N-acetylcysteine (NAC) emerges as a crucial factor in mitigating oxidative stress and inhibiting vascular endothelial activation in diabetic patients, through its effect on VEGF expression as VEGF is involved in the development of diabetic microvascular complications through the promotion of retinal angiogenesis and increased vascular permeability.

It was reported in the literature that NAC administration was safe in several studies. It was shown that the dose of 1200 mg is safe and effective.

To the best of our knowledge, the present study is the first to be designed to evaluate the effect of N-acetyl cysteine on diabetic retinopathy in type 2 diabetic patients.

Eligible patients will be randomly assigned into one of two groups. In the first group : patients will receive N-acetyl cysteine 1200 mg once daily for three months.

In addition to the standard of care antidiabetic management. In the second group: patients will take matched placebo for three months. In addition to the standard of care antidiabetic management.

1. Demographic data collection and history taking:

   1. Age
   2. Gender
   3. BMI
   4. Smoking status
   5. Diabetes duration
   6. Family history
   7. Medical history: Hypertension, Dyslipidemia, etc.
   8. Medications history especially those related to the occurrence of retinopathy

2. Clinical assessment, scoring & investigations:

   1. Systolic and diastolic blood pressures.
   2. Stage of retinopathy
   3. Ophthalmologic examination:
   4. Clinical examination to assess:Visual acuity and Field of vision

3. Laboratory assessment:

   1. Blood glucose measurement
   2. HbA1c level (%)
   3. HDL cholesterol (mmol/L)
   4. Non-HDL cholesterol (mmol/L)
   5. LDL cholesterol (mmol/L)
   6. Triglyceride (mmol/L)
   7. Glutathione peroxidase
   8. VEGF All patients will be followed up regularly for 3 months during the study period. They will be followed up weekly through telephone calls and will return every 4 weeks for clinical evaluation as well as verification of adherence to the study regimen. Any addition or deletion of a medication used by the study patients will be reported and dealt with if necessary.

At the end of the study the same tests will be repeated to compare the patients before and after taking N-acetyl cysteine.

Inclusion Criteria:

• Patients with type 2 diabetes mellitus

  • Patients with mild to moderate degrees of diabetic retinopathy
  • Patients over the age of 18 and under the age of 70 years
  • Patients who voluntarily give their informed consent
  • HbA1C (glycosylated hemoglobin) less than 10%
  • FBG less than 240 mg/dl
  • Body mass index (BMI) less than 40 kg/m2

Exclusion Criteria:

• • Patients with any other ophthalmologic conditions than diabetic retinopathy

  • Patients with previous surgical or laser treatment
  • Pregnant or breastfeeding patients
  • Patients using antioxidants.
  • Systemic anti-VEGF or pro-VEGF treatment within 4 months before randomization
  • Patients who are currently participating in other clinical trials
  • Severe liver or renal disease, (AST or ALT >3 times ULN or Total bilirubin >3 times ULN), (CrCl< 60 ml/min)
  • Current history of drug or alcohol abuse Malignancies