## 3 Results  
### Effects of L. regularis on Retinal BDNF Levels  
The levels of BDNF in the retinal of _L. regularis_-treated and untreated control and diabetic rats were determined by the ELISA method. In diabetic retina, the BDNF level considerably decreased compared to in non-diabetic control rats (20.3 \(\pm\) 2.2 vs. 11.4 \(\pm\) 1.5 pg/mg protein; \(p\) < 0.01). Although, when diabetic rats were given a high dose (300 mg/kg/day) of _L. regularis_ extract, the amount of BDNF in their retinas significantly increased compared to non-treated diabetic rats (11.4 \(\pm\) 1.5 vs. 17.4 \(\pm\) 2.1 pg/mg protein; \(p\) < 0.05), (Figure 1).  
Effects of L. regularis on Protein Expression of BDNF, proBDNF, and NGF in the Retina of Diabetic Rat  
Immunoblotting techniques were used to evaluate the protein contents of BDNF, proBDNF, and NGF in the retinas of _L. regularis_-treated and untreated diabetic rats (Figure 2). Analyses of protein band using densitometry revealed a significant decrease in retinal BDNF expression level in diabetic conditions as opposed to controls (100 \(\pm\) 8.3 vs. 30.3 \(\pm\) 5.2%; \(p\) < 0.01) (Figure 2). Although, _L. regularis_ treatments resulted in a considerable rise in BDNF levels in the diabetic retina (30.3 \(\pm\) 5.2 vs. 60.4 \(\pm\) 7.4%; \(p\) < 0.05). Likewise, the amount of NGF in diabetic retinas was considerably lower than that of control retinas (100 \(\pm\) 7.0 vs. 55 \(\pm\) 5.3%; \(p\) < 0.01), while the _L. regularis_ administration enhanced the level of NGF in the diabetic retina (55 \(\pm\) 5.3% vs. 75 \(\pm\) 7.2%; \(p\) < 0.05). As compared to non-diabetic rats, proBDNF level was substantially higher in the diabetes retina (100 \(\pm\) 6.4 vs. 250 \(\pm\) 18.5%; \(p\) < 0.01) (Figure 2). Conversely, the amount of proBDNF was markedly reduced in the _L. regularis_-treated diabetic retinas than without treatments (250 \(\pm\) 18.5 vs. 200 \(\pm\) 15.2%; \(p\) < 0.05).  
Figure 1: BDNF levels in the retinas of \(L\). _regularis_-treated diabetic and control rats. Retinal BDNF levels were measured using an ELISA kit. BDNF levels in diabetic retinas were compared with \(L\). _regularis_-treated diabetic rats and control rats. The values are means \(\pm\) SEM (standard error of mean) (* \(p\)! 0.01 vs. control; # \(p\)! 0.05 vs. diabetes, N = 6). C (control), D (diabetic) D + LRL (low-dose \(L\). _regularis_-treated diabetic rats), and D + LRH (high-dose \(L\). _regularis_-treated diabetic rats. The experiment was repeated twice.  
Figure 2: Expression of BDNF, pro-BDNF, and NGF in the high-dose \(L\). _regularis_ (LRH)-treated diabetic rats’ retinas. Densitometry was used to measure the band intensities. Representative bands of the blots of BDNF, pro-BDNF, NGF, and \(\beta\)-actin are shown in Panel (**A**). Band intensity ratios of BDNF protein bands (Panel (**B**)), Pro-BDNF protein bands (Panel (**C**)), and NGF protein bands are displayed as a percentage of control (Panel (**D**)). The values are means \(\pm\) SEM for six determinations. * \(p\)! 0.01, suggests a significant difference from their controls; # \(p\)! 0.05 suggests a significant difference from diabetic retinas. Experiments with immunoblotting were conducted twice.