Rodent ozone exposure method for occasionally simulating human body exposure environment

Abstract

The invention belongs to the technical field of environmental medicine, and particularly relates to a rodent ozone exposure method for accidentally simulating a human body exposure environment. The method specifically comprises the following steps: firstly, an accidental exposure mode is adopted, so that the change of the adaptability of lungs and the adaptability of anterior pituitary hormone after rodents are continuously exposed to ozone for more than or equal to 3 days can be effectively avoided; and secondly, two concentration gradients, namely 0.399 + / -0.001 ppm and 0.799 + / -0.001 ppm, are set on the exposure dose of the ozone concentration, so that the dose of the ozone concentration exposed to the human body can be accurately reflected to be between 0.08 ppm and 0.16 ppm. According to the accidental exposure method based on the accurate dosage, the ozone exposure mode for people with the actual ozone concentration in China can be more accurately simulated, the mechanisms such as the human health toxicity effect of ozone can be accurately discussed, and the method has very important significance.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental medicine, and particularly relates to a method for exposing rodents to ozone in an accidental simulated human exposure environment. Background Art

[0002] As a highly reactive and strongly oxidizing environmental pollutant, ozone (O3) has shown an increasing trend in recent years under the background of climate change and global warming, and has become one of the important global public health problems. High-quality domestic and foreign epidemiological evidence shows that long-term exposure to air ozone pollution can lead to human chronic obstructive pulmonary disease, cardiovascular disease, metabolic disease, neurodegenerative disease, and fertility problems, and it is an "invisible killer" of population health. The "State of Global Air 2019" report pointed out that long-term exposure to ozone alone led to 472,000 deaths from chronic obstructive pulmonary disease globally, among which China accounted for 38%, about 178,200 people. Moreover, the number of deaths caused by ozone exposure has been increasing in recent years. China's recent epidemiological evidence found that short-term exposure to ozone can lead to asthma exacerbation, bronchial small airway inflammation, and the incidence risk of cardiovascular disease. The disease burden caused by short-term ozone exposure in each province of China was studied, and it was estimated that a considerable health benefit would be brought by the decrease in ozone concentration. When the daily maximum 8-hour average ozone concentration drops to the WHO guideline value of 100 μg / m 3 3, the number of avoidable deaths is about 1.2 million; when the ozone concentration drops to 70 μg / m 3 3, the number of avoidable deaths is about 1.6 million. The human health hazards caused by ozone air pollution are quite severe. Although relevant national departments have introduced corresponding air pollution management measures in recent years to reduce the harm to the human body. However, in terms of ozone pollution, most cities in China have shown varying degrees of increased pollution, so ozone pollution has not only not been effectively controlled, but has instead increased significantly.

[0003] At present, it is urgent to deeply analyze the human health toxicity mechanism and molecular action targets of ozone exposure. Existing animal ozone exposure experiments have relatively large defects: on the one hand, there is a large difference between the ozone exposure dose in animal experiments and the ozone exposure dose of real-world humans, and the dose of human exposure cannot be accurately simulated. On the other hand, most existing animal experiments use rodents as experimental subjects, and the breathing mode of rodents inhaling ozone through the respiratory system is different from that of the human respiratory system. Therefore, there are also certain defects in the exposure mode of rodent experiments. Based on the existing problems of ozone exposure in animal experiments, in order to more accurately simulate the mode of human exposure to ozone and accurately explore the mechanisms such as the human health toxicity effect of ozone, it is urgent to develop a new method for exposing rodents to air ozone. Summary of the Invention

[0004] In view of this, in order to solve the existing problems of ozone exposure in animal experiments in the above-mentioned background technology, the present invention provides a rodent ozone exposure method that occasionally simulates the human body exposure environment.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] An occasional rodent ozone exposure method simulating a human exposure environment is provided, wherein the rodents are exposed to ozone using an occasional exposure method, as follows:

[0007] Ozone exposure cohort 1 and ozone exposure cohort 2 were used, where

[0008] Ozone exposure cohort 1: The entire ozone exposure duration spanned 2 weeks, and the ozone exposure process was as follows: first, continuous ozone exposure for 2 days, followed by 1 day of rest; then, ozone exposure for 1 day, followed by 4 days of rest; and finally, continuous ozone exposure for 2 days, followed by 4 days of rest;

[0009] Ozone exposure cohort 2: The entire ozone exposure duration spanned 2 days, and the ozone exposure process was: only the last 2 days were exposed to determine the potential impact of ozone exposure in the last 2 days of ozone exposure cohort 1.

[0010] Further, during ozone exposure, the dosage was set to 0.399±0.001 ppm and 0.799±0.001 ppm.

[0011] Furthermore, during the ozone exposure period, ozone exposure was performed for 4 hours per day.

[0012] Furthermore, the rodents are rats and mice.

[0013] Furthermore, during the ozone exposure, the temperature was controlled at 21-23° C. and the humidity was controlled at 41-43%.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention adopts an occasional exposure method to simulate the exposure pattern in real life, avoiding the adaptive changes in the lungs and anterior pituitary hormones that occur after rodents are exposed to ozone for ≥3 consecutive days. It can more accurately simulate the pattern of human ozone exposure, and then accurately explore the mechanism of ozone's toxic effects on human health, which is of great significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the ozone exposure device.

[0017] Figure 2 Schematic diagram of the exposure process of ozone exposure cohort 1. DETAILED DESCRIPTION

[0018] For the convenience of understanding the present invention, the present invention will be described more comprehensively below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0019] Embodiment

[0020] I. Materials and Apparatus

[0021] Applicable rodent types: A total of 48 rats and mice.

[0022] The ozone exposure device is as Figure 1 shown and includes: an exposure chamber 1, an ozone input end 2, an ozone generator 3, an ozone output end 4, and an exhaust gas processor 5, all provided by Guangzhou Chuanghuan. Among them, the top cover of the exposure chamber 1 is hingedly connected to the chamber body, and a press lock assembly is provided on the top cover and the chamber body for anchoring the top cover to the chamber body; sealing gaskets are provided on the inner walls around the chamber body, an observation window is provided on the top cover, and a partition board is hermetically provided. The partition board is made of a transparent material, and a handle is provided on the outer frame of the top cover to facilitate the experimenter to open or close the top cover from the chamber body; the ozone inlet interface is located below the exhaust gas discharge interface, and the two are vertically misaligned, thereby ensuring the filling of ozone gas flow in the closed exposure space. The ozone generated by the ozone generator 3 is introduced into the exposure chamber 1 through the ozone input end 2 and then output to the exhaust gas processor 5 through the ozone output end 4. The ozone concentration in the exposure chamber 1 is detected by an ozone detector (Beijing Kang'erxing).

[0023] This device can accurately control the concentration of gaseous exogenous gas entering the animal body by the way of animal inhalation. In previous research, the poisoning device directly placed the animals in the exposure box. During the poisoning process, it was rather cumbersome to change the feed for the animals, add water, and clean up the excrement. The animals' activities were also likely to bump into the detection equipment in the exposure box, causing damage to the detection equipment. This device uses the method of placing the rat breeding cage as a whole in a closed space for an exposure-type gas poisoning experiment. During the poisoning process, the rats can ensure reasonable activity and living space in the breeding cage. At the same time, an exhaust gas processor is added to harmlessly process and evacuate the ozone-containing exhaust gas generated during the poisoning process.

[0024] II. Methods

[0025] (1) A total of 48 experimental rats or mice were randomly divided into an air filtration group and an ozone exposure group (0.399 ± 0.001 ppm and 0.799 ± 0.001 ppm) according to body weight, with 24 animals in each group. The air filtration group and the ozone exposure group were further divided into 3 subgroups, with 8 animals in each subgroup. During the exposure period, the temperature and humidity were controlled and maintained between 21 - 23 °C and 41 - 43% respectively.

[0026] (2) An episodic exposure method was used to better simulate the exposure pattern in real life and avoid the adaptation that occurs in the lungs of rodents after continuous exposure to ozone for ≥ 3 days. The reasons are as follows: On the one hand, after rodents are exposed to ozone for 2 days every day, ozone-induced lung injury / inflammation and metabolic changes generally begin to occur, resulting in a certain degree of adaptation. On the other hand, after 4 consecutive days of ozone exposure, the changes in anterior pituitary hormones are also worthy of attention.

[0027] The specific process of the episodic exposure method is as follows:

[0028] Two ozone exposure cohorts were used:

[0029] Ozone exposure cohort 1: The entire ozone exposure duration spanned 2 weeks. The ozone exposure process was as follows: First, continuous ozone exposure for 2 days, followed by a 1-day rest; then ozone exposure for 1 day, followed by a 4-day rest; finally, continuous ozone exposure for 2 days, with a 4-day rest. The schematic diagram of the exposure process of ozone exposure cohort 1 is shown in Figure 2 .

[0030] Ozone exposure cohort 2: The entire ozone exposure duration spanned 2 days. The ozone exposure process was as follows: Only expose for the last 2 days to determine the potential impact of the ozone exposure in the last 2 days of ozone exposure cohort 1.

[0031] During the above ozone exposure process, from 7 am to 11 am every day, the rats were exposed in the ozone exposure device for 4 hours.

[0032] Dose setting during the above ozone exposure process: Ozone gas is generated by a silent arc discharge generator (OREC) and passed through a mass flow controller. Rats in the air filtration group were exposed to filtered air. In the ozone exposure group, the average ozone concentrations were 0.000 ± 0.000 ppm, 0.399 ± 0.001 ppm, and 0.799 ± 0.001 ppm, respectively. Due to the difference in vital capacity between rodents and humans, there is a difference in lung dose of 4 - 5 between rodents and people with intermittent exercise. Using the ozone exposure doses of 0.399 ± 0.001 ppm and 0.799 ± 0.001 ppm can more accurately reflect the estimated ozone concentration dose of human exposure between 0.08 and 0.16 ppm. According to the 8-hour average ozone concentration standard set in the "Atmospheric Environment Quality Bulletin" of the Ministry of Ecology and Environment of China from 2021 to 2024, it is 160 μg / m 3 , which is approximately 160 μg / m 3 / 2.14 mg / m 3 = 0.075 ppm. Therefore, according to the current ozone concentration pollution situation in China, and the exposure amount of the Chinese population breathing ozone in the real world is above this concentration limit. Therefore, the doses of rodent exposure designed in the present invention are two gradients: 0.399 ± 0.001 ppm and 0.799 ± 0.001 ppm, which are closer to the air ozone concentration of human exposure in the actual environment when reflected in the human exposure dose.

[0033] After the exposure ends, subsequent treatment experiments are carried out.

[0034] The above is only a better example to explain the present invention, and it is not a limitation thereof. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention shall fall within the scope covered by the present invention.

Claims

1. A method for exposing rodents to ozone in an occasional manner simulating a human exposure environment, characterized in that: Rodents were exposed to ozone using an episodic exposure method as follows: Ozone exposure cohort 1 and ozone exposure cohort 2 were used, where Ozone exposure cohort 1: The entire ozone exposure duration spanned 2 weeks, and the ozone exposure process was as follows: first, continuous ozone exposure for 2 days, followed by 1 day of rest; then, ozone exposure for 1 day, followed by 4 days of rest; and finally, continuous ozone exposure for 2 days, followed by 4 days of rest; Ozone exposure cohort 2: The entire ozone exposure duration spanned 2 days, and the ozone exposure process was: only the last 2 days were exposed to determine the potential impact of ozone exposure in the last 2 days of ozone exposure cohort 1.

2. The method for sporadically simulating human exposure to ozone in rodents according to claim 1, characterized in that: During ozone exposure, the doses were set at 0.399 ± 0.001 ppm and 0.799 ± 0.001 ppm.

3. The method for sporadically simulating human exposure to ozone in rodents according to claim 1, characterized in that: During the ozone exposure period, ozone exposure was performed for 4 hours per day.

4. The method for sporadically simulating human exposure to ozone in rodents according to claim 1, characterized in that: Rodents include rats and mice.

5. The method for sporadically simulating human exposure to ozone in rodents according to claim 1, characterized in that: During ozone exposure, the temperature was controlled at 21-23°C and the humidity was controlled at 41-43%.

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