## 3 Results
### Effect of TQ on Glucose-Related Parameters in STZ-Toxicated Diabetic Rats  
The blood glucose levels (fasting) in all the rats were examined weekly from week 0 to 8 during the experiment. The average fasting blood glucose in STZ-injected diabetic rats was significantly higher (225.5 \(\pm\) 7.50 mg/dL) than that in normal control rats (94 \(\pm\) 5.30 mg/dL) (\(p\) < 0.05) (Figure 2). After 8 weeks of continues treatment with the TQ, a decline in fasting blood glucose level in STZ-induced diabetic rats (STZ + TQ) was noticed to be (146 \(\pm\) 6.20) (# \(<\) 0.05) as compared to the DC group (Figure 2). These finding reveal that TQ plays a substantial role in the induction of hypoglycemic effects or recovered the hyperglycemic state near to normal in diabetic rats.  
The STZ-treated rats showed significant reduction in insulin level (0.23 ng/mL) (\(p\) < 0.05) as compared to normal control group rats (1.1 ng/mL). Moreover, the diabetic animals treated with TQ (STZ + TQ) showed increased serum insulin level (0.4 ng/mL) and the difference in insulin level in the STZ-treated group treated with thymoquinone was statically significant (# < 0.05). These results suggest that TQ administration ameliorates STZ-induced diabetes mellitus (Figure 2).  
The glycosylated hemoglobin (HbA1c) level of the rats was also measured. The results confirmed that HbA1c level (10.64 \(\pm\) 1.15%) of STZ-intoxicated diabetic rats was significantly (\(p\) < 0.05) increased in comparison to the normal control (5.89 \(\pm\) 0.5%). STZ-induced diabetic plus TQ-treated animals showed significantly decreased percentage of HbA1c level (7.5 \(\pm\) 0.32%) (\(p\) < 0.05) and these findings demonstrated that TQ plays a vital role in decreasing the hemoglobin glycosylation level (Figure 3).  
Effect of Thymoquinone on Lipid Profile and Liver Function Enzyme Markers in STZ-Intoxicated Diabetic Rats  
The lipid profile was measured in all experimental groups. The results indicated that serum total cholesterol (TC) (139.37 \(\pm\) 8.7 mg/dL), triglycerides (TG) (132.3 \(\pm\) 9.5 mg/dL), low-density lipoprotein (LDL)-cholesterol (102.23 \(\pm\) 8.7 mg/dL) levels were significantly increased and high-density lipoprotein (HDL)-cholesterol decreased (38.6 \(\pm\) 7.2 mg/dL) in STZ-injected diabetic rats. The TQ treatment caused a significant reduction of TC, TG, LDL-cholesterol levels as (117.23 \(\pm\) 4.7 mg/dL, 201.23 \(\pm\) 9.4 mg/dL, 132.3 \(\pm\) 8.7 mg/dL) respectively. Moreover, the decreased serum HDL-cholesterol in diabetic rats was also upturned (61.9 \(\pm\) 7.2 mg/dL) toward the normal level after the treatment with TQ (\(p\) < 0.05) (Figure 4).  
Figure 2: The level of blood glucose and insulin change in different groups of rats after 8 weeks of continues treatment. The experimental animals were evenly distributed into each group (\(n\) = 8 per group). Data are means \(\pm\) standard error of the mean (SEM). Groups: Normal control (NC); disease control (DC) i.e., STZ-treated group; positive control (PC) animal treated with STZ and Glibenclamide; diabetic rats treated with TQ (STZ + TQ). \({}^{*}\)\(p\) < 0.05 (significant different of average glucose and insulin level between DC vs. NC) \({}^{\#}\)\(p\) < 0.05 (significant difference of average glucose and insulin level between DC vs. STZ + TQ).  
(194.6 \(\pm\) 3) in comparison to the control group (_p_ < 0.05). In addition, the treatment of STZ-treated diabetic rats with TQ led to a significant reduction in levels of liver function enzymes (112.6 \(\pm\) 9 U/L, 120.5 \(\pm\) 8 U/L, 139.3 \(\pm\) 9 U/L) towards normal levels, which is evidence that TQ protects hepatocytes (Figure 5).