Preparation of ANDRO-NS
The particle size distribution of the nanoparticles indicated that the preparation was uniform and a single peak was detected using laser light scattering. The average particle size was 568.51±13.74 nm (Fig 1). The nanoparticles appeared round or oval and uniform in shape under TEM (Fig 2). These results indicated that the prepared nanoparticles have a small and stable grain size. The concentration and type of stabilizer have an important impact on the particle size of the suspension. (
Bhavna and Ali, 2014;
Fujimura et al., 2016). In order to ensure the stability of the suspension, compound stabilizers are often used in production. When Poloxamer 188 or Tween-80 were used alone, the andrographolide nanosuspensions produced were unstable and the crystals began to aggregate and became larger when left for 24 hours. Therefore, in this experiment, Poloxamer 188 and Tween 80 were used as surfactants, which may be because both are non-ionic surfactants that maintain the stability of the suspension by creating steric hindrance.
In vitro release test results of ANDRO-NS
Conversion of the andrographolide to ANDRO-NS significantly improved its solubility and at a dissolution time of 180 min, the level of ANDRO-NS was 2.43 times that of andrographolide (Fig 3). This indicated that our preparation method effectively increased the specific surface area of andrographolide. The release curves for andrographolide and ANDRO-NS were fitted with the Weibull model
in vitro release and the equations was y = 0.010 x + 0.145 (r=0.900) and y=0.027 x + 0.310 (r=0.922).
Acute toxicology test results
The initial
in vivo experiments were meant to assess whether mice could tolerate extreme doses of ANDRO-NS. Mice in the high-dose group (1200 mg/kg) showed mental excitement after being administered by gavage for 1-2 minutes, then they wandered, ran, jumpedÿand eventually fell to the ground in full-body convulsions. The mice began to die after about 5 minutes. Mice in the 251.65 mg/kg dose group developed mild neurological symptoms with slight muscle twitches and gathered themselves into a pile. After about 2 hours, they returned to normal state without death. They appeared completely normal after one day. These observations indicated that the median lethal dose (LD
50) was 548.91 mg/kg with a 95% CI of 468.19-645.03 mg/kg (Table 1). Researchers have found through literature studies that LD
50 of andrographolide has a wide dynamic range from 500 to 2000 mg/kg
(Chen et al., 2005). They also observed that andrographolide had no obvious effect on toxicity by nanosuspension.
Subacute toxicity test results
This study modified the dosages based on the acute toxicity test results and administered ANDRO-NS at 50, 25 and 5 mg/kg for seven days. In all test groups, white blood cells (WBC) and hemoglobin (HGB) were significantly lower thanthose in the control group (P<0.05). The red blood cells (RBC) in the high-dose group decreased by 26.40%, reaching the level of statistical significance (P<0.05). Interestingly, the platelet (PLT) count in the high- and medium-dose groups was significantly higher than in the control group (11.42% and 9.80%, respectively). In comparison between the test groups, the levels of RBC and HGB in the high-dose group were notably lower than those in the medium- and low-dose groups (P<0.05). In addition, PLT counts for the high- and medium-dose groups were remarkably higher than those in the low-dose group (P<0.05).
After fourteen days of ANDRO-NS administration, the WBC counts in each test group became less than the control group (P<0.05), while the numbers for RBC, HGB and PLT in the high- and medium-dose groups increased comparing to the control group (P<0.05). Set test groups side by side, the rate of RBC, HGB and PLT s in each group were significantly higher than those in the low-dose group (P<0.05). Overall, WBC, RBC, PLT and HGB levels for each test group increased after fourteen days (P<0.05) (Table 2).
The serum biochemical blood test of mice in the high dosage group showed that after seven days of ANDRO-NS administration, aspartate aminotransferase (AST), creatinine (CRE) and blood urea nitrogen (BUN) grew by 43.68%, 25.47% and 54.61% compared to the control group while reaching the statistical significance (P<0.05). AST, CRE and BUN for the low-dose group were also higher than those of the control group, but the differences were not significant (P>0.05). AST, ALT, CRE and BUN levels in the high-dose group were greater than middle- and low-dose groups. In contrast, AST and BUN for the high-dose group were 41.17% and 31.31% than low-dose groups, respectively and significant (P<0.05). After fourteen days of ANDRO-NS administration, the numbers of AST, ALT, CRE and BUN for each test group were significantly higher than the control groups (P<0.05). The CRE level in the high-dose group was 2.23 times higher than that of the control group, while the BUN level was 3.33 timer higher. The comparison between test groups indicated that AST, ALT, CRE and BUN in the high-dose group were much higher than those in the medium- and low-dose groups (P<0.05). AST, ALT, CRE and BUN in the blood of the high-dose group and the medium-dose group increased significantly after 14 days of administration compared with the 7-day levels (Table 3). Blood physiological and biochemical indicators are important to evaluate the pathology of the body, tissues and organs
(Wlaź et al., 2015). Alanine transferase (ALT) and alkaline phosphatase (ALKP) are used to determine whether the liver is damaged, while CRE and BUN can indicate whether the kidney is damaged (
Al- Batran et al., 2013).
Hu et al., (2010) revealed that the levels of ketamine (KET), erythrocytes (ERY), BUN, CRE, ALP, lactate dehydrogenase (LDH) and N-acetyl-glucoseaminidase (NAG) in the urine were increased in the high-dose Lianbizhi (andrographolide) Injections treated rats, we observed that the RBC, HGB, PLT, AST, ALT, CREA and BUN levels of high-dose and medium-dose groups were higher than that of the control group after 14 days of administration.
We also examined the histology of the kidneys and livers of the mice in the three test groups compared with the control group seven days and fourteen days after the ANDRO-NS administration. The renal interstitium for the high-dose group showed signs of hemorrhage. Compared with the control group, the renal interstitium of the mice in the high-dose and medium-dose groups was wide (Fig 4C and D). There was also sporadic hemorrhaging in the renal interstitium of the low-dose group (Fig 4B). Fourteen days after the ANDRO-NS administration, compared with the control group (Fig 5A), the high-dose group exhibited renal glomerulus atrophy, vacuolar degeneration of renal tubular epithelial cells, sporadic bleeding and inflammatory cell infiltration (Fig 5D). The renal tubules in the low-dose group were also dilated (Fig 5B).
After seven days of the experiment, the liver examination showed that the central hepatic veins of the high-dose group were dilated and the hepatocyte cords were disconnected (Fig 6D). Hepatocytes of the medium-dose group were loosened (Fig 6C). These changes were not seen in the low-dose group and the hepatocyte cords remained intact. The sinusoidal bleeding, necrosis and other phenomena were absent compared to controls (Fig 6A and B). After fourteen days of the administration, compared with the control group (Fig 7A), the hepatocellular edema and hepatic necrosis occurred in the high-dose group (Fig 7D). There were signs of hepatocyte edema and hepatic sinusoidal degeneration in the medium-dose group (Fig 7C). In the low-dose group, hepatocytes were arranged irregularly, hepatic sinusoids were irregular and some bleedingsymptoms were observed (Fig 7B). Although, it is generally known that andrographolide can cause nephrotoxicity
(Lu et al., 2010; Lu et al., 2011). However, these types of livers damage were more serious than reported in the literature
(Fang et al., 2007). This phenomenon indicates that the andrographolide prepared by the study, caused an inflammatory reaction and fourteen days of high-dose administration resulted in hepatocyte edema and liver cell necrosis. The toxicity mechanism for ANDRO-NS needs further study.