebral cortex of rats exposed to heat for 3 days in the form of apoptotic neurons and swelling of astrocytes processes. Neuropil edema, subarachnoid hemorrhage and congested blood vessels were also observed with accompanied increase in serum oxidative stress markers and decrease in antioxidant marker. Melatonin treatment with heat stress showed more preserved nervous tissue with accompanied increase in serum antioxidant marker. HSP60 immunoexpression was weak cytoplasmic in control group which significantly increased and became strong cytoplasmic after 3 days of heat exposure. With melatonin treatment with heat stress nuclear, HSP60 immunoexpression was moderate nuclear in some neurons and strong cyoplasmic in others. In conclusion, melatonin ameliorates heat exposure induced degenerative changes in cerebral cortex of adult male albino rats most probably through antioxidant effect with modulation in HSP60 immunoexpression pattern. Hence, more attention should be thrown to melatonin as a protective treatment to avoid heat stress degenerative effect on cerebral cortex. by a digital camera (Canon Power Shot A620, England, UK). 21. Wu WS, Chou MT, Chao CM, Chang CK, Lin MT and Chang CP. Melatonin reduces acute lung inflammation, edema, and hemorrhage in heatstroke rats. Acta Pharmacol Sin. 2012; 33:775-82. | Article | PubMed Abstract | PubMedFullText 22. Dudka J, Bojarska A and Reiter RJ. Protective effects of melatonin against thioacetamideinduced liver fibrosis in rats. J Physiol Pharmacol. 2015; 66:567-79. | Pdf | PubMed 24. Tian YF, Lin CH, Hsu SF and Lin MT. Melatonin improves outcomes of heatstroke in mice by reducing brain inflammation and oxidative damage and multiple organ dysfunction. Mediators Inflamm. 2013; 2013:349280. | Article | PubMed Abstract | PubMedFullText 25. Bancroft JD and Gamble M. Theory and Practice of Histological Techniques., 6 th ed. Churchill Livingstone, Scotland, London. 2008; 125-138. 26. Kiernan JA. Histological and Histochemical Methods: Theory and Practice. Third edition, Arnold publisher, London, New York and New Delhi. 2001; 111-162. 27. Placer ZA, Cushman LL and Johnson BC. Estimation of product of lipid peroxidation (malonyl dialdehyde) in biochemical systems. Anal Biochem. 1966; 16:359-64. | Article | PubMed 28. Deshpande GG, Heidemann SM and Sarnaik AP. Heat stress is associated with decreased lactic acidemia in rat sepsis. Crit Care. 2000; 4:45-9. | Article | PubMed Abstract | PubMedFullText 29. Tappel AL. Glutathione peroxidase and hydroperoxides. Methods Enzymol. 1978; 52:506-13. | PubMed 30. White MG, Luca LE, Nonner D, Saleh O, Hu B, Barrett EF and Barrett JN. Cellular mechanisms of neuronal damage from hyperthermia. Prog Brain Res. 2007; 162:347-71. | Article | PubMed 31. Muchowski PJ and Wacker JL. Modulation of neurodegeneration by molecular chaperones. Nat Rev Neurosci. 2005; 6:11-22. | Article | PubMed 32. Le NP and Brown JW. Characterization of the Thermoneutral Zone of the Laboratory Rat. FASEBJ. 2008; 22. | Article therapy against heat stress.