Methods: Thirty male albino Wistar rats were separated into three equal groups as healthy group, trauma group, and trauma+rutin group. After anesthesia provided by intraperitoneal administration of 60 mg/kg ketamine and xylazine by inhalation at appropriate intervals, 200 g weight was dropped from 1 m height to the anterior chest wall of the animals in the trauma group (n=10) and trauma+rutin group (n=10) and pulmonary contusion was created. Thirty min after the trauma, 50 mg/kg of rutin was administered into the stomach of trauma+rutin group animals orally with gavage. The rats received rutin once daily for two days and were sacrificed 48 h later. Their lung tissues were removed and examined biochemically and histopathologically.
Results: Nuclear factor-kappa B, cyclooxygenase-2, and malondialdehyde levels increased in the trauma group compared to the healthy group, and rutin administration prevented this increase. Total glutathione levels decreased in the trauma group, and rutin administration also prevented this decrease. The histopathological findings were compatible with the biochemical findings.
Conclusion: Our study results suggest that rutin has a protective effect on contused lung tissue in rats.
Pulmonary contusion progresses with an inflammatory response leading to interstitial edema and protein extravasation. This inflammatory response is due to the early induction of cytokine expression. Indeed, a study reported that alveolar cytokine levels increased rapidly in the early posttrauma period.[3] Nuclear factor-kappa B (NF-kB) is responsible for the transcription of genes encoding various proinflammatory cytokines. It is also known that NF-kB regulates inflammatory cytokine production, and the NF-kB signaling pathway is essential for acute lung injury (ALI).[4] Typically, the cyclooxygenase-2 (COX-2) isoenzyme is present at shallow levels in cells, and its production is increased through the NF-kB signaling pathway. Induced COX-2 is the key enzyme involved in prostaglandin (PG) production from arachidonic acid (AA). It is well known that PGs are also mediators responsible for vasodilation and edema. A study reported that PC developed after trauma and COX-2 increased in the bronchoalveolar fluid.[5]
Another mechanism responsible for tissue damage is oxidative stress. A review article reveals a relationship between inflammation and oxidative stress.[6] Oxidative stress is likely to increase inflammation. One of the most remarkable biological targets of oxidative stress is lipids. Peroxidation of lipids (LPO) disrupts the membrane integrity of cells. Malondialdehyde (MDA) is the final toxic product of LPO and is an essential indicator of oxidative stress.[7] However, various antioxidant mechanisms balance the effects of oxidants in living organisms. As one of these, endogenous glutathione (GSH) is abundant in all cells and is the major soluble antioxidant. Reduced GSH protects membrane lipids from oxidative damage.[8]
In previous studies, the histopathological findings of the response to traumatic lung injury are consistent with biochemical findings. To illustrate, in a PC model, an increased number of polymorphonuclear leukocytes (PNLs) and a significant degree of intraalveolar edema in alveolar spaces and interstitium have been reported 24 h after trauma.[5]
The rutin has biological properties such as antioxidant, anti-inflammatory, inhibition of cytokine expression, and inhibition of PNL infiltration. Regarding the anti-inflammatory effect of rutin, studies have shown that it inhibits the NF-kB signaling pathway,[4] inhibits COX-2 increase,[9] and reduces capillary permeability.[10] Its antioxidative effect has been reported to prevent increased MDA levels and decreased GSH levels.[11] Histopathologically, rutin prevents PNL infiltration in the alveoli.[10]
Although early treatment of progressive lung injury has proven to have a critical role in prognosis, there is no specific treatment for PC, yet. In the present study, we aimed to investigate whether rutin exerted a protective effect against possible lung inflammatory and oxidative damage induced by BCT in a rat model.
Chemical substances
In the experiment, rutin was supplied from Solgar®
(Solgar Leonia, NJ, USA), and ketamine was supplied
from Pfizer Ilaçlari Ltd. Sti. (Türkiye).
Experimental groups
We classified the animals into three equal groups
as healthy group (HG), trauma group (TG), and
trauma+rutin group (TRG).
Experiment procedure
In rats, the trauma procedure was performed
with anesthesia administering 60 mg/kg ketamine
intraperitoneally and xylazine by inhalation at
appropriate intervals. When the animals remained
stable supine, the period was considered the appropriate anesthesia period for administering trauma.[12] After
ketamine injection, the rats were kept waiting for
this favorable period to occur. During anesthesia, PC
was created by dropping 200 g weight on the anterior
chest wall of animals in TG (n=10) and TRG (n=10)
groups, and PC was created. The resulting energy
was calculated to be 1.96 Joules with the formula
of E=mgh (E: energy, m: reduced weight; 0.2 kg, g:
gravity; 9.8 m/s2, h: height; 100 cm). As a result, PC
was induced by administering 1.96 Joules of energy
to rats.[13] Thirty min after the contusion, 50 mg/kg
of rutin was administered into the stomach of TRG
group animals orally with gavage. The rutin was
used once a day for two days. The same volume of
0.9% sodium chloride (NaCl) was administered orally
to the HG (n=10) group. At the end of this period,
the animals were killed with high-dose ketamine
anesthesia, and their lung tissues were removed. The
removed lung tissues were examined biochemically
and histopathologically. The evaluation was made
comparing the results obtained from TG and HG
groups with the TRG group results.
Preparing the samples for biochemical analysis
At this stage of the study, 0.2 g from each removed
tissue was weighed. Tissues were homogenized in an
icy environment completing 1.15% potassium chloride
solution for MDA determination to 2 mL in phosphate
buffer pH=7.4 for total GSH (tGSH), COX, NF-kB,
and protein measurements. It was, then, centrifuged at
+4°C and 10,000 rpm for 15 min. The NF-kB, COX-2,
MDA, and tGSH levels in the supernatants obtained
from the prepared homogenates were determined using
appropriate methods as prescribed in the literature.
Protein measurement
Protein concentration measurement was done
according to the Bradford MM method.[14] The
principle of the measurement is based on measuring
the absorbance at 595 nm of the colored complex formed by the binding of the Coomassie Brilliant Blue
G-250 dye to proteins. All tissue analysis results were
standardized by dividing them into protein.
Nuclear factor-kappa B analysis
Tissue-homogenates NF-kB concentrations were
measured using rat-specific sandwich enzyme-linked
immunosorbent assay. Rat NF-kB ELISA immunoassay
kits (Cat. No:201-11-0288, Sun Red). Tissue NF-kB
concentration was calculated as ?g/g protein.
Measurement of cyclooxygenase activity
Cyclooxygenase activity in rat lung tissue was
measured using a COX activity assay kit (Cayman,
Ann Arbor, MI, USA). Tissue NF-kB concentration
was calculated pmoL/mg protein.
Malondialdehyde determination
The MDA levels were determined
spectrophotometrically at 532 nm according to the
method described by Ohkawa et al.[15] This m ethod
is based on spectrophotometric measurement of
absorbance of colored complex, which is formed by
thiobarbituric acid and MDA at a high temperature
(95°C). Tissue MDA concentration unit was given as
µmoL/g protein.
Total glutathione determination
5,5'-Dithio-bis (2-nitrobenzoic acid) (DTNB)
in the measurement environment was a disulfide
chromogen and was easily reduced by sulfhydrylgroup
compounds. The resulting yellow color was
measured spectrophotometrically at 412 nm.[16] Tissue
tGSH concentration unit was given as nmoL/g protein.
Histopathological examination
All tissue samples were first identified in a 10%
formaldehyde solution for light microscope assessment.
Following the identification process, tissue samples
were washed under tap water in cassettes for 24 h. To remove the water within tissues, samples were treated
with a conventional alcohol grade (70%, 80%, 90%,
and 100%). Tissues were, then, passed through xylol
and embedded in paraffin. Four to five-micron sections
were cut from the paraffin blocks, and hematoxylineosin
staining was administered. Their photos were
taken following the Olympus DP2-SAL firmware
program (Olympus® Inc., Tokyo, Japan) assessment.
The pathologist blind carried out a histopathological
assessment for the study groups. The histopathological
damage severity in each lung tissue section was
scored between 0 and 3 degrees (0-normal, 1-mild
damage, 2-moderate damage, and 3-severe damage)
and displayed as a table.
Statistical analysis
Statistical analysis was performed using the IBM
SPSS for Windows version 19.0 (IBM Corp., Armonk,
NY, USA). Descriptive data were expressed in mean
± standard deviation (SD) for continuous variables.
The significance of the variations among the groups
was determined using one-way analysis of variance
(ANOVA), followed by the Tukey test analysis. The
histopathological examination revealed the group
differences by the Kruskal-Wallis test, and the Dunn
test was used to identify which groups were different.
A p value of <0.05 was considered statistically
significant.
Table 1. Biochemical results of the study groups
Cyclooxygenase-2 analysis results
As shown in Figure 1, COX-2 enzyme activity
in the lung tissues increased in the TG compared
to the HG. A statistically significant difference was
found between these two groups (p<0.001). This
increase was prevented by administering rutin, and a
statistically significant difference was found between
the TG and the TRG (p<0.001). The differences in
mean levels of COX-2 among the groups are shown
in Table 1.
Malondialdehyde analysis results
When the HG and TG were compared in terms
of MDA values, there was an increase in the TG
compared to the HG, and the difference between these
two groups was statistically significant (p<0.001). This
oxidant increase was prevented administering rutin,
and a significant difference was found between the TG
and TRG (p<0.001). When the TRG and the HG were
compared, no statistically significant difference was
observed between the two groups (p=0.415) (Figure 2).
The differences in mean levels of MDA among the
groups are shown in Table 1.
Total glutathione analysis results
As shown in Figure 2, a decrease in tGSH level
was observed in the TG compared to the HG, and a
significant difference was found between these two
groups (p<0.001). In the TRG, the decrease in tGSH
level was prevented, and a significant difference was
observed between the TG and TRG (p<0.001). There
was no statistically significant difference between the
TRG and the HG (p=0.08). The differences in mean
levels of tGSH among the groups are shown in Table 1.
Histopathological evaluation
When the lung tissue sections of the HG were
analyzed, the bronchiole structures, alveoli, and
vascular structures had typical histological lung
tissue images (Figure 3a). When the TG in which
PC was induced by blunt trauma was analyzed, the length of the bronchiolar epithelium was shortened
and flattened. Bronchial-associated lymphoid
tissue increased due to intense inflammatory cell
infiltration in the peribronchial area. Furthermore,
the presence of intensive intra-alveolar edema
and dense hemorrhage in the interalveolar area
were observed. Congestion in the blood vessels
and increased connective tissue in the perivascular
areas were determined (Figure 3b). The bronchiole
epithelium was normal, and the inflammatory cell
infiltration in the peribronchial area decreased
considerably in the treatment group. There was
slight edema in the intra-alveolar area, and the
interalveolar regions had a normal appearance. The
congestion in the blood vessels almost disappeared,
and perivascular connective tissue regained its normal
appearance (Figure 3c). The severity evaluation of the
histopathological findings of the groups is shown in
Table 2.
In the present study, a significant increase in COX-2 activity was observed in damaged lung tissue induced by BCT. One of the primary mechanisms playing a role in inflammatory damage is the COX-2 enzyme accompanied by the AA metabolism. The COX-2 isoenzyme, which is rapidly induced in damaged tissues, plays a key role in shaping inflammation and producing PG from AA. Moreover, it was stated that the induction of COX-2 in damaged tissue causes an increase in the production of reactive oxygen species (ROS).[21]
As known, changing the oxidant/antioxidant balance in tissues in favor of oxidants causes tissue damage, and this is known as oxidative stress. Excessive ROS in damaged tissue accelerates LPO reaction.[22] The MDA, the final product of LPO, causes cell death by damaging the cell membrane, impairing ion permeability, and inactivating enzyme activity. It has been known for a long time that high MDA levels are a good indicator of ROS formation.[15] There are several studies in the literature indicating the increase of MDA levels in damaged tissue. A study on PC induced by BCT revealed an MDA increase in the lung tissues of the rats.[23]
The ROS is produced in living tissues in a continuous and controlled way. For maintaining tissue integrity and functions at normal levels, overproduced ROS are neutralized in a controlled manner by endogenous GSH and other antioxidants. It has been shown that endogenous GSH protects the sulfhydryl structures of proteins and plays a role in protecting cells against cytotoxic substances.[24] Dogan et al.[25] proved that GSH levels decreased in lung tissue after BCT-induced PC. Our experimental results suggested that the post- PC oxidant/antioxidant balance in the lung tissue changed in favor of oxidants, supporting the beginning of oxidative damage in the lung.
It has been histopathologically indicated in almost all studies carried out on PC induced by blunt trauma that inflammation causes an increase in alveolocapillary membrane permeability and alveolar edema. In most of these studies, histopathological density of PNL in the lung tissue was statistically significant compared to the healthy group.[26] In experimental models, alveolar integrity deterioration, intra-alveolar hemorrhage, interstitial edema, interalveolar and intra-alveolar PNL deposition have been reported in tissues with PC.[27] In our study, the histopathological results are similar to previous studies in terms of the findings related to intense hemorrhage, inflammatory cell accumulation, edema, and vascular congestion in the TG.
It is obvious that physicians need to control the secondary damage mechanism in lung contusion as early as possible. For this purpose, there are experimental studies using sildenafil and hyperbaric oxygen in the literature.[28,29] There are more experimental studies to observe the antioxidant and anti-inflammatory effects of vitamins. According to Sirmali et al.,[30] vitamin C had a remarkable antioxidative effect on PC. Satria and Umar[31] also showed that the combination of vitamins C and E reduced cell death in rats with PC. Gökçe et al.[32] divided the animals with PC into groups and administered coenzyme Q, vitamin C, vitamin E, and dexamethasone to each animal group separately. They obtained the most significant anti-inflammatory response with the coenzyme Q group and the most significant antioxidative result with the vitamin C group. Taken together, these findings suggest that using vitamin derivatives in the early stages of PC is beneficial.
In the literature, there is no study investigating the effect of rutin against PC-associated inflammation. However, in studies in which lipopolysaccharide induces lung damage, it has been shown that rutin exerts its anti-inflammatory effects by inhibiting the NF-kB signaling pathway.[4] In a cell culture study, rutin inhibited the inflammatory responses of macrophages by blocking the NF-kB signaling pathway.[33] The production of mediators that caused increased capillary permeability occurred through the COX pathway, and this pathway was inhibited by various anti-inflammatory drugs.[21] A study showed that rutin significantly reduced COX-2 expression depending on the dose.[34] In our study, the low levels of NF-kB and COX-2 in the group administered with rutin after trauma supported the finding that rutin inhibited the COX pathway through NF-kB inhibition.
Previous in vitro and in vivo studies have shown that rutin can reduce oxidative stress. In the literature, rutin has been suggested to be a powerful antioxidant agent.[35] It prevents increased oxidants such as MDA and the decrease of antioxidants such as GSH in both ischemia-reperfusion injuries[36] and lung injury.[4] In a study in which oxidative stress was created with pulmonary edema, low MDA and high GSH levels were obtained by rutin administration.[11] In our study, low MDA and high tGSH levels obtained by administering rutin can be interpreted as rutin to have an antioxidative effect on PC.
In a study in which lung damage was induced, histopathological results indicated that the findings such as bleeding, interstitial edema, thickening of the alveolar wall, and PNL infiltration decreased with rutin administration.[4] In parallel with this study, several studies reported that rutin decreased protein concentration and inflammatory cell infiltration in bronchoalveolar lavage fluid.[10,34] Considering our treatment group, rutin reduced inflammation that developed after traumatic lung injury. There were no significant histopathological findings, except for mild inflammatory infiltration and mild alveolar edema.
Nonetheless, there are some limitations to this study. The effect of rutin on lung tissue in pulmonary contusion accompanying multiple organ injuries is unknown. It is also unclear whether the curative effect of rutin is dose-dependent. In our study, we were unable to compare the effect of rutin and other vitamins on PC and superiority of one to another.
In conclusion, our study results showed that the increase in NF-kB, COX-2, and MDA levels and the decrease in tGSH levels caused inflammation and oxidative stress in PC induced by BCT in rats. Furthermore, lung injury induced by BCT was indicated histopathologically. Biochemical and histopathological findings caused by trauma were found to be improved with rutin administration. These results suggest that rutin seems to be helpful in the treatment of PC complications. However, further clinical studies are needed to confirm these findings,
Ethics Committee Approval: The study protocol was approved by the Atatürk University Animal Experimentation Ethics Committee (No: 75296309-050.01.04-E.2000272506, Date: 02.11.2020).
Data Sharing Statement: The data that support the findings of this study are available from the corresponding author upon reasonable request.
Author Contributions: Idea/concept: B.E., H.S.; Design: B.E., R.M., Y.B., H.S.; Control/supervision: H.S., T.A.Ç.; Data collection and/or processing, analysis and/or interpretation: B.E., R.M., G.N.Y., T.A.Ç.; Literature review: B.E., R.M., Y.B.; Writing the article: B.E., Y.B.; Critical review: H.S., G.N.Y., T.A.Ç.; References and fundings: B.E., R.M., Y.B.; Materials: R.M., G.N.Y., H.S., T.A.Ç.
Conflict of Interest: The authors declared no conflicts of interest with respect to the authorship and/or publication of this article.
Funding: The authors received no financial support for the research and/or authorship of this article.
1) Rendeki S, Molnár TF. Pulmonary contusion. J Thorac Dis
2019;11(Suppl 2):S141-S151.
2) Zhou D, Qiu J, Liang Y, Dai W, Yuan D, Zhou J.
Epidemiological analysis of 9,596 patients with acute
lung injury at Chinese Military Hospitals. Exp Ther Med
2017;13:983-8.
3) Maxwell RA, Gibson JB, Fabian TC, Proctor KG. Effects of a
novel antioxidant during resuscitation from severe blunt chest
trauma. Shock 2000;14:646-51.
4) Yeh CH, Yang JJ, Yang ML, Li YC, Kuan YH. Rutin
decreases lipopolysaccharide-induced acute lung injury via
inhibition of oxidative stress and the MAPK-NF-kB pathway.
Free Radic Biol Med 2014;69:249-57.
5) Dolkart O, Amar E, Shapira S, Marmor S, Steinberg EL,
Weinbroum AA. Protective effects of rosuvastatin in a rat
model of lung contusion: Stimulation of the cyclooxygenase
2-prostaglandin E-2 pathway. Surgery 2015;157:944-53.
6) Mittal M, Siddiqui MR, Tran K, Reddy SP, Malik AB.
Reactive oxygen species in inflammation and tissue injury.
Antioxid Redox Signal 2014;20:1126-67.
7) Del Rio D, Stewart AJ, Pellegrini N. A review of recent
studies on malondialdehyde as toxic molecule and biological
marker of oxidative stress. Nutr Metab Cardiovasc Dis
2005;15:316-28.
8) Curello S, Ceconi C, Bigoli C, Ferrari R, Albertini A,
Guarnieri C. Changes in the cardiac glutathione status after
ischemia and reperfusion. Experientia 1985;41:42-3.
9) Lee S-J, Lee SY, Ha HJ, Cha SH, Lee SK, Hur SJ. Rutin
attenuates lipopolysaccharide-induced nitric oxide production
in macrophage cells. Journal of Food and Nutrition Research
2015;3:202-5.
10) Chen WY, Huang YC, Yang ML, Lee CY, Chen CJ, Yeh CH,
et al. Protective effect of rutin on LPS-induced acute lung
injury via down-regulation of MIP-2 expression and MMP-9
activation through inhibition of Akt phosphorylation. Int
Immunopharmacol 2014;22:409-13.
11) Bilgin AO, Mammadov R, Suleyman B, Unver E, Ozcicek
F, Soyturk M, et al. Effect of rutin on cytarabine-associated
pulmonary oedema and oxidative stress in rats. An Acad
Bras Cienc 2020;92:e20190261.
12) Demiryilmaz I, Turan MI, Kisaoglu A, Gulapoglu M,
Yilmaz I, Suleyman H. Protective effect of nimesulide
against hepatic ischemia/reperfusion injury in rats: Effects
on oxidant/antioxidants, DNA mutation and COX-1/COX-2
levels. Pharmacol Rep 2014;66:647-52.
13) Weber B, Lackner I, Haffner-Luntzer M, Palmer A, Pressmar
J, Scharffetter-Kochanek K, et al. Modeling trauma in rats: Similarities to humans and potential pitfalls to consider. J
Transl Med 2019;17:305.
14) Bradford MM. A rapid and sensitive method for the
quantitation of microgram quantities of protein utilizing
the principle of protein-dye binding. Anal Biochem
1976;72:248-54.
15) Ohkawa H, Ohishi N, Yagi K. Assay for lipid peroxides in
animal tissues by thiobarbituric acid reaction. Anal Biochem
1979;95:351-8.
16) Sedlak J, Lindsay RH. Estimation of total, protein-bound,
and nonprotein sulfhydryl groups in tissue with Ellman's
reagent. Anal Biochem 1968;25:192-205.
17) Bakowitz M, Bruns B, McCunn M. Acute lung injury and
the acute respiratory distress syndrome in the injured patient.
Scand J Trauma Resusc Emerg Med 2012;20:54.
18) Hoth JJ, Stitzel JD, Gayzik FS, Brownlee NA, Miller PR,
Yoza BK, et al. The pathogenesis of pulmonary contusion:
An open chest model in the rat. J Trauma 2006;61:32-44.
19) Zhang B, Wang B, Cao S, Wang Y, Wu D. Silybin attenuates
LPS-induced lung injury in mice by inhibiting NF-kB signaling
and NLRP3 activation. Int J Mol Med 2017;39:1111-8.
20) Wang Y, Zhang J, Gao X, Li Q, Sun D. In vitro and in vivo
anti-inflammatory effect of Zaluzanin D isolated from
Achillea acuminate. Int Immunopharmacol 2021;90:107130.
21) Suleyman H, Cadirci E, Albayrak A, Halici Z. Nimesulide
is a selective COX-2 inhibitory, atypical non-steroidal antiinflammatory
drug. Curr Med Chem 2008;15:278-83.
22) Kisaoglu A, Borekci B, Yapca OE, Bilen H, Suleyman H.
Tissue damage and oxidant/antioxidant balance. Eurasian J
Med 2013;45:47-9.
23) Sırmalı M, Solak O, Tezel C, Sırmalı R, Ginis Z, Atik
D, et al. Comparative analysis of the protective effects
of caffeic acid phenethyl ester (CAPE) on pulmonary
contusion lung oxidative stress and serum copper and zinc
levels in experimental rat model. Biol Trace Elem Res
2013;151:50-8.
24) Knapen MF, Zusterzeel PL, Peters WH, Steegers EA.
Glutathione and glutathione-related enzymes in
reproduction. A review. Eur J Obstet Gynecol Reprod Biol
1999;82:171-84.
25) Dogan G, Dogan G, Karaca O, Ayaz E. Effects of Pelargonium
sidoides (UMCA ®) on pulmonary contusion from blunt
thoracic trauma in rats. Ann Med Res 2020;27:2319-25.
26) Keskin Y, Bedel C, Gökben Beceren N. Investigation of
histopathological and radiological effects of surfactant
treatment in an experimental female rat model of lung
contusion. Iran J Basic Med Sci 2019;22:1153-7.
27) Kao RL, Huang W, Martin CM, Rui T. The effect of
aerosolized indomethacin on lung inflammation and
injury in a rat model of blunt chest trauma. Can J Surg
2018;61:S208-S218.
28) Yeginsu A, Ergin M, Gurlek K, Saylan O. The effects
of sildenafil on lung contusion. Turk Gogus Kalp Dama
2011;19:613-7.
29) Yiyit N, Türüt H, Işıtmangil T, İpçioğlu OM, Uzun G, Berber
U, et al. Pulmoner kontüzyon tedavisinde yeni bir yöntem:
Hiperbarik oksijen, bir deneysel çalışma. Turk Gogus Kalp
Dama 2012;20:875-82.
30) Sirmali R, Giniş Z, Sirmali M, Solak O, Şeliman B,
Ağaçkiran Y, et al. Vitamin C as an antioxidant: Evaluation
of its role on pulmonary contusion experimental model. Turk
J Med Sci 2014;44:905-13.
31) Bermansyah, Satria G, Umar A. Effectiveness of vitamin
C and vitamin E antioxidant combination on caspase-3
expression in Wistar white rat pulmonum contusion. Sriwijaya
Journal of Surgery 2020;3:31-44.
32) Gokce M, Saydam O, Hanci V, Can M, Bahadir B. Antioxidant
vitamins C, E and coenzyme Q10 vs dexamethasone:
Comparisons of their effects in pulmonary contusion model.
J Cardiothorac Surg 2012;7:92.
33) Su KY, Yu CY, Chen YP, Hua KF, Chen YL.
3,4-Dihydroxytoluene, a metabolite of rutin, inhibits
inflammatory responses in lipopolysaccharide-activated macrophages by reducing the activation of NF-kB signaling.
BMC Complement Altern Med 2014;14:21.
34) Huang YC, Horng CT, Chen ST, Lee SS, Yang ML, Lee CY,
et al. Rutin improves endotoxin-induced acute lung injury via
inhibition of iNOS and VCAM-1 expression. Environ Toxicol
2016;31:185-91.