Fig 1: Schematic of the in vivo experiments. Following quarantine and acclimatization, baseline readings of the employed pain parameters were recorded for all animals. Thereafter, MIA was injected into the right knee joints of all animals except those in the NC. Rats in NC group were administered saline by intra-articular route. Seven days post-MIA injection, animals were assessed for the development of mechanical hyperalgesia for randomization to receive different designated treatments, thenceforth. Rats received either indomethacin (2.5 mpk/day) or three different doses of PN-G (104, 312 and 936 mpk/day). Animals in NC and DC groups received methylcellulose. Mechanical hyperalgesia and tactile allodynia were recorded at an interval of every 3–4 days until day 26, when the animals were additionally subjected to radiological examination. On day 27, animals were euthanized and blood was collected for measurement of the serum osteoarthritic biomarker, COMP. The right knee joints were harvested for histopathological evaluation through H-E and Safranin-O staining.