Browsing by Author "Jayita Pal Chowdhury"

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Antiviral attributes of bee venom as a possible therapeutic approach against SARS-CoV-2 infection
(Newlands Press Ltd, 2023) Soumik Goswami; Jayita Pal Chowdhury
The unprecedented scale of the SARS-CoV-2 pandemic has driven considerable investigation into novel antiviral treatments since effective vaccination strategies cannot completely eradicate the virus. Apitherapy describes the medicinal use of bee venom, which may be an effective treatment against SARS-CoV-2 infection. Bee venom contains chemicals that are antimicrobial and stimulate the immune system to counteract viral load. The present review focuses on the use of bee venom as a possible treatment for COVID-19 and reviews studies on the pharmacodynamics of bee venom. © 2023 Future Medicine Ltd.
Effect of polybrominated diphenyl ether (BDE-209) on testicular steroidogenesis and spermatogenesis through altered thyroid status in adult mice
(Academic Press Inc., 2016) Debarshi Sarkar; Jayita Pal Chowdhury; Shio Kumar Singh
Polybrominated diphenyl ethers (PBDEs), a class of brominated flame retardants (BFRs), have been widely used in many products to minimize the risk of fire, mainly by mixing in polymer products. BDE-209, a congener of PBDEs having structural similarity with thyroid hormones, acts as an endocrine disruptor by interfering with thyroid homeostasis. However, little is known about the effect of BDE-209 exposure on testicular steroidogenesis and spermatogenesis. This study was therefore conducted in adult mice to examine the effect of BDE-209 on testicular steroidogenesis and spermatogenesis in relation to thyroid status, and to explore possible mechanism(s) of its action. Adult Parkes strain male mice were orally gavaged with 750 and 950 mg/kg BW of BDE-209 in corn oil for 35 days. Significant reductions were noted in the levels of serum total T3, T4 and testosterone in mice treated with 950 mg/kg BW of BDE-209 compared to controls; histologically, testes showed nonuniform degenerative changes in the seminiferous tubules as both affected and normal tubules were observed in the same section; further, number and viability of spermatozoa were also adversely affected in cauda epididymidis of these mice. Semiquantitative RT-PCR and western blot analyses also showed significant reductions in both testicular mRNA and protein levels of steroidogenic factor 1 (SF-1), steroidogenic acute regulatory (StAR) protein, cytochrome P450scc (CYP11A1), 3β-hydroxysteroid dehydrogenase (3β-HSD) and 17β-hydroxysteroid dehydrogenase (17β-HSD) in 950 mg dose treated-mice compared to controls. Immunohistochemical and immunoblot analyses further revealed a marked decrease in proliferating cell nuclear antigen (PCNA) positive cells in testes of 950 mg dose of BDE-209-treated mice. However, 750 mg dose of BDE-209 had no effect on the above parameters. In conclusion, our results suggest that exposure of BDE-209 to adult mice causes reduction in serum levels of thyroid hormones and altered thyroid status may partly result into impairment of testicular steroidogenesis because of down-regulated expression of SF-1, thereby causing suppression of spermatogenesis. © 2015 Elsevier Inc.
Extrapineal melatonin: A hormonal microcircuit for local adaptations
(Nova Science Publishers, Inc., 2020) Sameer Gupta; Jayita Pal Chowdhury; Chandana Haldar
The indoleamine melatonin can no more be considered as an exclusive product of the pineal gland. In the last few decades the presence of melatonin has been reported in a wide variety of organs/cells that includes carotid body, bone marrow, Harderian gland, skin, liver, gastrointestinal tract, endothelial cells, endocrine glands, cells of immune system, reproductive organs and many more. These melatonin secreting organs/cells are supposed to be a part of the 'diffuse neuroendocrine circuit' which is independent of scotoperiod for activation of its melatonin bio-synthesis machinery. The absence of circadian melatonin rhythm in these tissues suggests local melatonin to be "out of step" with its chronobiological functions. However, the remarkably high concentration might meritoriously support the protective role played by the melatonin in these tissues. The concentration of melatonin is further known to vary in a tissue specific manner thus presenting an adaptive strategy to exercise homeostatic control depending upon the physiological status of the cell/tissue. Melatonin derived from these extra-pineal sources can act in an autocrine, intracrine or paracrine manner to exert its pleiotropic actions on cellular protection and survival. The present review will focus on the physiological relevance of the emerging roles of locally produced melatonin as a modulator of intracellular relationships and cellular homeostasis. © 2021 Nova Science Publishers, Inc.
Photoperiodic regulation of ovarian steroidogenesis in a tropical rodent, Funambulus pennanti: role of melatonin and MT1
(Taylor and Francis Ltd., 2020) Jayita Pal Chowdhury; Chandana Haldar
To elucidate the role of photoperiodically modulated endogenous melatonin and its receptor MT1 in the ovary of a diurnal rodent, adult Indian palm squirrel Funambulus pennanti were exposed to Short Day (SD; 16L:8D) and Long Day (LD; 16L:8D) and compared with natural day controls (NDL; 12L:12D). Plasma 17-β estradiol level was significantly low in SD group while expression of StAR, P450SCC, 17-β HSD, and aromatase showed significant down-regulation in the ovary of squirrels maintained under SD when compared to LD and NDL groups suggesting an overall decrease in steroidogenesis. Expression of ERα in the ovary was significantly lower in SD than both LD and NDL groups, having a positive correlation with plasma estradiol level. Circulatory melatonin level was significantly high in SD-exposed squirrels, while expression of MT1R decreased in the ovary when compared to LD and NDL groups, showing a negative correlation with plasma melatonin levels. Expression of cell proliferation marker Proliferating Cell Nuclear Antigen (PCNA) was positively correlated to MT1R expression in the ovary being significantly low in SD-exposed squirrels. Our results suggest that even in tropical rodents seasonal variation in photoperiod is responsible for initiating female reproductive activities where circulatory melatonin via MT1R plays an important role. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.
Stress associated ovarian dysfunctions in a seasonal breeder Funambulus pennanti: Role of glucocorticoids and possible amelioration by melatonin
(Academic Press Inc., 2022) Jayita Pal Chowdhury; Chandana Haldar
Studies have shown that stress caused by lack of physical activity disrupts the normal pattern of glucocorticoid secretion which adversely affects the reproductive axis. We studied the effect of chronic movement restriction on ovarian responses in the Indian Palm Squirrel Funambulus pennanti, a highly active diurnal rodent. Physical restraint of squirrels induced stress that led to a significant increase in plasma cortisol, corticosterone and decreased 17β-estradiol level leading to follicular atresia. Ovarian Reactive Oxygen Species (ROS) content, lipid peroxidation (LPO), activities of superoxide dismutase (SOD) and catalase (CAT) enzymes increased in restrained squirrels. Elevated ROS increased the oxidative load that led to ovarian cell death as evidenced by increased Bax and decreased Bcl2 expression causing further decline in Aromatase and ERα proteins. To elaborate the mechanism(s) involved in stress induced glucocorticoid mediated oxidative damages to the ovary we extended our study by exposing ovaries in vitro to the synthetic glucocorticoid dexamethasone (200 μM). We observed that glucocorticoid receptor (GR) expression was significantly increased in dexamethasone treated ovaries in vitro with a decrease in expression of Nrf2 and HO-1 proteins. Melatonin supplementation (10 nM) along with dexamethasone significantly decreased ovarian ROS production, lipid peroxidation and increased antioxidant enzyme activities by improving the expression of Nrf2 and HO-1, reinstating the cellular redox homeostasis. Therefore, it can be suggested that physical restraint induced glucocorticoid and its receptor activation interfered with the ovarian antioxidant defense mechanism. Melatonin via its receptor MT1 significantly alleviated ovarian damages acting as a cytoprotective agent. © 2021 Elsevier Inc.