EFFECT OF EXOGENOUS MELATONIN ADMINISTRATION ON EXPRESSION PATTERNS OF SELECTIVE AQUAPORIN GENES IN HEAT STRESSED BUBALINE PERIPHERAL BLOOD MONONUCLEAR CELLS
Loading...
Files
Date
2023-08
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
SRI VENKATESWARA VETERINARY UNIVERSITY, TIRUPATI - 517 502. (A.P.) INDIA
Abstract
The present study was designed to evaluate the effect of exogenous melatonin
administration on heat stress (HS) amelioration in buffaloes during summer season.
Fifteen adult Murrah buffaloes were randomly selected from Livestock Farm Complex
(LFC), NTR College of Veterinary Science, Gannavaram, Andhra Pradesh. The study
was conducted during the months of May - July 2022. The animals were divided into
three groups, Group-1: (GI, Control n=5), Group-2: (GII, n=5 Melatonin @18mg/50 kg
bwt.
Subcutaneously
single
administration)
and
Group-3:
(GIII,
n=5
Melatonin@18mg/50 kg b wt. subcutaneously twice at fortnight interval. The AT and RH
were recorded throughout the study period and THI was calculated. Physiological
parameters like RT, RR and PR were recorded daily at 1:00 PM throughout the study
period. Two aliquots of blood sample (whole blood with anticoagulants and blood with
clot activators for serum isolation) were collected from all the 15 animals in weekly
interval for seven weeks. An aliquot of whole blood was directly used for analysis of
haematological parameters (TEC, TLC, Hb and PCV) and blood glucose, while the
remaining aliquot was used for separation of PBMC and subsequent RNA isolation for
gene expression studies of HSP90 and selective aquaporins (AQP1, AQP8 and AQP11).
Blood with clot activators was processed to separate serum, for estimation of biochemical
parameters (total protein, albumin, cholesterol, ALT and AST).
The THI value above 78 was observed throughout the study period indicating that
the animals were under HS. The mean±SE values of RT, RR and PR didn’t vary
significantly (p>0.05) between control and melatonin treated buffaloes The mean±SE
values of haematological parameters didn’t vary significantly (p>0.05) between control
and melatonin treated buffaloes and no significant difference (p>0.05) was observed
among all the weeks of our study period.
The mean±SE values of total protein and albumin did not vary significantly
(p>0.05) between control and melatonin treated buffaloes and no significant (p>0.05)
difference was observed among all the weeks. The blood glucose levels were significantly
(p<0.05) higher in GIII compared to control in week 6 and in overall mean. The mean
cholesterol concentration was significantly (p<0.05) higher in GIII compared to control
during week 5, 6 and in overall mean. The AST levels were significantly (p<0.05) lowered
in GIII compared to control in all the weeks and also in overall mean. The ALT levels
were significantly (p<0.05) lowered in GIII during week 5, week 6 and in overall mean
compared to control. The mean cortisol levels were significantly (p<0.05) lowered in GIII
compared control during week 4, 5, 6 and also in overall mean.
The relative mRNA expression of HSP90 and AQP8 were significantly (p<0.05)
upregulated on week 2 and 3 in GII and on week 2, 3, 4 and 5 in GIII compared to control.
Further, the overall expression of HSP90 was significantly (p<0.05) upregulated in
melatonin treated animals compared to control. Whereas for AQP8 overall expression
was significantly (p<0.05) upregulated in GIII compared GII to control. There was no
significant (p>0.05) difference in the mRNA expression of AQP1 and AQP11 between
control and melatonin treated groups (GII and GIII) during all the weeks of the study and
also in overall. Increased expression of HSP90 in melatonin treated group compared to
control in our study suggests the role of melatonin in prevention of abnormal protein
aggregation and misfolding of proteins caused due to oxidative stress. The increase in
expression of AQP8, a peroxyporin in melatonin treated group establishes the role of
melatonin in facilitating H2O2 diffusion and efflux of other free radicals generated due to
oxidative stress induced by heat stress. A THI of above 78 throughout the study period is
indicative of heat stress in animals. It can be concluded from our study that Melatonin
administration can substantially ameliorate the effects of heat stress in buffaloes as by
altering biochemical parameters (glucose, cholesterol, AST, ALT and cortisol) and
further dynamically altering expression of HSP90 and AQP8 genes.