Studies On Protective Effects Of Carboxymethyl-β-1,3-glucan On The Human B Lymphoblasts Injury Induced By X-rays And ¹²C⁶⁺ Beam Radiation

Objective: To evaluate cytotoxic effects of carboxymethyl-β-1,3-glucan on HMy cell. Survival curves of cells radiated by X-rays and 12C6+ beam were fitted by the model of multitarget single hitting, and then drug effects on biological parameters analyzed. After HMy cells treated by X-rays and 12C6+ beam, the effects of carboxymethyl-β-1,3-glucan on HMy cells were detected, including the change of cell apoptotic, reactive oxygen species(ROS), mitochondrial membrane potential, malondialdehyde(MDA), superoxide dismutase(SOD) activity, DNA damage, and DNA damage repair, thereby to assess the protective effects and possible mechanisms of carboxymethyl-β-1,3-glucan on X-rays and 12C6+ beam irradiation.Materials and Methods: The proliferation of HMy cells treated by carboxymethyl-β-1,3-glucan with different incubation time were tested by the method of CCK-8, and screened out optimal concentration and time to use in subsequent experiments. HMy cell viability of different doses of X-rays and 12C6+ beam irradiation were detected by soft agar colony formation, and survival curves fitted by the model of multi-target single hitting to analyses the changes of radiation biology parameters. In concrete terms, the levels of cell apoptosis, ROS and mitochondrial membrane potential were quantitative measured by flow cytometry; the generation amount of MDA and SOD coming from lipid oxidation were detected by assay kits; the changes of micronucleus rate were explored by micronucleus test; the degree of DNA damage and repair was determined by single-cell alkaline gel electrophoresis assay.Results: Carboxymethyl-β-1,3-glucan is not toxic for HMy cell, and possesses the function of promoting cell proliferation. It can enhance HMy cell radiation resistance, reduce radiosensitivity and promote cell repair by analysing the changes of radiation biology parameters after X-rays and 12C6+ beam irradiation. Meanwhile, it can also significantly remit the levels of radiation-induced apoptosis, ROS and mitochondrial membrane potential, recover the activity of SOD, and inhibit the increasing of intracellular MDA content. In addition to, it obviously reduce micronucleus rate and the extent of NDA damage(comet tail length and tail DNA content) caused by X-rays and 12C6+ beam irradiation.Conclusion:(1) Carboxymethyl-β-1,3-glucan that is a safe and low toxicity drug, possess significantly protective effects on X-rays(low-LET) and 12C6+ beam(high-LET) irradiation.(2) Radiation-induced apoptosis and oxidative stress of HMy cell can been remarkable inhibited by carboxymethyl-β-1,3-glucan.(3) Carboxymethyl-β-1,3-glucan can alleviate the genotoxicity caused by radiation, increases resistance to radiation damage, and promote the repair of DNA damage in HMy cells.