TL15 Peptide of Sulphite Reductase from Spirulina, Arthrospira platensis Exhibited Anti-inflammatory and Antioxidant Defence Role in CuSO4-Stressed Zebrafish Embryo Through Pro-inflammatory Cytokine and Glutathione Redox Mechanism

CuSO4 was used and created an in-vivo inflammatory model of a zebrafish embryo for drug testing in this work. In our study, molecular docking was performed to check the possible polar interaction with the peptide, TL15 of sulphite reductase derived from spirulina (Arthrospira plantensis) and the COX-2, which is predicted to have anti-inflammatory activity. In-vitro anti-inflammatory activity was performed on human erythrocytes, and the potential activity of TL15 peptide was in a concentration-dependent manner. We further investigated the technique for evaluating the anti-inflammatory effects of TL15. To produce acute inflammation, the zebrafish (Danio rerio) larvae were treated with CuSO4 at 2 μM and toxicity analysis were done at 0–96 hpf. The effect of TL15 was analysed upon treatment to CuSO4 induced larvae at dose-dependent manner (10–80 μM) and exhibited a gradual reduction in oxidative stress at 80 μM TL15. Macrophages were monitored using neutral red labelling after CuSO4 stimulation; as the major end-point, larval mortality was employed. RT-PCR was used to assess the expression level of important cytokines implicated in the inflammatory response, such as COX-2, TNF-α, IL-1β and IL-10. Within 24 h, CuSO4 increased mortality in a dose-dependent process. The increment in the inflammatory response due to CuSO4 induction in zebrafish larvae was demonstrated by analysing the COX-2, IL-1β, IL-10 and TNF-α expression. In addition, we also investigated the reactive oxygen species scavenging activity of TL15 on CuSO4 induced larvae by analysing the GST and GPX expression levels in the zebrafish embryo. Overall, TL15 of sulphite reductase was found to have a potent anti-inflammatory activity by scavenging the free radical productions.