Impact of thermal stress on expression dynamics of HSP60 in cardiac fibroblast cells of goat

Transcription pattern of key molecular chaperones in heat shocked caprine cardiac fibroblasts

The present study was attempted to unveil the impact of heat stress on transcription pattern of major heat shock response genes in caprine cardiac fibroblasts. Cardiac tissues (n = 6) were collected and primary cardiac cell culture was done. Cultured cardiac fibroblasts were kept in an atmosphere of 5% CO2 and 95% air at 38.5 °C. Cardiac cells achieved 70-75% confluence after 72 hours of incubation. Heat stress was induced on confluent cardiac fibroblasts at 42 °C for 0 (control), 20, 60, 100 and 200 min. Quantitative RT-PCR for β2m (internal control), HSP60, HSP70, HSP90, and HSP110 was done and their transcription pattern was assessed by Pfaffl method. HSP60, HSP90, and HSP110 transcription did not differ at 20 min, up-regulated (p < 0.05) from 60 to 200 min and registered highest at 200 min of heat exposure. HSP70 transcription was gradually escalated (p < 0.05) time dependently from 20 to 200 min and reached zenith at 200 min of heat exposure. Differential induction in transcription of key molecular chaperones at various durations of heat exposure might reduce cardiac fibroblasts apoptosis and thus could maintain cardiac tissue function during heat stress.

Hyper-transcription of heat shock factors and heat shock proteins safeguard caprine cardiac cells against heat stress

The present study was undertaken to document the transcriptional abundance of heat shock factors and heat shock proteins and their role in survivability of caprine cardiac cells during heat stress. Cardiac tissues were collected from different goats (n = 6) and primary cardiac cell culture was done in an atmosphere of 5% CO₂ and 95% air at 38.5 °C. Cardiac cells accomplished 70-75% confluence after 72 h of incubation. Confluent cardiac cells were exposed to heat stress at 42 °C for 0 (control), 20, 60, 100 and 200 min. Quantitative RT-PCR for β2m (internal control), heat shock factors (HSF1, HSF2, HSF4, HSF5), heat shock proteins (HSP10, HSP40), and Caspase-3 was done and their transcriptional abundance was assessed by Pfaffl method. Transcriptional abundance of HSF1, HSF2, and HSF4 did not change at 20 min, increased (P < 0.05) from 60 to 200 min and reached zenith at 200 min of heat exposure. However, transcriptional abundance of HSF5 was gradually escalated (P < 0.05) from 20 to 200 min and registered highest at 200 min of heat exposure. Transcriptional abundance of HSP10 and HSP40 followed an similar pattern like that of HSF5. Transcriptional abundance of Caspase-3 was significantly down-regulated at 200 min of heat exposure. It could be speculated that over-expression of HSFs and HSPs might have reduced Caspase-3 expression at 200 min of heat exposure suggesting their involvement in cardiac cells survival under heat stress. Moreover, hyper-expression of HSFs and HSPs could maintain the integrity and endurance of cardiac tissues of goats under heat stress.

Thermoregulatory reactions of female buffaloes raised in the sun and in the shade, in the climatic conditions of the rainy season of the Island of Marajó, Pará, Brazil

Buffaloes are well-adapted to hot, humid climates and muddy terrain, however they show signs of thermal discomfort when exposed to direct sunlight due to their specific structural features such as dark skin, small number of sweat glands/skin area and thick skin. Epidermis layer of the skin, making heat dissipation difficult. The study aimed to evaluate the thermal comfort of female buffaloes raised in traditional and silvopastoral systems, on the island of Marajó, Pará, during the rainy season of the year. The experiment was carried out in Cachoeira do Arari, Retiro Grande, Marajó, Pará (00°55'37.814424”S 48°43'48.143060”W). Twenty female Murrah buffaloes, aged between 2 and 3years and average weight of 282 ± 29 kg, were used. They were fed on pasture and divided into two groups: WS group (with shade) and NS group (without shade). The WS group (n = 10) remained grazing in a silvopastoral system, with access to the shade of red Jambeiro (Syzygium malaccense) trees. The NS group (n = 10) was kept in grazing, in a traditional system, without access to the shade of trees or shades. The physiological variables rectal temperature (RT), respiratory rate (RR) and body surface temperature (BST) (forehead, left side of the thorax and left flank) were measured at 6:00, 10:00, 14:00, 18:00, and 22:00 h. At the same times, data on air temperature, relative air humidity, wind speed (WSP), solar radiation (SR) and Temperature and Humidity Index (THI) were also recorded. THI, WSP and SR were higher at 14:00 h (P < 0.05). At 10:00, 14:00, and 18:00 h there was difference of RT between treatments (P < 0.05), where animals of the NS group had the highest values. In the NS group, the highest value of RT was observed at 14:00 h (39.38 ± 0.43°C), when THI and SR were higher. At 10:00 and 14:00 h, BST was higher in the NS group (p < 0.05), of 34,55 ± 1.03 and 35.35 ± 1.51°C, respectively, and both groups had the highest value of BST at those same times. There was difference of the RR between treatments at 10:00 h and 14:00 h (p < 0.05), where the highest values were found in the NS group (33.71 ± 7.58 e 50.40 ± 18.41 mov./min., respectively). Even in the rainy season of the year, the climatic conditions of Ilha do Marajó are unfavorable to the welfare of buffaloes, especially at 2:00 pm, when the SR is higher. Thus, the use of the system with access to shade, such as silvopastoral, is recommended, in order to provide greater thermal comfort to animals and improve their productivity.

Behavioural, physiological, neuro-endocrine and molecular responses of cattle against heat stress: an updated review

The negative impact of heat stress on cattle growth, development, reproduction and production has been quite alarming across the world. Climate change elevates earth surface temperature which exacerbates the wrath of heat stress on cattle. Moreover, cattle in tropical and sub-tropical countries are most commonly affected by the menace of heat stress which severely wane their production and productivity. In general, cattle exhibit various thermoregulatory responses such as behavioural, physiological, neuro-endocrine and molecular responses to counteract the terrible effects of heat stress. Amongst the aforementioned thermoregulatory responses, behavioural, physiological and neuro-endocrine responses are regarded as most conventional and expeditious responses shown by cattle against heat stress. Furthermore, molecular responses serve as the major adaptive response to attenuate the harmful effects of heat stress. Therefore, present review highlights the significance of behavioural, physiological, neuro-endocrine and molecular responses which act synergistically to combat the deleterious effects of heat stress thereby confer thermo-tolerance in cattle.

Thermoregulatory responses in riverine buffaloes against heat stress: An updated review

High heat and humidity stress have been a perpetual perilous for the buffalo's production and productivity in tropics and subtropics including India. Productive potential of livestock's species including buffaloes is maximum with in thermo-neutral zone (TNZ) and if ambient temperature exceeds TNZ and upper critical temperature expose livestock's to heat stress conditions. For decades, heat stress has been the prime factor to plummet buffalo's growth, development, reproduction and production in tropics and subtropics including India. In general, buffaloes are homeotherms and known as temperature regulators as they resist the variations in ambient temperatures. Generally, buffaloes like other livestock's display amalgamation of thermoregulatory responses to withstand the changes occurred in their micro and macro environment. These thermoregulatory responses are behavioural, physiological, neuro-endocrine and molecular responses acting synergistically to counteract the deleterious effects of heat stress. Amidst all responses, molecular responses play major role to confer thermo-tolerance through expression of highly conserved family of proteins known as heat shock proteins (HSPs). Despite of these thermoregulatory responses, heat stress prodigiously muddles buffalo's production and productivity. The present review highlights the thermoregulatory responses manifested by riverine buffaloes against heat stress.

Significance of molecular chaperones and micro RNAs in acquisition of thermo-tolerance in dairy cattle

Ambient temperature is considered as the major abiotic factor which regulates body physiological mechanisms of all living creatures across the globe. Variation in ambient temperature which emulates thermoneutral zone culminates in heat stress. Heat stress has been emerged as major ultimatum to livestock's growth, development, production and reproduction across the world. Livestock's responds to the heat stress via different mechanisms such as behavioral, physiological, biochemical, endocrine and molecular mechanisms. Amongst the aforementioned mechanisms, molecular mechanism plays crucial role to achieve thermo-tolerance via expression of highly conserved family of proteins known as heat shock proteins (HSPs) across livestock species. HSPs serve as molecular chaperones to ameliorate the menace of heat stress in domestic species. In addition, microRNAs are small non-coding RNA which down regulates post-transcriptional gene expression by targeting various HSPs to regulate the thermoregulatory responses in livestock species. Despite of thermal adaptation mechanisms, heat stress breaches animal body homeostasis thereby depresses their production and productivity. Therefore, veterinary researches have been targeting to explore different repertoire of HSPs and microRNAs expression to counteract the rigors of heat stress thereby confer thermo-tolerance in livestock species. The present review highlights the significance of molecular chaperones and microRNAs in the acquisition of thermo-tolerance in dairy cattle.