In vitro investigation of the neuroprotective potential of boric acid in a rotenone-induced parkinson

Objective: Parkinson'sdisease (PD) represents a multifaceted neurodegenerative disorder characterisedby the progressive degeneration of dopaminergic neurons, ultimately resultingin neurodegeneration. The hallmark pathological features of PD encompass thereduction of dopaminergic neurons in the substantia nigra pars compacta and theaccumulation of misfolded α-synuclein within cytoplasmic inclusions known asLewy bodies. Rotenone, a naturally occurring toxin produced by tropical plants,possesses the capacity to penetrate the blood-brain barrier. Upon neuronalentry, it impedes proteasome activation, instigating α-synucleinphosphorylation, aggregation, Lewy pathology formation, and subsequentdegeneration of nigrostriatal dopaminergic neurons. Boric acid (BA),representing the primary form of boron in human tissues and bodily fluids,assumes a pivotal role. A deficiency of BA in the human body is associated withdiminished motor and cognitive functions. The aim of our study is to examine the possible protective effect of BAwithin a Rotenone-induced Parkinson's disease model established in the SH-SY5Yhuman neuroblastoma cell line, serving as an in vitro experimentalparadigm.Methods: Thecytotoxic effect of BA was determined by MTT experiment as a result of thecombined application of 200µM, 100 µM, 50 µM, 20 µM BA and 50 µM Rotenoneconcentrations to the SH-SY5Y cell. Gene expression levels of signallingpathways involved in the cytotoxicity of SH-SY5Y cells of the Rotenone, BA, andRotenone + BA groups were investigated by quantitative reverse transcriptasepolymerase chain reaction (RT-qPCR) and changes in protein expressiondetermined by the Western Blot method.Results: The MTTexperiment revealed that the viability of the PH model generated with 50 µMRotenone was 64.58%, whereas the viability of the PH model generated with 200µM BA was 116.36%, and a significant proliferation was observed. This specificdosage was selectively used for RT-qPCR and Western blot analyses. Notably, theco-administration of 50 µM Rotenone with 200 µM BA exhibited a markedattenuation of apoptotic processes, as evidenced by a notable reduction in theBAX/BCL-2 pro-apoptotic mRNA ratio, displaying a 0.54-fold change relative tothe Rotenone-only group. Conclusion: Consequently,these findings lead to the inference that boric acid (BA) may exert aneuroprotective effect.Keywords:Apoptosis, boric acid, neuroprotective, Parkinson's disease, rotenone.