Effects of melatonin on the histomorphometry of the pancreas, liver and kidney of rats on antiretroviral treatment

Truter, Danelle (2017-12)

Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Biomedical Sciences: Anatomy and Histology

Thesis (MSc)--Stellenbosch University, 2017

Thesis

ENGLISH ABSTRACT : The administration of combination antiretroviral therapy (cART) in HIV positive patients has shown to cause side histologically observable effects in the pancreas, liver and kidneys. These conditions include acute pancreatitis, cellular injury, oxidative stress, hepatotoxicity and nephrotoxicity, which presents as inflammation and cellular injury. Melatonin has been successful in the prevention and reduction of inflammatory markers, oxidative stress and cellular damage, and has been observed as a treatment option in various conditions. The aim of this study was to evaluate the observable morphometric changes caused by cART as well as the potential therapeutic effects of melatonin on the pancreas, liver and kidney of the control (C/ART-), cART (C/ART+), melatonin (C/M+) and cART and melatonin (ART+/M+) groups in the absence of HIV in a rat model. Tissue samples (N=40) of the ventral part of the pancreas, the median lobe of the liver and the right kidney male Wistar rats were collected. The blood samples (n=37) were collected from the abdominal aorta after euthanasia. Samples of the pancreas, liver and kidney were stained with haematoxylin and eosin (H&E) and evaluated for histopathology. The pancreas was labelled with anti-insulin and anti-glucagon to determine α- and β-cell areas in the pancreatic islets. Blood samples were collected for liver enzyme tests to evaluate hepatotoxicity. The kidneys were stained with periodic acid Schiff (PAS) and the area, perimeter, diameter and radius of 30 renal corpuscles, with their associated glomeruli and 90 proximal convoluted tubules (PCTs) were measured per rat. The pancreas, liver and kidney showed no significant histologically observable changes in histology. The mean islets per mm2 in the pancreas was significantly higher in the C/M- group than in the C/ART- and ART+/M+ groups. Melatonin stimulated the abundance of pancreatic islets and thus indirectly the availability of α-cells. The haemoglobin value in the C/ART+ group was significantly higher than in the C/ART- group, which indicates that the mechanism in which cART increases serum haemoglobin is possibly still active in the absence of immune compromise. The C/M+ group showed a decrease in serum lipaemia compared to the C/ART- group, due to melatonin’s its inhibitory effect on peroxidation of cellular lipids by free radicals. In the kidneys, all parameters of the renal corpuscle were significantly lower in the C/ART+ and C/M+ groups compared to the C/ART- group. In the glomeruli, some parameters were significantly lower in the C/ART+ group compared to the C/ART-, C/M+ and ART+/M+ groups. The renal space was significantly decreased in the C/ART+, C/M+ and ART+/M+ groups. All parameters of the PCTs were significantly decreased in the C/ART+ group compared to the C/ART- group. All the components of the nephron were affected by cART, which may have caused tubular dysfunction, cellular damage and a decreased estimated glomerular filtration rate (eGFR). In conclusion, cART and melatonin each affected the histomorphometry of the pancreas, liver and kidney in a rat model without immune compromise. This should be considered when medication is prescribed to patients with HIV, specifically in patients with susceptibility to renal injury.

AFRIKAANSE OPSOMMING : Kombinasie antiretrovirale middels (kART) veroorsaak waarneembare veranderinge in die histologie van die pankreas, lewer en niere van menslike immuniteitsgebreksvirus (MIV)-positiewe patiënte. Hierdie toestande sluit akute pankreatitis, oksidatiewe stres, hepatotoksisiteit en toksisiteit van die niere in, wat as inflammasie en sellulêre skade voorkom. Melatonien voorkom en verminder inflammatoriese merkers, oksidatiewe stres en sellulêre skade en word vir verskeie toestande as behandelingsopsie oorweeg. Hierdie studie het ten doel gehad om die waarneembare morfometriese veranderinge in die pankreas, lewer of niere wat versoorsaak word deur kART of melatonien te vergelyk tussen ‘n kontrole (K/ART-) groep, kART (K/ART+) groep, melatonien (K/M+) groep en ‘n kART en melatonien (ART+/M+) groep in die afwesigheid van MIV in 'n rotmodel. Weefselmonsters (N=40) vanaf die ventrale deel van die pankreas, die mediane lob van die lewer en die regter nier en bloedmonsters (n=37) vanaf die abdominale aorta is geneem van manlike Wistar rotte. Die pankreas-, lewer- en nierweefsels is deur hematoksilien en eosien (H&E) gekleur vir die evaluering van histopatologie. Die pankreas is ook gemerk deur anti-glukagon en anti-insulien om die α- and β-selle, onderskeidelik, in die pankreatiese eilande te identifiseer. Toksisiteit van die lewer is getoets deur die lewerensieme te evalueer. Die niere is gekleur deur periodieke suur en Schiff (PAS) om die area, omtrek, deursnee en radius van 30 renale liggaampies en hul glomeruli, asook 90 proksimale kronkelbuise per rot te meet. Geen beduidende verskille is waargeneem in die histologie van die pankreas, lewer en nier in enige van die vier groepe nie. Die gemiddelde pankreatiese eilandjies per mm2 was beduidend hoër in die K/M+ groep in vergelyking met die K/ART- en ART+/M+ groepe. Melatonien het die hoeveelheid eilandjies vermeerder en dus indirek die beskikbaarheid van α-selle in die pankreas. Hemoglobien in die K/ART+ groep was beduidend hoër as die K/ART- groep, wat moontlik aandui dat die meganisme waarmee kART hemoglobien in MIV-positiewe individue vermeerder, steeds aktief is in die afwesigheid van immuniteitsgebrek. Die lipiedinhoud in die bloed van die K/M+ groep was beduidend laer as in die K/ART+ groep, wat kan aandui dat melatonien lipiedafbraak, wat deur vrye radikale gestimuleer word, onderdruk. Al die komponente van die renale liggampies was beduidebd laer in die K/ART- en K/M+ groepe in vergelyking met die K/ART- groep. In die glomeruli, is verskeie komponente beduidend verlaag in die K/ART+ groep in vergelyking met die K/ART-, K/M+ en ART+/M+ groepe. Die renale spasie was ook beduidend kleiner in die K/ART+, K/M+ en ART+/M+ groepe in vergelyking met die K/ART- groep. Al die komponente van die proksimale kronkelbuise was beduidend laer in die K/ART+ groep in vergelyking met die C/ART- groep. Al die komponente van die nefron is deur kART beïnvloed, hetsy deur tubulêre disfunksie of sellulêre skade, wat kan lei tot ‘n verminderde beraamde glomerulêre filtrasietempo (bGFT). Ten slotte het cART en melatonien elk die histomorfometrie van die pankreas, lewer en nier in 'n rotmodel sonder immuniteitsgebrek verander. Dit moet in ag geneem word wanneer medikasie voorgeskryf word aan pasiënte met MIV, spesifiek in pasiënte wat sensitief is vir nierbesering.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/102796
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