Progress on the role of Traditional Chinese Medicine in inflammatory injury of COVID-19

Novel coronavirus pneumonia is an infectious respiratory disease induced by a novel coronavirus, named COVID-19. At present, novel coronavirus pneumonia is widely spread around the world, with the characteristics of long incubation time, strong contagion, rapid progress, and high fatality rate. Inflammatory storm, also known as cytokine storm, has been found to play an important role in COVID-19 induced lung injury, and is believed to be one of the core pathological factors leading to exacerbation and even death of novel coronavirus pneumonia patients. It is found that over-expression and release of pro-inflammatory cytokines such as IL-6 will lead to self-attack and aggressive inflammatory response, and finally cause tissue damage. Studies have shown that the intervention of inflammatory injury may be one of the important mechanisms that contribute to therapeutic effect of Traditional Chinese Medicine against COVID-19. Clinical studies found that early intervention with Traditional Chinese Medicine in novel coronavirus pneumonia patients could significantly alleviate signs and symptoms, shorten course of the disease, decrease possibility of the patients progressing into severe stage, slow or even block the outbreak of inflammatory storm in the patient's body, improve cure rate, reduce mortality, relieve sequelae, and promote the recovery of the patients in the recovery period. Through analyzing the representative prescription of Traditional Chinese Medicine in the Eighth Edition of the Diagnosis and Treatment Scheme for COVID-19, we found the regulation on the inflammatory injury by Traditional Chinese Medicine is realized in a multi-target manner. On the one hand, some Chinese Medicines are exhibited with direct effects against proliferation of the virus; on the other hand, some Chinese Medicines are shown with ability to re-balance the immune system via regulating function of immune cells, decreasing production of pro-inflammatory cytokines while increasing secretion of anti-inflammatory mediators. The epidemic of novel coronavirus pneumonia has not yet ended, and the world is still under the attack of COVID-19 virus. Although previous studies have found that certain ingredients in Traditional Chinese Medicine, such as astragalin, astragaloside IV, platycodin and wogonin, etc., as well as Traditional Chinese Medicine prescription including Qingfei Paidu Decoction, Huashibaidu Decoction, etc., can control inflammatory injury, their specific mechanism and the material basis still need to be studied in depth. On the other hand, the objective indicator of Traditional Chinese Medicine for patients with different syndromes still needs to be further clarified to facilitate its promotion in clinic. The integration of Traditional Chinese Medicine and western medicine has been proved to be more effective in inhibiting the development of novel coronavirus pneumonia, but the role of Traditional Chinese Medicine in the integrative therapy still needs to be further explored. Although there is still a lot of work to be carried out, the advantage of early intervention with Traditional Chinese Medicine against COVID-19 virus has been verified in both clinical and experimental studies. This paper aims to review mechanism and treatment strategy of Chinese Medicine on COVID-19 induced inflammation, and provide references for researchers in related area.