Milica Veljković

Morphological and morphometric study of protective effect of green tea in gentamicin-induced nephrotoxicity in rats.

AIMS One of the most popular beverages worldwide, green tea, was investigated for its potential protective effect in a rat model of gentamicin-induced nephrotoxicity by monitoring functional and morphological changes in kidneys. MAIN METHODS The study was conducted on four groups of rats: control group (C), treated with only gentamicin (GM), treated with only green tea (GT) and treated with both gentamicin and green tea (GT+GM). Kidney function, oxidant and antioxidant parameters of renal tissue, as well as histopathological studies were assessed. Morphometric analysis was used to quantify these histopathological changes. KEY FINDINGS Gentamicin caused significant elevations in serum creatinine and urea and oxidative stress parameter (AOPP), while antioxidative enzyme catalase was significantly decreased. Histological sections of kidneys in GM group revealed necrosis of proximal tubules, vacuolation of cytoplasm and massive mononuclear inflammatory infiltrates in interstitium. Coadministration of green tea with gentamicin histologically showed renoprotective effect. Histological results were confirmed and quantified by morphometric analysis. Also in this group we measured ameliorated parameters of renal functions and antioxidative defense. SIGNIFICANCE Regenerative potential of green tea after renal injury induced by gentamicin could be explained through the decrease of oxidative stress and lipid peroxidation. Green tea is a natural antioxidant, with many health promoting effects, widely available and in accordance to that affordable. Because of the established habits, people largely consume it as a beverage. It could be beneficial in the reduction of oxidative stress and changes caused by it primarily in renal tubules and interstitium.

Beneficial effects of calcium oral coadministration in gentamicin-induced nephrotoxicity in rats.

Abstract Frequent therapeutical use of an aminoglycoside antibiotic gentamicin (GM) is limited by its nephrotoxic effects often characterized by both morphological and functional alterations of kidney leading to acute renal failure. The aim of this study was to examine the effect of dietary calcium supplementation on GM-induced nephrotoxicity in rats. Experiments were performed on 30 adult male Wistar rats divided into three groups of 10 animals each. G-group received GM intraperitoneally at a dose of 100 mg/kg; GCa-group received the same dose of GM concomitantly with 1 g/kg calcium carbonate given orally; and C-group, serving as control, received 1 mL/day of normal saline. All groups were treated during 8 consecutive days. Quantitative evaluation of GM-induced structural and functional changes of kidney was performed by histopathological, morphometrical, and biochemical analyses. Compared with control, G-group of rats were found to have diffusely and unequally thickened glomerular basement membrane with neutrophil cells infiltration. In addition, vacuolization of cytoplasm of proximal tubule cells with coagulation-type necrosis was observed. These GM-induced pathological lesions were significantly reduced in the rats of GCa-group. Morphometric analysis revealed statistically significant differences in the size of glomeruli (area, major and minor axes, perimeter), optical density, and roundness of glomeruli (p < 0.05) between G and GCa groups. Biochemical analysis showed significant elevation in blood urea and serum creatinine concentrations, whereas potassium concentration was lowered in G-group compared with the other groups (p < 0.01). It is concluded that oral supplementation of calcium during treatment with GM resulted in significant reduction of morphological and functional kidney alterations.

Bilberry: Chemical Profiling, in Vitro and in Vivo Antioxidant Activity and Nephroprotective Effect against Gentamicin Toxicity in Rats

We assessed possible protective effect of bilberry diet in rat model of nephrotoxicity. In vivo and in vitro antioxidant activity and chemical profiling of this functional food was performed. With aid of HPLC‐DAD and spectrophotometric method, 15 individual anthocyanins were quantified alongside total tannin, phenylpropanoid, and anthocyanin content. The study was conducted on four groups of rats: control, treated with only gentamicin, treated with only bilberry, and treated with both gentamicin and bilberry. Kidney function was evaluated by tracking urea and creatinine. Morphology of renal tissue and its changes were recorded pathohistologically and quantified morphometrically. Bilberry (100 mg/kg daily) showed strong nephroprotective effect against gentamicin toxicity in rats (as shown through MDA, AOPP, and catalase levels). In conclusion, the demonstrated protective activity of bilberry extract matched well with the assessed in vivo and in vitro antioxidant activity as well as with its polyphenolic content, particularly with high anthocyanin levels. Copyright

Beneficial Effects of Green Tea Extract in Gentamicin-Induced Acute Renal Failure in Rats / Povoljni efekti ekstrakta zelenog čaja na akutnu bubrežnu insuficijenciju uzrokovanu gentamicinom kod pacova

Summary The aim of this study was to investigate whether green tea extract has beneficial effect on gentamicin-induced acute renal failure. The investigation was conducted on thirty-two Wistar rats divided into four groups of 8 animals each. Control (C) group received normal saline. GT group received green tea extract orally, 300mg/kg. GM group received gentamicin intraperitoneally, 100mg/kg and GT+GM group received both gentamicin and green tea extract. Histological sections of kidney in GM group revealed necrosis of proximal tubules, vacuolization of cytoplasm and massive mononuclear inflammatory infiltrates in interstitium. Coadministration of green tea with gentamicin had renoprotective effect and showed only mild infiltrations, normal glomeruli and alleviated tubular degeneration. Analysis of biochemical parameters showed significantly higher urea and creatinine serum concentrations in GM group in comparison with C group and GT+GM group (p<0.001). Plasma lipid peroxidation biomarker MDA was significantly higher in GM group than those in C group (p<0.001), whereas the values for GT+GM group were significantly lower than MDA recorded for GM group (p<0.001). Beneficial effects of green tea on gentamicin-induced nephrotoxicity is explained through decrease of oxidative stress and lipid peroxidation.Our results indicate that green tea administration has nephroprotective effect on oxidative stress and acute renal failure caused by gentamicin. Sažetak Cilj našeg istraživanja bio je da ispitamo efekat zelenog čaja na akutnu bubrežnu insuficijenciju uzrokovanu gentamicinom. Istraživanje smo sproveli na trideset dva pacova Wistar soja koje smo podelili u četiri grupe od po 8 životinja. Kontrolna (C) grupa primala je fiziološki rastvor. GT grupa je primala oralno ekstrakt zelenog čaja u dozi od 300 mg/kg. GM grupa primala je gentamicin intraperitonealno u dozi od 100 mg/kg, a GT+GM grupa primala je zajedno gentamicin i ekstrakt zelenog čaja. Histološki preparati bubrega pacova GM grupe pokazali su nekrozu proksimalnih tubula, vakuolizaciju citoplazme i masivni mononuklearni zapaljenski infiltrat u intersticijumu. Istovremena primena zelenog čaja sa gentamicinom imala je renoprotektivni efekat i pokazala samo blage infiltrate, normalne glomerule i smanjenu degeneraciju tubula. Analiza biohemijskih parametara pokazala je statistički značajno povećanje koncentracije uree i kreatinina u GM grupi, u poređenju sa C grupom i GT+GM grupom (p<0,001). Biomarker lipidne peroksidacije u plazmi MDA bio je značajno viši u GM grupi u odnosu na C grupu (p<0,001), dok su njegove vrednosti u GT+GM grupi bile značajno niže u poređenju sa GM grupom (p<0,001). Korisni efekti zelenog čaja na gentamicinom uzrokovanu nefrotoksičnost mogu se objasniti smanjenjem oksidativnog stresa i lipidne peroksidacije. Naši rezultati ukazuju da primena zelenog čaja ima protektivni efekat na oksidativni stres i akutnu bubrežnu insuficijenciju uzrokovanu gentamicinom.

Acute Effects of Smoking on Heart Rate and Peripheral Resistance in Young Smokers

Summary Smoking has many harmful effects on human body. It is well known that smoking is one of the most important risk factors for cardiovascular diseases. Though the ingredients from cigarette smoke stimulate the release of vasoconstrictor and reduce the release of vasodilator substances, the goal of this study was to investigate the acute effects of smoking on arterial blood pressure, heart rate and blood vessel flow. The investigation was conducted on forty healthy volunteers divided into two groups of twenty non-smokers (control group), and twenty smokers (experimental group). The group of smokers was examined before and after smoking four cigarettes during one hour. Blood pressure and electrocardiograph (ECG) were measured by common methods. Brecht’s and Boucke’s methods of plethysmography were used to evaluate the peripheral circulation. There were no differences in measured systolic and diastolic blood pressure and recorded ECG between non-smokers and smokers, neither between smokers before and after smoking. However, heart rate was increased by 29.57% after smoking in comparison to the value before smoking. Evaluation of plethysmographic parameters showed that amplitude was significantly decreased. Parameters of peripheral resistance were very increased: ductility was decreased by over 20%. It can be concluded that acute smoking does not significantly affect the level of blood pressure, although it increases heart rate. The shape of plethysmograms showed decreased systolic filling and decreased diameters of blood vessels. Sažetak Pušenje ima mnogo štetnih efekata na ljudski organizam. Dobro je poznato da pušenje predstavlja jedan od najvažnijih faktora rizika za pojavu kardiovaskularnih bolesti. Sastojci dima cigarete stimulišu oslobađanje vazokonstriktivnih, a inhibišu oslobađanje vazodilatatornih supstanci. Zato smo kao cilj našeg rada postavili praćenje akutnih efekata pušenja cigareta na arterijski krvni peitisak, srčanu frekvenciju i periferni protok. Istraživanje je vršeno na grupi nepušača (kontrolna grupa) i grupi pušača (eksperimentalna grupa). Klasičnim metodama su registrovani krvni pritisak i elektrokardiogram (EKG) kod nepušača, kao i kod pušača pre i nakon pušenja četiri cigarete u vremenskom razmaku od jednog sata. Periferna cirkulacija je procenjivana upotrebom pletizmografske metode Brecht and Boucke. Naši rezultati pokazuju da nije bilo razlika u vrednostima sistolnog i dijastolnog krvnog pritiska, kao ni u EKG nalazima između nepušača i pušača. Pomenuti parametri ostaju slični i kod pušača nakon pušenja. Međutim, srčana frekvencija se nakon pušenja značajno povećava, čak za jednu trećinu (29,57%), u poređenju sa vrednostima pre pušenja. Procena pletizmograma pokazuje da se njegova amplituda smanjuje, a da se vrednosti parametara koji ukazuju na periferni otpor značajno povećavaju. Rastegljivost krvnih sudova (širina i površina pletizmograma) se smanjuje za oko 20%, što ukazuje na smanjenje srednje vrednosti dijametra krvnih sudova. Može se zaključiti da pušenje nema značajne akutne efekte na krvni pritisak, iako povećava srčanu frekvenciju. Pletizmogramski nalaz ukazuje na smanjenje sistolnog volumena i dijametra krvnih sudova.