ABSTRACT
This study involved cerebroprotective potential of aloe emodin (AE) by in silico molecular docking analysis against various cerebrotoxic proteins followed by in vivo activity on multiple occlusions and reperfusion of bilateral carotid arteries (MO/RCA) induced cerebral injury in experimental rats. Molecular docking studies were carried out to evaluate the binding affinity (or binding interaction) between AE and various proteins involved in apoptosis such as caspase-3 (CASP3) and Bcl-2-associated X protein (BAX), and proteins involved in inflammation such as interleukin-6 (IL-6), tumor necrosis factor α (TNF α), nitric oxide synthase (NOS), acid-sensing ion channel (ASIC) and glutamate receptor (GR) involved in cerebral stroke, and results were compared with that of standard drugs, minocycline, quercetin, and memantine. Cerebral ischemic reperfusion induced by MO/RCA was assessed for 10 mins reperfusion period as one cycle, and the experiment was conducted for up to 3 cycles in rats. After completion of 3 cycles, the rats were subjected to ethically acceptable animal euthanasia followed by isolation of the brains which were studied for the size of cerebral infarction, and biochemical parameters such as glutathione (GSH), malondialdehyde (MDA), catalase (CAT) were estimated from the brain homogenate. Further, histological studies were done to study neuronal contact. Results of molecular docking indicated that the AE exhibited interaction with active sites of cerebrotoxic proteins usually involved in protein functions or cerebrotoxicity. Biochemical results showed that in the untreated brain, MDA levels increased significantly, and decreased GSH and CAT levels were observed when compared to MO/RCA group, while treated rats showed a decrease in the levels of MDA and an increase in GSH and CAT levels as compared to MO/RCA rats. In comparison with sham rats and normal rats, histopathological analysis revealed neuronal damage in MO/RCA surgery rats which manifested as decreased intact neurons. However, treatment with AE 50 mg/kg b.wt. restored contact between neuronal cells. It can be concluded that AE showed cerebroprotective effect on RO/RCA with promising inhibition of cerebrotoxic proteins (apoptotic and neuroinflammatory) as evident from molecular docking studies. The cerebroprotective potential of AE could be due to its anti-inflammatory, antioxidant, and antiapoptotic principles.
ABSTRACT
Salinity severely affects the growth/productivity of rice, which is utilized as major staple food crop worldwide. PDH45 (pea DNA helicase 45), a member of the DEAD-box helicase family, actively provides salinity stress tolerance, but the mechanism behind this is not well known. Therefore, in order to understand the mechanism of stress tolerance, sodium ion (Na(+)), reactive oxygen species (ROS), cytosolic calcium [Ca(2+)]cyt and cell viability were analyzed in roots of PDH45 transgenic-IR64 rice lines along with wild-type (WT) IR64 rice under salinity stress (100mM and 200 mM NaCl). In addition, the roots of salinity-tolerant (FL478) and susceptible (Pusa-44) rice varieties were also analyzed under salinity stress for comparative analysis. The results reveal that, under salinity stress (100mM and 200 mM NaCl), roots of PDH45 transgenic lines accumulate lower levels of Na(+), ROS and maintain [Ca(2+)]cyt and exhibit higher cell viability as compared with roots of WT (IR64) plants. Similar results were also obtained in the salinity-tolerant FL478 rice. However, the roots of WT and salinity-susceptible Pusa-44 rice accumulated higher levels of Na(+), ROS and [Ca(2+)]cyt imbalance and lower cell viability during salinity stress, which is in contrast to the overexpressing PDH45 transgenic lines and salinity-tolerant FL478 rice. Further, to understand the mechanism of PDH45 at molecular level, comparative expression profiling of 12 cation transporters/genes was also conducted in roots of WT (IR64) and overexpressing PDH45 transgenic lines (L1 and L2) under salt stress (24h of 200 mM NaCl). The expression analysis results show altered and differential gene expression of cation transporters/genes in salt-stressed roots of WT (IR64) and overexpressing transgenic lines (L1 and L2). These observations collectively suggest that, under salinity stress conditions, PDH45 is involved in the regulation of Na(+) level, ROS production, [Ca(2+)]cyt homeostasis, cell viability and cation transporters in roots of PDH45 transgenic-IR64 rice and consequently provide salinity tolerance. Elucidating the detailed regulatory mechanism of PDH45 will provide a better understanding of salinity stress tolerance and further open new ways to manipulate genome to achieve higher agricultural production under stress.
