A Hidden System for Superoxide Disposal
Superoxide is widely implicated in stress, diseases and aging as a metabolic waste. It is macroscopically self-evident that harmless wastes requires a system including processes of collection, transportation, storage and treatment for an efficient and effective disposal, and harmful wastes demand even much more sophisticated one. As a detrimental metabolic waste, superoxide is never known to be accommodated with such a disposal system except the neutralization by various antioxidant mechanisms, which is random rather than systematical.
We encountered this hidden system by complete accident when we found that the topical application of TAT-SOD, an intracellular superoxide quenching enzyme on certain facial parts could instantly mitigate rhinitis. It reminded us of acupuncture meridians which are mysterious channels linking different parts of the body to pass the effect from one site to another, and prompted us to correlate the mysterious meridians with the intracellular superoxide anion.
To visualize the channels possibly involving intracellular superoxide, rats were injected with DCFH-DA, an intracellular reactive oxygen species (ROSs) indicator at the tail vein. As a result, their fascial lines on the inner side of the frontal abdominal wall including the linea alba emitted intense fluorescent light, forming a pattern which could be superimposed on the classic human meridians chart, indicating that ROSs are transported along a connective tissue of fascia.
The ROSs was confirmed to be superoxide in a controlled clinical trial, in which substituting acupuncture with topical application of TAT-SOD cream achieved a comparable effect on weight loss.
The biological function of the superoxide channel was illustrated by the investigation of the effect of severing the linea alba of a rat on its hepatic metabolic function. Rats with the linea alba severed awoke from choral hydrate anaesthesia in 3 hours in comparison with 20 minutes for the control group, due to a decreased choral hydrate metabolism caused by the failure of diffusing the hepatic superoxide through the linea alba. The reconnection of the two ends of the severed linea alba with a wire shortened the awaking time to 23 minutes, indicating the electronic nature of the transportation along the linea alba. It was further demonstrated that the passage of the hepatic superoxide to the linea alba was carried out by the thin film between the hepatic falciform ligament and the linea alba. The film emitted the green fluorescent light when the rat was injected with DCFH-DA, and the disruption of the film changed the electric current pattern along the linea alba.
Furthermore, the hepatic superoxide was found to be conducted through the bile duct wall to the intestine wall through DCFH-DA intracellular superoxide visualization of living rats, which suggests that the connective tissue is not the only channel for superoxide transportation and the intestine may possibly be a site for superoxide treatment. Those results indicate the existence of a superoxide disposal system implicating connective tissues such as fascia, falciform ligament and bile duct as transportation channels, and reveal its vital physiological role of electrically diffusing superoxide anions as a prerequisite of the normal function of the visceral organs.
To understand the whole picture of this hidden system, a formidable task lies ahead to elucidate how intracellular or mitochondrial superoxide is conducted from tissue cells to the fascia, and what cells inside fascia and in the bile duct and intestine wall are transporting superoxide, and where and how superoxide is stored and what the eventual fate of the diffused superoxide is.
About Pingfan Rao
Pingfan Rao, Ph.D., received BEng in food technology from Fuzhou University of China in 1982, Msc in food science from Hiroshima University in 1986, and phD in biochemistry from Osaka University of Japan in 1989. He is currently Professor and founding Director of CAS.SIBS-Zhejiang Gongshang University Joint Center for Food and Nutrition Research, and a Professor of Fuzhou University of China.
He is President (2012-14) of the International Union of Food Science and Technology, a fellow of International Academy of Food Science and Technology, Vice President of the Chinese Institute of Food Science and Technology. His research focuses primarily on identifying and characterizing bioactive proteins and expression and scale production of recombinant enzymes, protein derivatives as the active ingredients of tradition Chinese medicine and food, new methodology for cell separation and superoxide channels.