Journal of J Occup Health 2005; 47: 277–285 Occupational Health The Prophylactic and Therapeutic Effects of Cholinolytics on Perfluoroisobutylene Inhalation Induced Acute Lung Injury Tianhong ZHANG1, Xigang ZHANG2, Zhihua SHAO3, Rigao DING1, Shunjiang YANG3, Jinxiu RUAN1, Xiaohong SUN1, Jin XU3, Chunqian HUANG1, Zuliang HU3 and Xianchang ZHANG1 1Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, 2307 Hospital and 3Quhua Hospital, Quhua Group Corporation, P. R. China Abstract: The Prophylactic and Therapeutic Effects cholinolytics might have prophylactic and therapeutic of Cholinolytics on Perfluoroisobutylene Inhalation roles in PFIB inhalation induced ALI. Induced Acute Lung Injury: Tianhong ZHANG, et al. (J Occup Health 2005; 47: 277–285) Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, P. R. China— Key words: Perfluoroisobutylene (PFIB), Acute lung Perfluoroisobutylene (PFIB) is a kind of fluoro-olefin injury (ALI), Cholinolytics, 3-Quinuclidinyl Benzilate that is ten times more toxic than phosgene. The (QNB), Anisodamine mechanisms of the acute lung injury (ALI) induced by PFIB inhalation remain unclear. To find possible Perfluoroisobutylene (PFIB), a colorless gas at normal pharmacological interventions, mice and rats were temperature, is a kind of fluoro-olefin that is ten times exposed to PFIB, and the prophylactic or therapeutic more toxic than phosgene1). It is usually generated as a effects of 3-quinuclidinyl benzilate (QNB) and by-product during the manufacture or the pyrolysis of anisodamine were studied and confirmed. It was polytetrafluoroethylene (PTFE), which is widely known observed that the wet lung/body weight and the dry lung/body weight ratios at 24 h after PFIB exposure by its trade name Teflon. Accidental inhalation can cause (130 mg/m3 for 5 min) were significantly decreased severe pulmonary edema, and even death because of when a single dose of QNB (5 mg/kg) was administered pulmonary congestion. It is a notorious hazard to human intraperitoneally either 30 min before exposure or 10 h beings in chemical industry accidents, fires and other after exposure. Anisodamine was without any emergencies2). Although diverse mechanisms, such as prophylactic or therapeutic effects at single doses below hydrofluoric acid hypothesis3), nucleophilic reaction4) and 30 mg/kg. The effects of QNB against PFIB inhalation reactive intermediate species5) are supposed to be involved induced ALI were well evidenced by the significantly in PFIB inhalation induced acute lung injury (ALI), there decreased mice mortality at 72 h, the total protein is still a long way to go to fully clarify the underlying concentration in bronchoalveolar lavage fluid at 24 h toxic mechanisms of the ALI induced by PFIB inhalation. after the PFIB exposure, as well as the ultrastructural Furthermore, there is no recognized prophylactic observations. The analysis of the time courses of lung sulfhydryl concentration, myeloperoxidase (MPO) measures for human PFIB exposure although animal activity and hemorheology assay showed that the studies have indicated that increased pulmonary toxicity of PFIB may be due to consumption of lung concentrations of free radical scavengers containing thiol protein sulfhydryl, influx of polymorphonuclear groups may be of value and N-acetylcysteine has been leukocytes (PMNs) into the lung, and increased found to be effective6). Early administration of peripheral blood viscosity at a low shear rate, all of corticosteroids, as used for phosgene, seems to be the which were partially blocked by QNB intervention only clinical recommendation for pharmacological except for PMN influx. The results suggest that intervention even though proof of their beneficial effects is still lacking in general7). Received Dec 7, 2004; Accepted March 14, 2005 When comparisons are made concerning the molecular Correspondence to: R. Ding, Institute of Pharmacology and structure8, 9), the time course of ALI after the inhalation Toxicology, Academy of Military Medical Sciences, Beijing 100850, exposure10, 11) and many other toxicological P. R. China (e-mail: [email protected]) characteristics12–14) between PFIB and phosgene, it seems 278 J Occup Health, Vol. 47, 2005 exposure were studied. Materials and Methods 1. General 1.1. Animals Specific pathogen-free male Wistar rats (260–300 g b.w.) and specific pathogen-free male mice (18–22 g b.w.) were used in this study. All animals were obtained from the Center of Medical Experimental Animals, the Academy of Military Medical Sciences (Beijing, P. R. Fig. 1. Possible interaction between PFIB and protein. China). The animals were housed in quiet, humidified, clean rooms with a light-cycle of 12 h/12 h for 1 week before use. They were fed with laboratory pellet food clear to us that both primary (direct) injury by the and tap water ad libitum except when they were in the chemical itself and secondary (indirect) injury, possibly exposure chamber. All the animal experiments were mediated by a later signal cascade network, are the two performed in accordance with the Guidelines for Animal key aspects of PFIB inhalation induced ALI. This is Experiments at the Chinese Academy of Medical because (1) the halogen and p-π electron conjugation in Sciences, Beijing, P. R. China. the molecular structure of PFIB make it possess a much 1.2. Doses of PFIB for animal exposure stronger electrophilicity, allowing it to attack much more PFIB was obtained from the Shanghai Institute of easily the nucleophilic groups of thiol (-SH), amino (-NH2) Organic Fluorine Materials at a purity of 98%. A flow- and hydroxy (-OH), distributed widely in the alveolar past whole-body exposure apparatus was used to expose membrane (Fig. 1), which are crucial to the maintenance small animals to PFIB, as described in our earlier paper15). of the cellular structure and function; and (2) as direct injury Except for the mortality study, PFIB inhalation doses were develops, a highly complex network is initiated and 130 mg/m3 × 5 min and 140 mg/m3 × 8 min for mice and established, resulting in an overshoot in inflammation15) rats, respectively, and were chosen for the convenient followed by severe lung damage, fulminating pulmonary observation of the pathophysiological changes without edema and even death. Multiple mediators such as TNF- fatal consequences. α16), IL-1β17), IL-818), metabolites of arachidonic acid19), adhesion molecule20), reactive oxygen species21), matrix 2. Experimental Design metalloproteinases22), neutrophil elastase23) and many other Test animals were generally divided into four groups. factors24) are thought to be involved in the latter mechanism. In groups 1) normal/saline and 2) normal/test drug, animals Any medical or pharmacological measure that can experienced the same exposure procedure with only pure effectively counteract the above-mentioned factors, air circulated in the chamber, and were treated with either theoretically, would impede or reverse the toxicity due saline or the test drug. In groups 3) PFIB/saline and 4) to PFIB or phosgene exposure. In fact, the antibody of PFIB/test drug, animals were exposed to PFIB in the same 25) 26) TNF-α , the COX2 inhibitor ibuprofen , SOD induction chamber, and administered either saline or the test drug. into the lung27), and other pharmacological interventions28) In the first part of the present study, comparisons of have all shown some prophylactic or therapeutic effects the effects of anisodamine and QNB (i.p.) on pulmonary on ALI experimentally. edema induced by PFIB inhalation were made by the Anisodamine, a typical cholinolytic extract from a weighing method; that is, the wet lung/body weight and Chinese herb, has been reported to possess effects of the dry lung/body weight ratios were calculated. To obtain microcirculation improvement29), stabilization of consistent data, the effects were expressed as relative lysosomal membranes30) and inhibition of the metabolism values of both ratios, with the averages of PFIB/saline of arachidonic acid31) along with its classical anti- groups at the same exposure were regarded as 100%, i.e., cholinergic effects, and is widely used clinically in the (PFIB/test drug) /(PFIB/saline). The difference between treatment of many diseases including ALI32, 33). In an a prophylactic and a therapeutic effect rest with the endeavor to throw some light on the complex process of administration of the test drug 30 min before or 10 h ALI and seek solutions for successful medical or after the PFIB exposure. The reason for the selection of pharmacological intervention, we hypothesized, that the treatment time-point 10 h after PFIB exposure, was cholinolytics used properly might have some prophylactic in consideration of the results from the time-course studies and therapeutic value against PFIB inhalation induced on the edema development pattern in our earlier study15), ALI. Accordingly, the effects of 3-quinuclidinyl benzilate which showed edema occurs after a latent period (8–12 (QNB), the most potent cholinolytic available, and h), as well as the experience of medical doctors that most anisodamine administered both before and after PFIB PFIB intoxicated patients usually are unconcerned in the Tianhong ZHANG, et al.: Intervention of PFIB-Induced ALI by Cholinolytics 279 asymptomatic period, and only when obvious symptoms min. Myeloperoxidase activity per gram wet lung was occur, such as cough, asthma and suffocation, do they calculated as follows: MPO activity (u/g lung)= ∆A ×