SERUM PROFILING AND TISSUE EXPRESSION PATTERN OF SIALYLTRANSFERASE IN PIGS EXPERIMENTALLY INFECTED WITH TRYPANOSOMA BRUCEI BRUCEI

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Date
2021-05
Authors
ATATA, Jamila Abdulhamid
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Abstract
African trypanosomiasis (AT) is a devastating disease that causes mortality in both man and animals with anaemia being the most consistent complicating factor. The role of increased activity of sialyltransferase (ST) has been advanced in the recovery from anaemia or stabilization of red blood cell mass in trypanosome-infected animals. This study was therefore aimed at determiningthe serum profiles and tissue expressionpattern of sialyltransferase in serum and tissues of pigs experimentally infected with Trypanosoma bruceibrucei (T. b. brucei) with the view to unraveling the role of sialyltransferase activity and tissue expression of ST3Gal1 and ST6Gal1 in the recovery from anaemia of porcine trypanosomiasis. Ten (10) apparently healthy pigs assigned to T. b. brucei-infected (n = 5) and control non-infected (n = 5) groups were used for this experiment. Parasitaemia, body temperature, haematological values, the concentrations of erythrocyte surface sialic acid (ESSA) and free serum sialic acid (FSSA) as well as activities of neuraminidase and sialyltransferase (ST) were determined on a daily basis for a period of 21 days. Body weights were also determined on weekly basis. The mean thyroid gland ST activities and the expression levels of ST3Gal1 and ST6Gal1 in the liver and kidneys were determined at the termination of the experiment. Clinical trypanosomiasis was established in the infected pigs as early as day 3 post-infection (PI); with all pigs becoming parasitaemic by day 5 PI. The parasitemia observed was associated with a gradual and progressive drop in the mean PCV valuesfrom 41.401.33 % to a minimum value of 19.40  1.66 % recorded on day 13 PI. The mean ESSA concentrationin T. b. brucei infected pigs droppedsignificantly (P < 0.05) below normal values from day 6 PI, 3 days after parasites were first detected in their blood and this was then followed by progressive risefrom day 14 to stabilize with occasional surges in its value until the termination of the experiment. Conversely, the FSSA concentration increased significantly (P < 0.05) from day 7 to reach a peak level on day 11 PI. This was accompanied by an apparent but fluctuating decrease to stabilize on day 16 until the termination of the experiment. A significant (P < 0.05) rise in neuraminidase activity was observed as early as day 7 with peak level reached on day 11 which was followed by a fluctuating decrease to stabilize at a near pre-infection value on day 14 and remained so until termination of the experiment. Meanwhile, increase in mean serum sialyltransferase activity occurred from day 6 PI and attained a significant level (P < 0.05) on day 16 and this was then followed by non-significant (P > 0.05) fluctuations which were sustained until the termination of the experiment. Similarly, thyroid tissue sialyltransferase activity of the infected pigs was significantly increased. There was a strong relationship between sialyltransferase activity and parasitemia (r = 0.5); packed cell volume (r = -0.8); decrease in free serum sialic acid concentration (r = -0.7); increase in erythrocyte surface sialic acid concentration (r = 0.8) and decrease in neuraminidase activity (r = 0.4). The mRNA expression of Trypanosoma brucei brucei-infectedand (non-infected) controlderived kidney and liver genes showed that hepatic ST6Gal 1, Renal ST6Gal 1, Hepatic ST3Gal 1 and Renal ST3Gal 1 gene expression were significantly (P < 0.0001) upregulated (41.87-fold; 19.17-fold; 15.16-fold; and 5.00-fold respectively) in the infected pig compared to the control. It was concluded from the findings in this study that serum sialyltransferase activity and increased tissue expression of ST3Gal1 and ST6Gal1 played a pivotal role in the stabilization of erythrocyte mass by the process of resialylation of desialylated red blood cells thereby promoting recovery of the red blood cells in trypanosome-infected animals. The tissue expression of ST3Gal1 and ST6Gal1 in T. b. brucei-infected pigs reported for the first time in this study could serve as a novel drug development tool that could be explored for enhancing recovery from anaemia of trypanosomiasis in both animals and man. It was therefore recommended that the expression of serum ST3Gal1 and ST6Gal1 be investigated, further in trypano-tolerant breeds of animals to determine the role of these genes in pathogenesis of trypanosomiasis
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A DISSERTATION SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF DOCTOR OF PHILOSOPHY IN VETERINARY PATHOLOGY DEPARTMENT OF VETERINARY PATHOLOGY, AHMADU BELLO UNIVERSITY, ZARIA NIGERIA
Keywords
SERUM PROFILING,, TISSUE EXPRESSION PATTERN,, SIALYLTRANSFERASE,, PIGS EXPERIMENTALLY INFECTED,, TRYPANOSOMA BRUCEI BRUCEI.
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